!2983 Dataset Tensor class cleanup

Merge pull request !2983 from h.farahat/tensor_class

mindspore/ccsrc/minddata/dataset/api/de_pipeline.cc

@@ -511,8 +511,9 @@ Status DEPipeline::FetchDataFromTensorRow(const TensorRow &row,
       RETURN_IF_NOT_OK(s);
       if (data != nullptr) (*row_raw_data)[column_name] = std::move(*data);
     } else if (column_type == DataType::DE_STRING) {
-      auto buffer = tensor->GetStringsBuffer();
+      std::string_view sv;
-      std::string ss(reinterpret_cast<const char *>(buffer));  // assume scalar string tensor
+      RETURN_IF_NOT_OK(tensor->GetItemAt(&sv, {0}));  // assume scalar string tensor
+      std::string ss(sv);
       (*row_raw_data)[column_name] = std::move(ss);
       continue;
     } else {
@@ -1678,13 +1679,13 @@ Status DEPipeline::ParsePadInfo(py::handle value, PadInfo *pad_info) {
       if (py::isinstance<py::str>(tp[1])) {
         std::string pad_val_string = tp[1].is_none() ? "" : ToString(tp[1]);
         CHECK_FAIL_RETURN_UNEXPECTED(
-          Tensor::CreateTensor(&pad_val, std::vector<std::string>{pad_val_string}, TensorShape::CreateScalar()),
+          Tensor::CreateFromVector(std::vector<std::string>{pad_val_string}, TensorShape::CreateScalar(), &pad_val),
           "Cannot create pad_value Tensor");
       } else {
         float pad_val_float = tp[1].is_none() ? 0 : ToFloat(tp[1]);
-        CHECK_FAIL_RETURN_UNEXPECTED(Tensor::CreateTensor(&pad_val, TensorImpl::kFlexible, TensorShape::CreateScalar(),
+        CHECK_FAIL_RETURN_UNEXPECTED(
-                                                          DataType(DataType::DE_FLOAT32)),
+          Tensor::CreateEmpty(TensorShape::CreateScalar(), DataType(DataType::DE_FLOAT32), &pad_val),
-                                     "Cannot create pad_value Tensor");
+          "Cannot create pad_value Tensor");
         pad_val->SetItemAt<float>({}, pad_val_float);
       }
       (void)pad_info->insert({ToString(p.first), {shape, pad_val}});

mindspore/ccsrc/minddata/dataset/api/python_bindings.cc

@@ -340,7 +340,7 @@ void bindTensor(py::module *m) {
   (void)py::class_<Tensor, std::shared_ptr<Tensor>>(*m, "Tensor", py::buffer_protocol())
     .def(py::init([](py::array arr) {
       std::shared_ptr<Tensor> out;
-      THROW_IF_ERROR(Tensor::CreateTensor(&out, arr));
+      THROW_IF_ERROR(Tensor::CreateFromNpArray(arr, &out));
       return out;
     }))
     .def_buffer([](Tensor &tensor) {
@@ -364,7 +364,18 @@ void bindTensor(py::module *m) {
     });
 
   (void)py::class_<TensorShape>(*m, "TensorShape")
-    .def(py::init<py::list>())
+    .def(py::init([](const py::list &list) {
+      std::vector<dsize_t> list_c;
+      for (auto &i : list) {
+        if (!i.is_none()) {
+          list_c.push_back(i.cast<int>());
+        } else {
+          list_c.push_back(TensorShape::kDimUnknown);
+        }
+      }
+      TensorShape out(list_c);
+      return out;
+    }))
     .def("__str__", &TensorShape::ToString)
     .def("as_list", &TensorShape::AsPyList)
     .def("is_known", &TensorShape::known);

mindspore/ccsrc/minddata/dataset/core/cv_tensor.cc

@@ -23,18 +23,35 @@
 
 namespace mindspore {
 namespace dataset {
-CVTensor::CVTensor(const TensorShape &shape, const DataType &type) : Tensor(shape, type) {
-  (void)this->MatInit(GetMutableBuffer(), shape_, type_, &mat_);
-}
-
-CVTensor::CVTensor(const TensorShape &shape, const DataType &type, const uchar *data) : Tensor(shape, type, data) {
-  (void)this->MatInit(GetMutableBuffer(), shape_, type_, &mat_);
-}
 
 CVTensor::CVTensor(std::shared_ptr<Tensor> tensor) : Tensor(std::move(*tensor)) {
   (void)this->MatInit(GetMutableBuffer(), shape_, type_, &mat_);
 }
 
+Status CVTensor::CreateEmpty(const TensorShape &shape, DataType type, CVTensorPtr *out) {
+  const CVTensorAlloc *alloc = GlobalContext::Instance()->cv_tensor_allocator();
+  *out = std::allocate_shared<CVTensor>(*alloc, shape, type);
+  int64_t byte_size = (*out)->SizeInBytes();
+  // Don't allocate if we have a tensor with no elements.
+  if (byte_size != 0) {
+    RETURN_IF_NOT_OK((*out)->AllocateBuffer(byte_size));
+  }
+
+  return (*out)->MatInit((*out)->GetMutableBuffer(), (*out)->shape_, (*out)->type_, &(*out)->mat_);
+}
+
+Status CVTensor::CreateFromMat(const cv::Mat &mat, CVTensorPtr *out) {
+  TensorPtr out_tensor;
+  cv::Mat mat_local = mat;
+  // if the input Mat's memory is not continuous, copy it to one block of memory
+  if (!mat.isContinuous()) mat_local = mat.clone();
+  TensorShape shape(mat.size, mat_local.type());
+  DataType type = DataType::FromCVType(mat_local.type());
+  RETURN_IF_NOT_OK(CreateFromMemory(shape, type, mat_local.data, &out_tensor));
+  *out = AsCVTensor(out_tensor);
+  return Status::OK();
+}
+
 std::pair<std::array<int, 2>, int> CVTensor::IsValidImage(const TensorShape &shape, const DataType &type) {
   std::array<int, 2> size = {1, 1};
   if (shape.Rank() <= 2 || (shape.Rank() == 3 && shape[2] <= CV_CN_MAX)) {
@@ -57,7 +74,8 @@ std::shared_ptr<CVTensor> CVTensor::AsCVTensor(std::shared_ptr<Tensor> t) {
   if (cv_t != nullptr) {
     return cv_t;
   } else {
-    return std::make_shared<CVTensor>(t);
+    const CVTensorAlloc *alloc = GlobalContext::Instance()->cv_tensor_allocator();
+    return std::allocate_shared<CVTensor>(*alloc, t);
   }
 }
 
@@ -97,5 +115,13 @@ void CVTensor::Squeeze() {
   Tensor::Squeeze();
   (void)this->MatInit(GetMutableBuffer(), shape_, type_, &mat_);
 }
+
+Status CVTensor::MatAtIndex(const std::vector<dsize_t> &index, cv::Mat *mat) {
+  uchar *start = nullptr;
+  TensorShape remaining({-1});
+  RETURN_IF_NOT_OK(this->StartAddrOfIndex(index, &start, &remaining));
+  RETURN_IF_NOT_OK(this->MatInit(start, remaining, type_, mat));
+  return Status::OK();
+}
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/core/cv_tensor.h

@@ -30,56 +30,60 @@
 
 namespace mindspore {
 namespace dataset {
+using CVTensorPtr = std::shared_ptr<CVTensor>;
 class CVTensor : public Tensor {
  public:
-  // Create an empty CVTensor of shape `shape` and type `type`.
+  // Inherit Tensor's constructors
-  // @note The shape and type information should be known and valid.
+  using Tensor::Tensor;
-  // @param shape TensorShape
-  // @param type DataType
-  CVTensor(const TensorShape &shape, const DataType &type);
 
-  // Create a CVTensor from a given buffer, shape and type.
+  /// Create a CVTensor from a given tensor. This constructor should not be used directly, use Create* instead.
-  // @note This constructor allocates a new space in the memory and copies the buffer into it.
+  /// The input tensor will be invalidated (i.e., the shape and type will be
-  // @note The buffer should be valid and the shape and type information should be known and valid.
+  /// set to unknown and the data buffer will point to null.
-  // @param shape TensorShape
+  /// \note there is no memory copying here, the buffer will be assigned to the constructed tensor.
-  // @param type DataType
+  /// \param tensor
-  // @param data unsigned char*, pointer to the data.
-  CVTensor(const TensorShape &shape, const DataType &type, const uchar *data);
-
-  // Create a CVTensor from a given CV::Mat.
-  // @note This constructor allocates a new space in the memory and copies the CV::Mat buffer into it.
-  // @param mat CV::Mat
-  explicit CVTensor(const cv::Mat &mat)
-      : CVTensor(TensorShape(mat.size, mat.type()), DataType::FromCVType(mat.type()), mat.data) {}
-
-  ~CVTensor() = default;
-
-  // Static function to cast a given Tensor as CVTensor. If the input tensor is already of type CVTensor,
-  // this function would be treated as a no-op. Fot other tensor types, a new CVTensor is created based on the data
-  // provided. The Passed Tensor will be invalidated.
-  // @note there is no memory copying here, the buffer will be assigned to the constructed tensor.
-  // @param tensor
-  // @return CVTensor
-  static std::shared_ptr<CVTensor> AsCVTensor(std::shared_ptr<Tensor> tensor);
-
-  // Create a CVTensor from a given tensor. The input tensor will be invalidated (i.e., the shape and type will be
-  // set to unknown and the data buffer will point to null.
-  // @note there is no memory copying here, the buffer will be assigned to the constructed tensor.
-  // @param tensor
   explicit CVTensor(std::shared_ptr<Tensor> tensor);
 
-  // Getter function for the CV::Mat
+  /// Create CV tensor with type and shape. Items of the tensor would be uninitialized.
-  // @return
+  /// \param shape [in] shape of the output tensor
+  /// \param type [in] type of the output tensor
+  /// \param out [out] Generated tensor
+  /// \return Status code
+  static Status CreateEmpty(const TensorShape &shape, DataType type, CVTensorPtr *out);
+
+  /// Create CV tensor from cv::Mat
+  /// \note This constructor allocates a new space in the memory and copies the CV::Mat buffer into it.
+  /// \param mat [in] cv::Mat to be copied into the new tensor.
+  /// \param out [out] Generated tensor
+  /// \return Status code
+  static Status CreateFromMat(const cv::Mat &mat, CVTensorPtr *out);
+
+  ~CVTensor() override = default;
+
+  /// Static function to cast a given Tensor as CVTensor. If the input tensor is already of type CVTensor,
+  /// this function would be treated as a no-op. Fot other tensor types, a new CVTensor is created based on the data
+  /// provided. The Passed Tensor will be invalidated.
+  /// \note the input tensor will be invalidated.
+  /// \note there is no memory copying here, the buffer will be assigned to the constructed tensor.
+  /// \param tensor [in]
+  /// \return CVTensor
+  static std::shared_ptr<CVTensor> AsCVTensor(std::shared_ptr<Tensor> tensor);
+
+  /// Get a reference to the CV::Mat
+  /// \return a reference to the internal CV::Mat
   cv::Mat mat() const { return mat_; }
 
-  // Static function to check if the passed information (shape and type) can be treated as a valid description
+  /// Get a copy of the CV::Mat
-  // of an image in OpenCV. Moreover, it returns OpenCV shape and type
+  /// \return a copy of internal CV::Mat
-  // For example, if the shape is <512,512,3> and type is DE_UINT8, the output would be [512,512] and CV_8UC3.
+  cv::Mat matCopy() const { return mat_.clone(); }
-  // In case of invalid shape or type, the function will return pair<null,0>
+
-  // @param shape TensorShape
+  /// Static function to check if the passed information (shape and type) can be treated as a valid description
-  // @param type DataType
+  /// of an image in OpenCV. Moreover, it returns OpenCV shape and type
-  // @return std::pair of OpenCV shape and type
+  /// For example, if the shape is <512,512,3> and type is DE_UINT8, the output would be [512,512] and CV_8UC3.
-  std::pair<std::array<int, 2>, int> IsValidImage(const TensorShape &shape, const DataType &type);
+  /// In case of invalid shape or type, the function will return pair<null,0>
+  /// \param shape [in] TensorShape
+  /// \param type [in] DataType
+  /// \return std::pair of OpenCV shape and type
+  static std::pair<std::array<int, 2>, int> IsValidImage(const TensorShape &shape, const DataType &type);
 
   Status Reshape(const TensorShape &shape) override;
 
@@ -87,18 +91,19 @@ class CVTensor : public Tensor {
 
   void Squeeze() override;
 
-  Status Mat(const std::vector<dsize_t> &index, cv::Mat *mat) {
+  Status MatAtIndex(const std::vector<dsize_t> &index, cv::Mat *mat);
-    uchar *start = nullptr;
-    TensorShape remaining({-1});
-    RETURN_IF_NOT_OK(this->StartAddrOfIndex(index, &start, &remaining));
-    RETURN_IF_NOT_OK(this->MatInit(start, remaining, type_, mat));
-    return Status::OK();
-  }
 
  private:
+  /// Opencv Mat object wrapping the raw data of the tensor.
+  /// Modifying the content of the matrix, modifies the tensor.
   cv::Mat mat_;
 
-  // Initialize CV::Mat with the data_, shape_ and type_
+  /// Create cv::Mat from data, TensorShape and DataType
+  /// \param data [in] Pointer to the data in memory.
+  /// \param shape [in] Shape of the tensor.
+  /// \param type [in] Type of the tensor.
+  /// \param mat [out] cv::Mat initialized with the provided data.
+  /// \return Status code
   Status MatInit(uchar *data, const TensorShape &shape, const DataType &type, cv::Mat *mat);
 };
 }  // namespace dataset

mindspore/ccsrc/minddata/dataset/core/data_type.h

@@ -284,6 +284,11 @@ inline DataType DataType::FromCType<std::string_view>() {
   return DataType(DataType::DE_STRING);
 }
 
+template <>
+inline DataType DataType::FromCType<std::string>() {
+  return DataType(DataType::DE_STRING);
+}
+
 template <>
 inline bool DataType::IsLooselyCompatible<bool>() const {
   return type_ == DataType::DE_BOOL;

mindspore/ccsrc/minddata/dataset/core/tensor.cc

@@ -59,49 +59,11 @@ Tensor::Tensor(const TensorShape &shape, const DataType &type) : shape_(shape),
   data_allocator_ = std::make_unique<Allocator<unsigned char>>(global_pool);
 }
 
-Tensor::Tensor(const TensorShape &shape, const DataType &type, const unsigned char *data) : Tensor(shape, type) {
-  if (type.IsNumeric()) {
-    // If the data pointer was given, then we can also populate the tensor with data
-    if (data != nullptr) {
-      // Given the shape/type of this tensor, compute the data size and copy in the input bytes.
-      int64_t byte_size = this->SizeInBytes();
-      Status s = this->AllocateBuffer(byte_size);  // Allocates data_ inside itself
-      if (s.IsOk() && data_ != nullptr) {
-        int ret_code = memcpy_s(data_, byte_size, data, byte_size);
-        if (ret_code != 0) {
-          MS_LOG(ERROR) << "Failed to copy data into Tensor!";
-        }
-      } else {
-        MS_LOG(ERROR) << "Failed to create memory for Tensor!";
-      }
-    }
-  } else {
-    MS_LOG(ERROR) << "Type should be numeric to use this constructor.";
-  }
-}
-
-Tensor::Tensor(const TensorShape &shape, const DataType &type, const unsigned char *data, const dsize_t &length)
-    : Tensor(shape, type) {
-  // If the data pointer was given, then we can also populate the tensor with data
-  if (data != nullptr) {
-    // Allocates data_ inside itself
-    Status s = AllocateBuffer(length);
-    if (s.IsError()) {
-      MS_LOG(ERROR) << "Failed to create memory for Tensor!";
-    }
-    if (data_ != nullptr) {
-      int ret_code = memcpy_s(data_, length, data, length);
-      if (ret_code != 0) {
-        MS_LOG(ERROR) << "Failed to copy data into Tensor!";
-      }
-    }
-  }
-}
-
 Tensor::Tensor(Tensor &&other) noexcept
     : shape_(other.shape()),
       type_(other.type()),
       data_(other.GetMutableBuffer()),
+      data_end_(other.data_end_),
       data_allocator_(std::move(other.data_allocator_)) {
   other.Invalidate();
 }
@@ -117,118 +79,61 @@ Tensor &Tensor::operator=(Tensor &&other) noexcept {
   }
   return *this;
 }
-
+Status Tensor::CreateEmpty(const TensorShape &shape, const DataType &type, TensorPtr *out) {
-Tensor::Tensor(const std::vector<std::string> &strings, const TensorShape &shape)
+  CHECK_FAIL_RETURN_UNEXPECTED(shape.known(), "Invalid shape.");
-    : Tensor(TensorShape({static_cast<dsize_t>(strings.size())}), DataType(DataType::DE_STRING)) {
+  CHECK_FAIL_RETURN_UNEXPECTED(type != DataType::DE_UNKNOWN, "Invalid data type.");
-  auto length_sum = [](dsize_t sum, const std::string &s) { return s.length() + sum; };
+  const TensorAlloc *alloc = GlobalContext::Instance()->tensor_allocator();
-  dsize_t total_length = std::accumulate(strings.begin(), strings.end(), 0, length_sum);
+  *out = std::allocate_shared<Tensor>(*alloc, shape, type);
-
+  // if it's a string tensor and it has no elements, Just initialize the shape and type.
-  // total bytes needed = offset array + strings
+  if (!type.IsNumeric() && shape.NumOfElements() == 0) {
-  // offset array needs to store one offset var per element + 1 extra to get the length of the last string.
+    return Status::OK();
-  // strings will be null-terminated --> need 1 extra byte per element
-  dsize_t num_bytes = (kOffsetSize + 1) * shape_.NumOfElements() + kOffsetSize + total_length;
-
-  data_ = data_allocator_->allocate(num_bytes);
-
-  auto offset_arr = reinterpret_cast<offset_t *>(data_);
-  uchar *buf = GetStringsBuffer();
-
-  offset_t offset = buf - data_;  // the first string will start here
-  uint32_t i = 0;
-  for (const auto &str : strings) {
-    //  insert the start index of the string.
-    offset_arr[i++] = offset;
-    // total bytes are reduced by kOffsetSize
-    num_bytes -= kOffsetSize;
-    // insert actual string
-    int ret_code = memcpy_s(data_ + offset, num_bytes, common::SafeCStr(str), str.length() + 1);
-    if (ret_code != 0) MS_LOG(ERROR) << "Cannot copy string into Tensor";
-    //  next string will be stored right after the current one.
-    offset = offset + str.length() + 1;
-    // total bytes are reduced by the length of the string
-    num_bytes -= str.length() + 1;
   }
-  // store one more offset value so we can get the length of the last string
-  // length[last_element] = offset_arr[last_element + 1] - offset_arr[last_element]
-  offset_arr[i] = offset;
 
-  this->data_end_ = data_ + offset_arr[i];
+  CHECK_FAIL_RETURN_UNEXPECTED(type.IsNumeric(), "Number of elements is not 0. The type should be numeric.");
 
-  MS_ASSERT(num_bytes == 0);
+  int64_t byte_size = (*out)->SizeInBytes();
-  if (shape.known()) Tensor::Reshape(shape);
+  // Don't allocate if we have a tensor with no elements.
+  if (byte_size != 0) {
+    RETURN_IF_NOT_OK((*out)->AllocateBuffer(byte_size));
+  }
+
+  return Status::OK();
+}
+Status Tensor::CreateFromMemory(const TensorShape &shape, const DataType &type, const uchar *src, TensorPtr *out) {
+  RETURN_IF_NOT_OK(CreateEmpty(shape, type, out));
+  if (src != nullptr) {
+    // Given the shape/type of this tensor, compute the data size and copy in the input bytes.
+    int64_t byte_size = (*out)->SizeInBytes();
+    int ret_code = memcpy_s((*out)->data_, byte_size, src, byte_size);
+    CHECK_FAIL_RETURN_UNEXPECTED(ret_code == 0, "Failed to copy data into tensor.");
+  }
+  return Status::OK();
 }
 
-Tensor::Tensor(const dataengine::BytesList &bytes_list, const TensorShape &shape)
+Status Tensor::CreateFromMemory(const TensorShape &shape, const DataType &type, const unsigned char *src,
-    : Tensor(TensorShape({static_cast<dsize_t>(bytes_list.value_size())}), DataType(DataType::DE_STRING)) {
+                                const dsize_t &length, TensorPtr *out) {
-  // total bytes needed = offset array + strings
+  CHECK_FAIL_RETURN_UNEXPECTED(src != nullptr, "Pointer to source data is null.");
-  // offset array needs to store one offset var per element + 1 extra to get the length of the last string.
+  const TensorAlloc *alloc = GlobalContext::Instance()->tensor_allocator();
-  // strings will be null-terminated --> need 1 extra byte per element
+  *out = std::allocate_shared<Tensor>(*alloc, shape, type);
-  dsize_t num_bytes = (kOffsetSize)*shape_.NumOfElements() + kOffsetSize + bytes_list.ByteSizeLong();
+  if (type.IsNumeric()) {
-
+    dsize_t calculated_length = (*out)->SizeInBytes();
-  data_ = data_allocator_->allocate(num_bytes);
+    CHECK_FAIL_RETURN_UNEXPECTED(calculated_length == length, "Length of source data does not match the shape.");
-
+  } else {
-  auto offset_arr = reinterpret_cast<offset_t *>(data_);
+    // min_length is the length of a tensor with empty strings
-  uchar *buf = GetStringsBuffer();
+    // min_length = the number of bytes needed to store the offsets + 1 byte for each element
-
+    dsize_t min_length = (shape.NumOfElements() + 1) * kOffsetSize + shape.NumOfElements();
-  offset_t offset = buf - data_;  // the first string will start here
+    CHECK_FAIL_RETURN_UNEXPECTED(min_length <= length, "Length of source data does not match the shape.");
-  uint32_t i = 0;
-  for (; i < bytes_list.value_size(); i++) {
-    const std::string &str = bytes_list.value(i);
-    //  insert the start index of the string.
-    offset_arr[i] = offset;
-    // total bytes are reduced by kOffsetSize
-    num_bytes -= kOffsetSize;
-    // insert actual string
-    int ret_code = memcpy_s(data_ + offset, num_bytes, common::SafeCStr(str), str.length() + 1);
-    if (ret_code != 0) {
-      MS_LOG(ERROR) << "Cannot copy string into Tensor";
-    }
-    //  next string will be stored right after the current one.
-    offset = offset + str.length() + 1;
-    // total bytes are reduced by the length of the string
-    num_bytes -= str.length() + 1;
-  }
-  // store one more offset value so we can get the length of the last string
-  // length[last_element] = offset_arr[last_element + 1] - offset_arr[last_element]
-  offset_arr[i] = offset;
-
-  data_end_ = data_ + offset_arr[i];
-
-  MS_ASSERT(num_bytes == 0);
-  if (shape.known()) Tensor::Reshape(shape);
-}
-
-Status Tensor::CreateTensor(std::shared_ptr<Tensor> *ptr, TensorImpl tensor_impl, const TensorShape &shape,
-                            DataType type, const unsigned char *data) {
-  if (!shape.known()) {
-    RETURN_STATUS_UNEXPECTED("Invalid shape.");
-  }
-  if (type == DataType::DE_UNKNOWN) {
-    RETURN_STATUS_UNEXPECTED("Invalid data type.");
   }
 
-  switch (tensor_impl) {
+  RETURN_IF_NOT_OK((*out)->AllocateBuffer(length));
-    case TensorImpl::kFlexible: {
+  int ret_code = memcpy_s((*out)->data_, length, src, length);
-      // The flex tensor is really just the base class tensor implementation
+  CHECK_FAIL_RETURN_UNEXPECTED(ret_code == 0, "Failed to copy data into tensor.");
-      const TensorAlloc *alloc = GlobalContext::Instance()->tensor_allocator();
+
-      *ptr = std::allocate_shared<Tensor>(*alloc, shape, type, data);
+  return Status::OK();
-      break;
-    }
-    case TensorImpl::kCv: {
-      const CVTensorAlloc *alloc = GlobalContext::Instance()->cv_tensor_allocator();
-      *ptr = std::allocate_shared<CVTensor>(*alloc, shape, type, data);
-      break;
-    }
-    default: {
-      std::string err_msg("Invalid tensor implementation type.");
-      RETURN_STATUS_UNEXPECTED(err_msg);
-    }
-  }
-  return Status::OK();  // returns base-class shared_ptr
 }
 
 #ifdef ENABLE_PYTHON
-Status Tensor::CreateTensorFromNumpyString(std::shared_ptr<Tensor> *ptr, py::array arr) {
+Status Tensor::CreateFromNpString(py::array arr, std::shared_ptr<Tensor> *out) {
   std::vector<dsize_t> shape;
   for (dsize_t i = 0; i < arr.ndim(); i++) {
     shape.push_back(static_cast<dsize_t>(arr.shape()[i]));
@@ -244,34 +149,38 @@ Status Tensor::CreateTensorFromNumpyString(std::shared_ptr<Tensor> *ptr, py::arr
 
   arr.resize(shape);  // resize arr back to the original shape
 
-  return CreateTensor(ptr, strings, TensorShape{shape});
+  return CreateFromVector(strings, TensorShape{shape}, out);
 }
 
-Status Tensor::CreateTensor(std::shared_ptr<Tensor> *ptr, py::array arr) {
+Status Tensor::CreateFromNpArray(const py::array &arr, std::shared_ptr<Tensor> *out) {
   if (DataType::FromNpArray(arr) == DataType::DE_STRING) {
-    return CreateTensorFromNumpyString(ptr, arr);
+    return CreateFromNpString(arr, out);
   }
   const TensorAlloc *alloc = GlobalContext::Instance()->tensor_allocator();
-  *ptr = std::allocate_shared<Tensor>(*alloc, TensorShape({}), DataType(DataType::DE_UNKNOWN));
+  *out = std::allocate_shared<Tensor>(*alloc, TensorShape::CreateScalar(), DataType(DataType::DE_UNKNOWN));
 
   std::vector<dsize_t> shape;
   for (dsize_t i = 0; i < arr.ndim(); i++) {
     shape.push_back(static_cast<dsize_t>(arr.shape()[i]));
   }
 
-  (*ptr)->shape_ = TensorShape(shape);
+  (*out)->shape_ = TensorShape(shape);
-  (*ptr)->type_ = DataType::FromNpArray(arr);
+  (*out)->type_ = DataType::FromNpArray(arr);
-  if (!(*ptr)->shape_.known()) RETURN_STATUS_UNEXPECTED("Invalid shape.");
+  if (!(*out)->shape_.known()) RETURN_STATUS_UNEXPECTED("Invalid shape.");
 
-  if ((*ptr)->type_ == DataType::DE_UNKNOWN) RETURN_STATUS_UNEXPECTED("Invalid data type.");
+  if ((*out)->type_ == DataType::DE_UNKNOWN) RETURN_STATUS_UNEXPECTED("Invalid data type.");
 
   std::shared_ptr<MemoryPool> global_pool = GlobalContext::Instance()->mem_pool();
-  (*ptr)->data_allocator_ = std::make_unique<Allocator<unsigned char>>(global_pool);
+  (*out)->data_allocator_ = std::make_unique<Allocator<unsigned char>>(global_pool);
-  int64_t byte_size = (*ptr)->SizeInBytes();
+  int64_t byte_size = (*out)->SizeInBytes();
-  RETURN_IF_NOT_OK((*ptr)->AllocateBuffer(byte_size));
+  if (byte_size == 0) {
+    return Status::OK();
+  }
+
+  RETURN_IF_NOT_OK((*out)->AllocateBuffer(byte_size));
 
   unsigned char *data = static_cast<unsigned char *>(arr.request().ptr);
-  if ((*ptr)->data_ == nullptr) {
+  if ((*out)->data_ == nullptr) {
     RETURN_STATUS_UNEXPECTED("Failed to create memory for Tensor.");
   }
 
@@ -282,61 +191,89 @@ Status Tensor::CreateTensor(std::shared_ptr<Tensor> *ptr, py::array arr) {
 
   // check if strides are contiguous
   bool is_strided = false;
-  dsize_t count = (*ptr)->shape_.NumOfElements();
+  dsize_t count = (*out)->shape_.NumOfElements();
   for (size_t i = 0; i < shape.size(); i++) {
     count /= shape[i];
-    if (strides[i] != (*ptr)->type_.SizeInBytes() * count) {
+    if (strides[i] != (*out)->type_.SizeInBytes() * count) {
       is_strided = true;
       break;
     }
   }
 
   if (is_strided) {
-    RETURN_IF_NOT_OK(CopyStridedArray((*ptr)->data_, data, shape, strides, (*ptr)->type_.SizeInBytes()));
+    RETURN_IF_NOT_OK(CopyStridedArray((*out)->data_, data, shape, strides, (*out)->type_.SizeInBytes()));
   } else {
-    int ret_code = memcpy_s((*ptr)->data_, byte_size, data, byte_size);
+    int ret_code = memcpy_s((*out)->data_, byte_size, data, byte_size);
     if (ret_code != 0) {
       RETURN_STATUS_UNEXPECTED("Failed to copy data into Tensor.");
     }
   }
 
-  return Status::OK();  // returns base-class shared_ptr
+  return Status::OK();
 }
 #endif
 
-Status Tensor::CreateTensor(std::shared_ptr<Tensor> *ptr, const std::vector<std::string> &strings,
+Status Tensor::CreateFromByteList(const dataengine::BytesList &bytes_list, const TensorShape &shape, TensorPtr *out) {
-                            const TensorShape &shape) {
   const TensorAlloc *alloc = GlobalContext::Instance()->tensor_allocator();
-  *ptr = std::allocate_shared<Tensor>(*alloc, strings, shape);
+  *out = std::allocate_shared<Tensor>(*alloc, TensorShape({static_cast<dsize_t>(bytes_list.value_size())}),
+                                      DataType(DataType::DE_STRING));
+  // total bytes needed = offset array + strings
+  // offset array needs to store one offset var per element + 1 extra to get the length of the last string.
+  // strings will be null-terminated --> need 1 extra byte per element
+  dsize_t num_bytes = (kOffsetSize) * (*out)->shape_.NumOfElements() + kOffsetSize + bytes_list.ByteSizeLong();
+
+  (*out)->data_ = (*out)->data_allocator_->allocate(num_bytes);
+
+  auto offset_arr = reinterpret_cast<offset_t *>((*out)->data_);
+  uchar *buf = (*out)->GetStringsBuffer();
+
+  offset_t offset = buf - (*out)->data_;  // the first string will start here
+  uint32_t i = 0;
+  for (; i < bytes_list.value_size(); i++) {
+    const std::string &str = bytes_list.value(i);
+    //  insert the start index of the string.
+    offset_arr[i] = offset;
+    // total bytes are reduced by kOffsetSize
+    num_bytes -= kOffsetSize;
+    // insert actual string
+    int ret_code = memcpy_s((*out)->data_ + offset, num_bytes, common::SafeCStr(str), str.length() + 1);
+    if (ret_code != 0) {
+      MS_LOG(ERROR) << "Cannot copy string into Tensor";
+    }
+    //  next string will be stored right after the current one.
+    offset = offset + str.length() + 1;
+    // total bytes are reduced by the length of the string
+    num_bytes -= str.length() + 1;
+  }
+  // store one more offset value so we can get the length of the last string
+  // length[last_element] = offset_arr[last_element + 1] - offset_arr[last_element]
+  offset_arr[i] = offset;
+
+  (*out)->data_end_ = (*out)->data_ + offset_arr[i];
+
+  MS_ASSERT(num_bytes == 0);
+  (*out)->Reshape(shape);
   return Status::OK();
 }
 
-Status Tensor::CreateTensor(std::shared_ptr<Tensor> *ptr, const dataengine::BytesList &bytes_list,
+Status Tensor::CreateFromFile(const std::string &path, std::shared_ptr<Tensor> *out) {
-                            const TensorShape &shape) {
-  const TensorAlloc *alloc = GlobalContext::Instance()->tensor_allocator();
-  *ptr = std::allocate_shared<Tensor>(*alloc, bytes_list, shape);
-  return Status::OK();
-}
-
-Status Tensor::CreateTensor(std::shared_ptr<Tensor> *ptr, const std::string &file_path) {
   std::ifstream fs;
-  fs.open(file_path, std::ios::binary | std::ios::in);
+  fs.open(path, std::ios::binary | std::ios::in);
-  CHECK_FAIL_RETURN_UNEXPECTED(!fs.fail(), "Fail to open file: " + file_path);
+  CHECK_FAIL_RETURN_UNEXPECTED(!fs.fail(), "Fail to open file: " + path);
   int64_t num_bytes = fs.seekg(0, std::ios::end).tellg();
   CHECK_FAIL_RETURN_UNEXPECTED(fs.seekg(0, std::ios::beg).good(), "Fail to find size of file");
-  RETURN_IF_NOT_OK(
+  RETURN_IF_NOT_OK(Tensor::CreateEmpty(TensorShape{num_bytes}, DataType(DataType::DE_UINT8), out));
-    Tensor::CreateTensor(ptr, TensorImpl::kFlexible, TensorShape{num_bytes}, DataType(DataType::DE_UINT8)));
+  int64_t written_bytes = fs.read(reinterpret_cast<char *>((*out)->GetMutableBuffer()), num_bytes).gcount();
-  int64_t written_bytes = fs.read(reinterpret_cast<char *>((*ptr)->GetMutableBuffer()), num_bytes).gcount();
   CHECK_FAIL_RETURN_UNEXPECTED(written_bytes == num_bytes && fs.good(), "Error in writing to tensor");
   fs.close();
   return Status::OK();
 }
 
-Status Tensor::CreateTensor(std::shared_ptr<Tensor> *ptr, const dataengine::BytesList &bytes_list,
+Status Tensor::CreateFromByteList(const dataengine::BytesList &bytes_list, const TensorShape &shape,
-                            const TensorShape &shape, const DataType &type, dsize_t pad_size) {
+                                  const DataType &type, dsize_t pad_size, TensorPtr *out) {
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(ptr, TensorImpl::kFlexible, shape, type));
+  RETURN_IF_NOT_OK(Tensor::CreateEmpty(shape, type, out));
 
-  unsigned char *current_tensor_addr = (*ptr)->GetMutableBuffer();
+  unsigned char *current_tensor_addr = (*out)->GetMutableBuffer();
   int64_t tensor_bytes_remaining = bytes_list.value_size() * pad_size;
 
   for (int i = 0; i < bytes_list.value_size(); i++) {
@@ -368,7 +305,7 @@ Status Tensor::CreateTensor(std::shared_ptr<Tensor> *ptr, const dataengine::Byte
 // Here we convert array C to array A, by memcpy index by index (Note that not all elements in C is copied)
 Status Tensor::CopyStridedArray(unsigned char *dst, unsigned char *src, std::vector<dsize_t> shape,
                                 std::vector<dsize_t> strides, uint8_t type_size) {
-  dsize_t size = std::accumulate(shape.begin(), shape.end(), 1, std::multiplies<dsize_t>());
+  dsize_t size = std::accumulate(shape.begin(), shape.end(), 1, std::multiplies<>());
   for (dsize_t i = 0; i < size; ++i) {
     dsize_t offset = 0;
     dsize_t count = i;
@@ -429,29 +366,29 @@ void Tensor::PrintItemAt(const std::vector<dsize_t> &index, std::ostream &out) c
   MS_ASSERT(data_);
 
   switch (type_.value()) {
-    CASE_PRINT_HEX(DataType::DE_BOOL, bool);
+    CASE_PRINT_HEX(DataType::DE_BOOL, bool)
 
-    CASE_PRINT_HEX(DataType::DE_INT8, int8_t);
+    CASE_PRINT_HEX(DataType::DE_INT8, int8_t)
 
-    CASE_PRINT_HEX(DataType::DE_UINT8, uint8_t);
+    CASE_PRINT_HEX(DataType::DE_UINT8, uint8_t)
 
-    CASE_PRINT(DataType::DE_INT16, int16_t);
+    CASE_PRINT(DataType::DE_INT16, int16_t)
 
-    CASE_PRINT(DataType::DE_UINT16, uint16_t);
+    CASE_PRINT(DataType::DE_UINT16, uint16_t)
 
-    CASE_PRINT(DataType::DE_INT32, int32_t);
+    CASE_PRINT(DataType::DE_INT32, int32_t)
 
-    CASE_PRINT(DataType::DE_UINT32, uint32_t);
+    CASE_PRINT(DataType::DE_UINT32, uint32_t)
 
-    CASE_PRINT(DataType::DE_INT64, int64_t);
+    CASE_PRINT(DataType::DE_INT64, int64_t)
 
-    CASE_PRINT(DataType::DE_UINT64, uint64_t);
+    CASE_PRINT(DataType::DE_UINT64, uint64_t)
 
-    CASE_PRINT(DataType::DE_FLOAT16, float16);
+    CASE_PRINT(DataType::DE_FLOAT16, float16)
 
-    CASE_PRINT(DataType::DE_FLOAT32, float);
+    CASE_PRINT(DataType::DE_FLOAT32, float)
 
-    CASE_PRINT(DataType::DE_FLOAT64, double);
+    CASE_PRINT(DataType::DE_FLOAT64, double)
 
     case DataType::DE_STRING: {
       std::string_view o{""};
@@ -501,50 +438,14 @@ void Tensor::Print(std::ostream &out) const {
   }
 }
 Status Tensor::AllocateBuffer(const dsize_t &length) {
+  RETURN_UNEXPECTED_IF_NULL(data_allocator_);
   if (data_ == nullptr) {
-    if (data_allocator_ != nullptr) {
+    data_ = data_allocator_->allocate(length);
-      data_ = data_allocator_->allocate(length);
+    CHECK_FAIL_RETURN_UNEXPECTED(data_ != nullptr, "Failed to allocate memory for tensor.");
-      RETURN_UNEXPECTED_IF_NULL(data_);
+    data_end_ = data_ + length;
-      data_end_ = data_ + length;
-    } else {
-      data_ = static_cast<unsigned char *>(malloc(length));
-      data_end_ = data_ + length;
-      RETURN_UNEXPECTED_IF_NULL(data_);
-    }
   }
   return Status::OK();
 }
-const unsigned char *Tensor::GetBuffer() const {
-  // This version cannot modify anything.  data_ could possibly be null.
-  return data_;
-}
-
-// check for empty
-bool Tensor::HasData() const {
-  if (data_ == nullptr) {
-    return true;
-  } else {
-    return false;
-  }
-}
-
-unsigned char *Tensor::GetMutableBuffer() {
-  if (!shape_.known() || type_ == DataType::DE_UNKNOWN) {
-    return nullptr;
-  }
-  // If the data area is already created, return the pointer to it
-  if (data_ != nullptr) {
-    return data_;
-  } else {
-    // If the data area is not created, then identify the memory size based
-    // on the shape and type and allocate it.
-    if (this->AllocateBuffer(this->SizeInBytes()).IsOk()) {
-      return data_;
-    } else {
-      return nullptr;
-    }
-  }
-}
 
 Status Tensor::Reshape(const TensorShape &shape) {
   if (shape.NumOfElements() == shape_.NumOfElements()) {
@@ -628,7 +529,7 @@ Status Tensor::InsertTensor(const std::vector<dsize_t> &ind, const std::shared_p
   err_msg += (ind.size() + tensor->Rank() != this->Rank()) ? "[Tensor] incorrect index\n" : "";
   err_msg += tensor->type().SizeInBytes() != this->type().SizeInBytes() ? "[Tensor] incorrect datatype\n" : "";
   uchar *start_addr_of_ind = nullptr;
-  TensorShape remaining_shape({-1});
+  TensorShape remaining_shape = TensorShape::CreateUnknownRankShape();
   err_msg += (!StartAddrOfIndex(ind, &start_addr_of_ind, &remaining_shape).IsOk()) ? "[Tensor] incorrect index\n" : "";
   err_msg += !(remaining_shape == tensor->shape()) ? "[Tensor] memory error\n" : "";
   if (!err_msg.empty()) {
@@ -697,7 +598,7 @@ Status Tensor::ExpandDim(const dsize_t &axis) {
   return Status::OK();
 }
 
-std::vector<dsize_t> Tensor::Strides() {
+std::vector<dsize_t> Tensor::Strides() const {
   std::vector<dsize_t> strides = shape_.Strides();
   uint8_t size = type_.SizeInBytes();
   std::transform(strides.begin(), strides.end(), strides.begin(), [&size](const auto &c) { return c * size; });
@@ -765,7 +666,6 @@ Status Tensor::GetItemAt(std::string_view *o, const std::vector<dsize_t> &index)
 #ifdef ENABLE_PYTHON
 // return data as numpy, should return status
 Status Tensor::GetDataAsNumpy(py::array *data) {
-  RETURN_UNEXPECTED_IF_NULL(data_);
   RETURN_UNEXPECTED_IF_NULL(data);
   if (type_ == DataType::DE_BOOL) {
     *data = py::array_t<bool>(shape_.AsVector(), reinterpret_cast<bool *>(data_));
@@ -974,7 +874,9 @@ Status Tensor::CopyLastDimAt(const std::shared_ptr<Tensor> &src, const std::vect
 }
 Status Tensor::Slice(std::shared_ptr<Tensor> *out, const std::vector<dsize_t> &indices) {
   CHECK_FAIL_RETURN_UNEXPECTED(shape_.Rank() == 1, "Currently Slice work with rank 1 tensors only.");
-  CHECK_FAIL_RETURN_UNEXPECTED(!indices.empty(), "Indices are empty, generated tensor would be empty.");
+  if (indices.empty()) {
+    return CreateEmpty(TensorShape({0}), type_, out);
+  }
   if (type_.IsNumeric()) {
     return SliceNumeric(out, indices);
   } else {
@@ -982,8 +884,7 @@ Status Tensor::Slice(std::shared_ptr<Tensor> *out, const std::vector<dsize_t> &i
   }
 }
 Status Tensor::SliceNumeric(std::shared_ptr<Tensor> *out, const std::vector<dsize_t> &indices) {
-  RETURN_IF_NOT_OK(
+  RETURN_IF_NOT_OK(CreateEmpty(TensorShape({static_cast<dsize_t>(indices.size())}), type_, out));
-    CreateTensor(out, TensorImpl::kFlexible, TensorShape({static_cast<dsize_t>(indices.size())}), type_));
   (*out)->GetMutableBuffer();
   dsize_t out_index = 0;
   dsize_t dim_length = shape_[0];
@@ -1027,7 +928,7 @@ Status Tensor::SliceString(std::shared_ptr<Tensor> *out, const std::vector<dsize
     GetItemAt(&sv, {cur_index});
     strings.emplace_back(sv);
   }
-  return CreateTensor(out, strings);
+  return CreateFromVector(strings, TensorShape({static_cast<dsize_t>(strings.size())}), out);
 }
 
 }  // namespace dataset

mindspore/ccsrc/minddata/dataset/core/tensor.h

@@ -33,6 +33,7 @@
 #include "pybind11/stl.h"
 #endif
 
+#include "common/utils.h"
 #include "minddata/dataset/core/constants.h"
 #include "minddata/dataset/core/data_type.h"
 #include "minddata/dataset/core/tensor_shape.h"
@@ -50,170 +51,155 @@ class Allocator;
 
 using CharAllocPtr = std::unique_ptr<Allocator<unsigned char>>;
 using TensorAllocPtr = std::shared_ptr<Allocator<Tensor>>;  // An allocator shared_ptr for Tensors
+using offset_t = uint32_t;                                  // type of offset values to store strings locations
+using TensorPtr = std::shared_ptr<Tensor>;
 
 class Tensor {
  public:
   Tensor() = delete;
-
-  // Create a new tensor, does not internally allocate storage. This constructor is protected, use CreateTensor.
-  // @note The shape and type information should be known and valid.
-  // @param shape TensorShape
-  // @param type DataType
-  Tensor(const TensorShape &shape, const DataType &type);
-
-  // Create a new tensor, allocates storage and copies in data. This constructor is protected, use CreateTensor.
-  // @note The buffer should be valid and the shape and type information should be known and valid.
-  // @param shape TensorShape
-  // @param type DataType
-  // @param data unsigned char*, pointer to the data.
-  Tensor(const TensorShape &shape, const DataType &type, const unsigned char *data);
-
-  Tensor(const TensorShape &shape, const DataType &type, const unsigned char *data, const dsize_t &length);
-
   Tensor(const Tensor &other) = delete;
-
   Tensor &operator=(const Tensor &other) = delete;
 
+  /// Create a tensor using shape and type. This constructor should not be used directly, use CreateFromTensor instead
+  /// \note The shape and type information should be known and valid
+  /// \note The constructor does not allocate data
+  /// \param shape TensorShape
+  /// \param type DataType
+  Tensor(const TensorShape &shape, const DataType &type);
+
+  /// Move constructor
+  /// \param other Tensor to be moved
   Tensor(Tensor &&other) noexcept;
 
+  /// Move assigment operator
+  /// \param other Tensor to be moved
   Tensor &operator=(Tensor &&other) noexcept;
 
-  Status AllocateBuffer(const dsize_t &length);
+  /// Create a numeric tensor with type and shape. Items of the tensor would be uninitialized.
+  /// \param[in] shape shape of the output tensor
+  /// \param[in] type type of the output tensor
+  /// \param[out] out Generated tensor
+  /// \return Status code
+  static Status CreateEmpty(const TensorShape &shape, const DataType &type, TensorPtr *out);
 
-  // type of offest values to store strings information
+  /// Create a numeric tensor from a pointer in memory. Length of the source data is determined from the shape and type.
-  using offset_t = uint32_t;
+  /// Data will be copied into the new created tensor.
-  // const of the size of the offset variable
+  /// \param[in] shape shape of the output tensor
-  static constexpr uint8_t kOffsetSize = sizeof(offset_t);
+  /// \param[in] type type of the output tensor
-  // Tensor base class which holds the data in an unsigned char* buffer.
+  /// \param[in] src pointer to the source data
+  /// \param[out] out Generated tensor
+  /// \return Status code
+  static Status CreateFromMemory(const TensorShape &shape, const DataType &type, const uchar *src, TensorPtr *out);
 
-  // Construct  a scalar string Tensor
+  /// Create a tensor from a pointer in memory and length. Data will be copied into the new created tensor.
-  explicit Tensor(const std::string &str) : Tensor(std::vector<std::string>{str}, TensorShape::CreateScalar()) {}
+  /// \param[in] shape shape of the output tensor
+  /// \param[in] type type of the output tensor
+  /// \param[in] src pointer to the source data
+  /// \param[in] length length of the src data
+  /// \param[out] out Generated tensor
+  /// \return Status code
+  static Status CreateFromMemory(const TensorShape &shape, const DataType &type, const uchar *src,
+                                 const dsize_t &length, TensorPtr *out);
 
-  // Construct a tensor from  a list of strings. Reshape the tensor with `shape` if given, otherwise assume the shape is
+  /// Create a copy of the input tensor
-  // the size of the vector `strings`.
+  /// \param[in] in original tensor to be copied
-  // The memory layout of a Tensor of strings consists of the Offset_array followed by the strings.
+  /// \param[out] out output tensor to be generated
-  // Thr offset array will store one extra value to find the length of the last string.
+  /// \return Status
-  // OFFSET1, OFFSET2, ..., OFFSETn+1, STRING1, STRING2, ..., STRINGn
+  static Status CreateFromTensor(const TensorPtr &in, TensorPtr *out) {
-  // The value of each offset is the start index of the corresponding string
+    return CreateFromMemory(in->shape(), in->type(), in->GetBuffer(), in->SizeInBytes(), out);
-  // Offsets is of type offest_t
-  // strings will ne null-terminated
-  // example: Tensor(['abc', 'de'], shape={2}, type=DE_STRING)
-  // |----------------------------------------------------------------|
-  // |             OFFSET ARRAY           |            STRINGS        |
-  // | bytes 0-3 | bytes 3-6 | bytes 7-10 | bytes 11-14 | bytes 15-17 |
-  // |     11    |    15     |     18     |     abc\0   |      de\0   |
-  // |----------------------------------------------------------------|
-  explicit Tensor(const std::vector<std::string> &strings,
-                  const TensorShape &shape = TensorShape::CreateUnknownRankShape());
-
-  // Same as Tensor(vector<string>) but the input is protobuf bytelist
-  explicit Tensor(const dataengine::BytesList &bytes_list,
-                  const TensorShape &shape = TensorShape::CreateUnknownRankShape());
-
-  // A static factory method to create the given flavour of derived Tensor
-  // Returns the base class reference for the Tensor.
-  // @param ptr output argument to hold the created Tensor of given tensor_impl
-  // @param tensor_impl - which implementation of Tensor
-  // @param shape - shape of the tensor
-  // @param type - datatype of the tensor
-  // @param data - data to be copied to Tensor new allocation
-  // @return Status Code
-  static Status CreateTensor(std::shared_ptr<Tensor> *, TensorImpl tensor_impl, const TensorShape &shape, DataType type,
-                             const unsigned char *data = nullptr);
-
-  // Create a copy of the input tensor
-  // @param out [out] output tensor to be generated
-  // @param in [in] orginal tensor to be copied
-  // @return Status
-  static Status CreateTensor(std::shared_ptr<Tensor> *out, const std::shared_ptr<Tensor> &in) {
-    const TensorAlloc *alloc = GlobalContext::Instance()->tensor_allocator();
-    *out = std::allocate_shared<Tensor>(*alloc, in->shape(), in->type(), in->GetBuffer(), in->SizeInBytes());
-    return Status::OK();
   }
 
 #ifdef ENABLE_PYTHON
-  // A static factory method to create a Tensor from a given py::array.
+  /// Create a Tensor from a given py::array
-  // @param ptr output argument to hold the created Tensor
+  /// \param[in] arr py::array
-  // @param arr py::array
+  /// \param[out] out Created tensor
-  // @return Status Code
+  /// \return Status Code
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, py::array arr);
+  static Status CreateFromNpArray(const py::array &arr, TensorPtr *out);
-
-  // Helper function to create a tensor from Numpy of strings
-  static Status CreateTensorFromNumpyString(std::shared_ptr<Tensor> *ptr, py::array arr);
 #endif
 
-  // A static factory method to create a Tensor from a given list of strings.
+  /// Create a tensor of type DE_STRING from a BytesList.
-  // @param ptr output argument to hold the created Tensor
+  /// \param[in] bytes_list protobuf's Bytelist
-  // @param strings elements of the tensor
+  /// \param[in] shape shape of the outout tensor
-  // @param shape shape of the tensor
+  /// \param[out] out created Tensor
-  // @return Status Code
+  /// \return Status Code
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const std::vector<std::string> &strings,
+  static Status CreateFromByteList(const dataengine::BytesList &bytes_list, const TensorShape &shape, TensorPtr *out);
-                             const TensorShape &shape = TensorShape::CreateUnknownRankShape());
 
-  // create tensor from protobuf bytelist with strings
+  /// Create a tensor of type UINT8 or INT8 from a BytesList.
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const dataengine::BytesList &bytes_list,
+  /// The tensor will be padded with ' ' to reach the required pad_size.
-                             const TensorShape &shape);
+  /// \param[in] bytes_list protobuf's Bytelist
+  /// \param[in] shape shape of the output tensor
+  /// \param[in] type type of created tensor. Should be DE_UINT8 or INT8
+  /// \param[in] pad_size The size of the tensor after padding
+  /// \param[out] out created Tensor
+  /// \return Status Code
+  static Status CreateFromByteList(const dataengine::BytesList &bytes_list, const TensorShape &shape,
+                                   const DataType &type, dsize_t pad_size, TensorPtr *out);
 
-  // A static factory method to create a Tensor from a given list of numbers.
+  /// Create a Tensor from a given list of values.
-  // @param ptr output argument to hold the created Tensor
+  /// \tparam type of the values to be inserted.
-  // @param items elements of the tensor
+  /// \param[in] items elements of the tensor
-  // @param shape shape of the tensor
+  /// \param[in] shape shape of the output tensor
-  // @return Status Code
+  /// \param[out] out output argument to hold the created Tensor
+  /// \return Status Code
   template <typename T>
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const std::vector<T> &items,
+  static Status CreateFromVector(const std::vector<T> &items, const TensorShape &shape, TensorPtr *out) {
-                             const TensorShape &shape_req = TensorShape::CreateUnknownRankShape()) {
+    CHECK_FAIL_RETURN_UNEXPECTED(
+      items.size() == shape.NumOfElements(),
+      "Number of elements in the vector does not match the number of elements of the shape required");
     DataType type = DataType::FromCType<T>();
+    // if items is empty, items_ptr would be nullptr. CreateFromMemory will handle this case.
     auto items_ptr = reinterpret_cast<const uchar *>(&items[0]);
-    TensorShape shape = shape_req;
+    return CreateFromMemory(shape, type, items_ptr, out);
-    if (!shape.known()) {
-      shape = TensorShape({static_cast<dsize_t>(items.size())});
-    }
-    return CreateTensor(ptr, TensorImpl::kFlexible, shape, type, items_ptr);
   }
 
-  // A static factory method to create a Tensor from a given number.
+  /// Create a 1D Tensor from a given list of values.
-  // @param ptr output argument to hold the created Tensor
+  /// \tparam type of the values to be inserted.
-  // @param item value
+  /// \param[in] items elements of the tensor
-  // @return Status Code
+  /// \param[out] out output argument to hold the created Tensor
+  /// \return Status Code
   template <typename T>
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const T &item) {
+  static Status CreateFromVector(const std::vector<T> &items, TensorPtr *out) {
-    return CreateTensor<T>(ptr, {item}, TensorShape::CreateScalar());
+    return CreateFromVector(items, TensorShape({static_cast<dsize_t>(items.size())}), out);
   }
 
-  // Create tensor from protobuf bytelist with uint8 or int8 types
+  /// Create a numeric scalar Tensor from the given value.
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const dataengine::BytesList &bytes_list,
+  /// \tparam T type of value
-                             const TensorShape &shape, const DataType &type, dsize_t pad_size);
+  /// \param[in] item value
+  /// \param[out] out Created tensor
+  /// \return Status code
+  template <typename T>
+  static Status CreateScalar(const T &item, TensorPtr *out) {
+    DataType type = DataType::FromCType<T>();
+    auto item_ptr = reinterpret_cast<const uchar *>(&item);
+    return CreateFromMemory(TensorShape::CreateScalar(), type, item_ptr, out);
+  }
 
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const std::string &path);
+  /// Create a tensor from a binary file on disk.
+  /// \param[in] path file to be read
+  /// \param[out] out Created Tensor
+  /// \return Status code
+  static Status CreateFromFile(const std::string &path, TensorPtr *out);
 
-  // Copy raw data of a array based on shape and strides to the destination pointer
+  /// Destruct the tensor and release the memory using the allocator
-  // @param dst Pointer to the destination array where the content is to be copied
-  // @param src Pointer to the source of strided array to be copied
-  // @param shape - shape of the source array
-  // @param strides - strides of the source array
-  // @param type_size - number of bytes needed to store one array element's type
-  // @return Status Code
-  static Status CopyStridedArray(unsigned char *dst, unsigned char *src, std::vector<dsize_t> shape,
-                                 std::vector<dsize_t> strides, uint8_t type_size);
-
-  // Release the memory using the allocator
   virtual ~Tensor();
 
-  // compare the tensor shape and data
+  /// Equality operator. compares tensor shape, type and data
+  /// \param[in] rhs Tensor to be compared with
+  /// \return bool
   bool operator==(const Tensor &rhs) const;
 
   bool operator!=(const Tensor &rhs) const { return !((*this) == rhs); }
 
-  // Get item located at `index`, caller needs to provide the type.
+  /// Get item located at `index`, caller needs to provide the type.
-  // @tparam T
+  /// \tparam T
-  // @param index vector<dsize_t>
+  /// \param[in] index vector<dsize_t>
-  // @return return the item specified at index
+  /// \return return the item specified at index
   template <typename T>
   Status GetItemAt(T *o, const std::vector<dsize_t> &index) const;
 
-  // Get string located at `index`.
+  /// Get string located at `index`.
-  // @param index vector<dsize_t>
+  /// \param[in] index vector<dsize_t>
-  // @return return std::string_view specified at index
+  /// \return return std::string_view specified at index
   Status GetItemAt(std::string_view *o, const std::vector<dsize_t> &index) const;
 
   template <typename T>
@@ -225,22 +211,21 @@ class Tensor {
   template <typename T>
   Status GetFloatAt(T *o, const std::vector<dsize_t> &index) const;
 
-  // set item at location specified by index
+  /// set item at location specified by index
-  // @tparam `T`
+  /// \tparam `T`
-  // @param index
+  /// \param[in] index
-  // @param value of type `T`
+  /// \param[in] value of type `T`
   template <typename T>
   Status SetItemAt(const std::vector<dsize_t> &index, const T &value) {
-    RETURN_IF_NOT_OK(AllocateBuffer(SizeInBytes()));
     T *ptr = nullptr;
     RETURN_IF_NOT_OK(GetItemPtr<T>(&ptr, index));
     *ptr = value;
     return Status::OK();
   }
 
-  // set string item at location specified by index
+  /// set string item at location specified by index
-  // @param index
+  /// \param[in] index
-  // @param value of type std::string
+  /// \param[in] value of type std::string
   Status SetItemAt(const std::vector<dsize_t> &index, const std::string &value) {
     RETURN_UNEXPECTED_IF_NULL(data_);
     uchar *ptr = nullptr;
@@ -253,7 +238,8 @@ class Tensor {
 
     return Status::OK();
   }
-  // fill tensor with Zeros. Does not support strings.
+
+  /// fill tensor with Zeros. Does not support strings.
   Status Zero() {
     CHECK_FAIL_RETURN_UNEXPECTED(type_ != DataType::DE_STRING, "Cannot use Zero on tensor of strings..");
     dsize_t size = SizeInBytes();
@@ -262,13 +248,12 @@ class Tensor {
     return Status::OK();
   }
 
-  // Fill all elements in the Tensor with the given value of type `T`.  Does not support strings.
+  /// Fill all elements in the Tensor with the given value of type `T`.  Does not support strings.
-  // @tparam T
+  /// \tparam T
-  // @param value
+  /// \param value[in]
   template <typename T>
   Status Fill(const T &value) {
     CHECK_FAIL_RETURN_UNEXPECTED(type_ != DataType::DE_STRING, "Cannot use fill on tensor of strings.");
-    RETURN_IF_NOT_OK(AllocateBuffer(SizeInBytes()));
     int64_t cellSize = type_.SizeInBytes();
     if ((data_ != nullptr) && type_.IsCompatible<T>()) {
       for (dsize_t i = 0; i < Size(); i++) {
@@ -283,91 +268,86 @@ class Tensor {
     }
   }
 
-  // Getter function for shape
+  /// Getter function for shape
-  // @return
+  /// \return
   const TensorShape &shape() const { return shape_; }
 
   /// Check if tensor has data
   /// \return bool - true if tensor is empty
-  bool HasData() const;
+  bool HasData() const { return data_ != nullptr; }
 
-  // Reshape the tensor. The given shape should have the same number of elements in the Tensor
+  /// Reshape the tensor. The given shape should have the same number of elements in the Tensor
-  // @param shape
+  /// \param shape
   virtual Status Reshape(const TensorShape &shape);
 
-  // @return number of elements in this tensor
+  /// \return number of elements in this tensor
   dsize_t Size() const { return shape().NumOfElements(); }
 
-  // @return the number of bytes this tensor is needs
+  /// \return the number of bytes this tensor is needs
   dsize_t SizeInBytes() const {
     if (data_end_ == nullptr) return type_.SizeInBytes() * shape_.NumOfElements();
     return data_end_ - data_;
   }
 
-  // @return the rank of the tensor
+  /// \return the rank of the tensor
   dsize_t Rank() const { return shape().Rank(); }
 
-  // Get the starting memory address as a constant for the data of the tensor.  This potentially
+  /// Get the starting memory address as a constant for the data of the tensor.  This potentially
-  // drives an allocation if the data area.
+  /// drives an allocation if the data area.
-  // @return const unsigned char*
+  /// \return const unsigned char*
-  const unsigned char *GetBuffer() const;
+  const unsigned char *GetBuffer() const { return data_; }
 
-  // Skip the offsets and returns the start of the buffer where the real strings is stored. Caller needs to check if the
+  /// Getter of the type
-  // tensor's type is a string, otherwise undefined address would be returned.
+  /// \return
-  // @return address of the first string of the tensor.
-  uchar *GetStringsBuffer() const { return data_ + kOffsetSize * shape_.NumOfElements() + kOffsetSize; }
-
-  // Getter of the type
-  // @return
   DataType type() const { return type_; }
 
-  // Provide stream operator for displaying it
+  /// Provide stream operator for displaying it
-  // @param output stream
+  /// \param output stream
-  // @param so the Tensor object to be printed
+  /// \param so the Tensor object to be printed
-  // @return output stream
+  /// \return output stream
   friend std::ostream &operator<<(std::ostream &out, const Tensor &so) {
     so.Print(out);
     return out;
   }
 
-  // Invalidate this Tensor by setting the type and shape to unknown and MData to null.
+  /// Invalidate this Tensor by setting the type and shape to unknown and MData to null.
-  // Calling this method will make the Tensor and its data inaccessible, use it with caution.
+  /// Calling this method will make the Tensor and its data inaccessible, use it with caution.
   void Invalidate();
 
-  // Copy input tensor into self at the location index.
+  /// Copy input tensor into self at the location index.
-  // Index is a vector of axises which can be incomplete:
+  /// Index is a vector of axises which can be incomplete:
-  // Ex: shape <2,3>, inserting into index {0} will replace the first row. index {1,2} will replace the last cell.
+  /// Ex: shape <2,3>, inserting into index {0} will replace the first row. index {1,2} will replace the last cell.
-  // @param index
+  /// \param index
-  // @param input
+  /// \param input
-  // @return Status code
+  /// \return Status code
   Status InsertTensor(const std::vector<dsize_t> &index, const std::shared_ptr<Tensor> &input);
 
-  // Find the address of the given index. Used in InsertTensor.
+  /// Find the address of the given index. Used in InsertTensor.
-  // Example:
+  /// Example:
-  //      Tensor t= [[1,2],[3,4]] , StartAddrOfIndex({0}) -> &1
+  ///      Tensor t= [[1,2],[3,4]] , StartAddrOfIndex({0}) -> &1
-  // @param index  incomplete index
+  /// \param index  incomplete index
-  // @param output: startAddrofIndex
+  /// \param output: startAddrofIndex
-  // @param output: remaining
+  /// \param output: remaining
-  // @return Status code
+  /// \return Status code
   Status StartAddrOfIndex(std::vector<dsize_t> ind, uchar **start_addr_of_index, TensorShape *remaining);
 
-  // Expand the shape of the Tensor with one extra dimension.
+  /// Expand the shape of the Tensor with one extra dimension.
-  // For example, if the shape is <512,512,3>:
+  /// For example, if the shape is <512,512,3>:
-  //     *- ExpandDim(0) gives: <1,512,512,3>
+  ///     *- ExpandDim(0) gives: <1,512,512,3>
-  //     *- ExpandDim(1) gives: <512,1,512,3>
+  ///     *- ExpandDim(1) gives: <512,1,512,3>
-  //     *- ExpandDim(3) gives: <512,512,3,1>
+  ///     *- ExpandDim(3) gives: <512,512,3,1>
-  // @param axis location of the dim
+  /// \param axis location of the dim
   virtual Status ExpandDim(const dsize_t &axis);
 
   virtual void Squeeze();
 
-  // Calculates the strides of the Tensor
+  /// Calculates the strides of the Tensor
-  // Ex: Tensor of shape <4,2,2> and type DE_UINT8 (1 byte)
+  /// Ex: Tensor of shape <4,2,2> and type DE_UINT8 (1 byte)
-  // The strides will be {6,2,1}.
+  /// The strides will be {6,2,1}.
-  // Ex: Tensor of shape <4,2,2> and type DE_UINT32 (4 byte)
+  /// Ex: Tensor of shape <4,2,2> and type DE_UINT32 (4 byte)
-  // The strides will be {24,8,4}.
+  /// The strides will be {24,8,4}.
-  // @return vector of integers
+  /// \return vector of integers
-  std::vector<dsize_t> Strides();
+  std::vector<dsize_t> Strides() const;
 
   std::string ToString() {
     std::stringstream ss;
@@ -375,26 +355,26 @@ class Tensor {
     return ss.str();
   }
 
-  // Handle negative indices.
+  /// Handle negative indices.
   static inline dsize_t HandleNeg(dsize_t index, dsize_t length) { return (index < 0) ? (index + length) : index; }
 
-  // Slice tensor bases on the given indicies. Copy the sliced data into out tensor. Only rank1 tensors are supported.
+  /// Slice tensor bases on the given indicies. Copy the sliced data into out tensor. Only rank1 tensors are supported.
-  // Based on the type of tensor, SliceNumeric or SliceString will be called
+  /// Based on the type of tensor, SliceNumeric or SliceString will be called
-  // @param out Tensor
+  /// \param[out] out Tensor
-  // @param indices vector of indices
+  /// \param[in] indices vector of indices
-  // @return Status error code
+  /// \return Status error code
-  Status Slice(std::shared_ptr<Tensor> *out, const std::vector<dsize_t> &indices);
+  Status Slice(TensorPtr *out, const std::vector<dsize_t> &indices);
 
-  // Slice numeric tensors.
+  /// Slice numeric tensors.
-  Status SliceNumeric(std::shared_ptr<Tensor> *out, const std::vector<dsize_t> &indices);
+  Status SliceNumeric(TensorPtr *out, const std::vector<dsize_t> &indices);
 
-  // Slice string tensors
+  /// Slice string tensors
-  Status SliceString(std::shared_ptr<Tensor> *out, const std::vector<dsize_t> &indices);
+  Status SliceString(TensorPtr *out, const std::vector<dsize_t> &indices);
 
 #ifdef ENABLE_PYTHON
-  // Constructs numpy array from input tensor
+  /// Constructs numpy array from input tensor
-  // @param data this data is the location of python data
+  /// \param[in] data this data is the location of python data
-  // @return Status code
+  /// \return Status code
   Status GetDataAsNumpy(py::array *data);
 
   Status GetDataAsNumpyStrings(py::array *data);
@@ -402,12 +382,12 @@ class Tensor {
   static Status GetBufferInfo(Tensor *t, py::buffer_info *out);
 #endif
 
-  // Concatenate based on given tensor, can fill in current tensor with a smaller one, unlike InsertTensor
+  /// Concatenate based on given tensor, can fill in current tensor with a smaller one, unlike InsertTensor
   Status Concatenate(const std::vector<dsize_t> &index, const std::shared_ptr<Tensor> &input);
 
-  // TensorIterator is a linear iterator that can be used to iterate over the elements of the Tensor
+  /// TensorIterator is a linear iterator that can be used to iterate over the elements of the Tensor
-  // The order  elements  is as the memory layout (i.e., row-major) [[1,2,3],[4,5,6] --> 1,2,3,4,5,6
+  /// The order  elements  is as the memory layout (i.e., row-major) [[1,2,3],[4,5,6] --> 1,2,3,4,5,6
-  // @tparam T type of values in the Tensor Iterator
+  /// \tparam T type of values in the Tensor Iterator
   template <typename T, bool = true>
   class TensorIterator {
    public:
@@ -498,7 +478,7 @@ class Tensor {
   };
 
   // Specialization of TensorIterator for strings. It returns std::string_view for every item.
-  // @tparam DUMMY, used to mbe able to specialize the inner class
+  // \tparam DUMMY, used to mbe able to specialize the inner class
   template <bool DUMMY>
   class TensorIterator<std::string_view, DUMMY> {
    public:
@@ -585,84 +565,192 @@ class Tensor {
     const char *data_;
   };
 
-  // Return a TensorIterator that points to the start of the Tensor.
+  /// Return a TensorIterator that points to the start of the Tensor.
-  // It's the user responsibility to use the correct type that matches the Tensor type
+  /// It's the user responsibility to use the correct type that matches the Tensor type
-  // @param T The type of values in the Tensor
+  /// \tparam T The type of values in the Tensor
-  // @return TensorIterator
+  /// \return TensorIterator
   template <typename T>
   TensorIterator<T> begin() {
-    AllocateBuffer(SizeInBytes());
     return TensorIterator<T>(data_);
   }
 
-  // Return a linear iterator that points to the place after the last element of the Tensor.
+  /// Return a linear iterator that points to the place after the last element of the Tensor.
-  // @tparam T The type of values in the Tensor
+  /// \tparam T The type of values in the Tensor
-  // @return TensorIterator
+  /// \return TensorIterator
   template <typename T>
   TensorIterator<T> end() {
     return TensorIterator<T>(data_end_);
   }
 
-  // Copies the last dimension at `index` from Tensor `src` to this Tensor.
+  /// Copies the last dimension at `index` from Tensor `src` to this Tensor.
-  // @param src Tensor
+  /// \param[in] src Tensor
-  // @param index vector to the start of the dimension. The last dim should be 0
+  /// \param[in] index vector to the start of the dimension. The last dim should be 0
-  // @return Status
+  /// \return Status
   Status CopyLastDimAt(const std::shared_ptr<Tensor> &src, const std::vector<dsize_t> &index);
 
  protected:
-  // Get the starting memory address for the data of the tensor.  This potentially
+  /// Allocate memory for the tensor using the data_allocator
-  // drives an allocation if the data is null.
+  /// \param[in] length number of bytes to be allocated
-  // @return unsigned char*
+  /// \return Error Status
-  unsigned char *GetMutableBuffer();
+  Status AllocateBuffer(const dsize_t &length);
 
-  // A function that prints Tensor recursively, first called by print
+  /// Get the starting memory address for the data of the tensor.  This potentially
-  // @param out
+  /// drives an allocation if the data is null.
-  // @param cur_dim
+  /// \return unsigned char*
-  // @param cur_index
+  unsigned char *GetMutableBuffer() { return data_; }
+
+  /// A function that prints Tensor recursively, first called by print
+  /// \param[in] out
+  /// \param[in] cur_dim
+  /// \param[in] cur_index
   void PrintRecursive(std::ostream &out, int32_t cur_dim, const std::vector<dsize_t> &cur_index) const;
 
-  // A function that prints info about the tensor
+  /// A function that prints info about the tensor
-  // @param out output stream
+  /// \param[out] out output stream
   void Print(std::ostream &out) const;
 
-  // A function that print the value as specified by its index
+  /// A function that print the value as specified by its index
-  // @param index vector representing the index
+  /// \param[in] index vector representing the index
-  // @param out
+  /// \param[out] out
   void PrintItemAt(const std::vector<dsize_t> &index, std::ostream &out) const;
 
-  // Get pointer to item located at `index`, caller needs to provide the type.
+  /// Get pointer to item located at `index`, caller needs to provide the type.
-  // @tparam T
+  /// \tparam T
-  // @param index vector<dsize_t>
+  /// \param[in] index vector<dsize_t>
-  // @return return a pointer to the item specified at index of type `T`
+  /// \return return a pointer to the item specified at index of type `T`
   template <typename T>
   Status GetItemPtr(T **, const std::vector<dsize_t> &index) const;
 
-  // Get pointer to string located at `index` and the length of string
+  /// Get pointer to string located at `index` and the length of string
-  // @param index vector<dsize_t>
+  /// \param[in] index vector<dsize_t>
-  // @return return a pointer to the string specified at index and the length of the string
+  /// \return return a pointer to the string specified at index and the length of the string
   Status GetItemPtr(uchar **, const std::vector<dsize_t> &index, offset_t *length = nullptr) const;
 
-  // Given a flat index of an item string, return the start and length of the item
+  /// Given a flat index of an item string, return the start and length of the item
-  // @param index flat index of the item
+  /// \param[in] index flat index of the item
-  // @return start address of the ths string
+  /// \param[out] start address of the ths string
-  // @return length of the string
+  /// \param[out] length of the string
   Status GetStringAt(dsize_t index, uchar **string_start, offset_t *length) const;
 
-  // all access to shape_ should be via shape
+  /// Skip the offsets and returns the start of the buffer where the real strings is stored. Caller needs to check if
+  /// the tensor's type is a string, otherwise undefined address would be returned. \return address of the first string
+  /// of the tensor.
+  uchar *GetStringsBuffer() const { return data_ + kOffsetSize * shape_.NumOfElements() + kOffsetSize; }
+
+  /// all access to shape_ should be via shape
   TensorShape shape_;
-  // data type of tensor
+  /// data type of tensor
   DataType type_;
-  // pointer to the start of the physical data
+  /// pointer to the start of the physical data
   unsigned char *data_;
-  // An allocator for data_
+  /// An allocator for data_
   CharAllocPtr data_allocator_;
-  // pointer to the end of the physical data
+  /// pointer to the end of the physical data
   unsigned char *data_end_ = nullptr;
+
+ private:
+  /// Helper function to create a tensor from Numpy array of strings
+  /// \param[in] arr Numpy array
+  /// \param[out] out Created Tensor
+  /// \return Status
+  static Status CreateFromNpString(py::array arr, TensorPtr *out);
+
+  /// Copy raw data of a array based on shape and strides to the destination pointer
+  /// \param dst [out] Pointer to the destination array where the content is to be copied
+  /// \param[in] src Pointer to the source of strided array to be copied
+  /// \param[in] shape shape of the source array
+  /// \param[in] strides strides of the source array
+  /// \param[in] type_size number of bytes needed to store one array element's type
+  /// \return Status Code
+  static Status CopyStridedArray(unsigned char *dst, unsigned char *src, std::vector<dsize_t> shape,
+                                 std::vector<dsize_t> strides, uint8_t type_size);
+
+  /// const of the size of the offset variable
+  static constexpr uint8_t kOffsetSize = sizeof(offset_t);
 };
 template <>
 inline Tensor::TensorIterator<std::string_view> Tensor::end<std::string_view>() {
   return TensorIterator<std::string_view>(data_, shape_.NumOfElements());
 }
+
+/// Create a Tensor from a given list of strings.
+/// @note: The memory layout of a Tensor of strings consists of the Offset_array followed by the strings.
+/// The offset array will store one extra value to find the length of the last string.
+/// OFFSET_1, OFFSET_2, ..., OFFSET_n+1, STRING_1, STRING_2, ..., STRING_n
+/// The value of each offset is the start index of the corresponding string
+/// Offsets is of type offset_t
+/// strings will ne null-terminated
+/// example: Tensor(['abc', 'de'], shape={2}, type=DE_STRING)
+/// |----------------------------------------------------------------|
+/// |             OFFSET ARRAY           |            STRINGS        |
+/// | bytes 0-3 | bytes 3-6 | bytes 7-10 | bytes 11-14 | bytes 15-17 |
+/// |     11    |    15     |     18     |     abc\0   |      de\0   |
+/// |----------------------------------------------------------------|
+/// \param[in] items elements of the tensor
+/// \param[in] shape shape of the output tensor
+/// \param[out] out output argument to hold the created Tensor
+/// \return Status Code
+template <>
+inline Status Tensor::CreateFromVector<std::string>(const std::vector<std::string> &items, const TensorShape &shape,
+                                                    TensorPtr *out) {
+  CHECK_FAIL_RETURN_UNEXPECTED(
+    items.size() == shape.NumOfElements(),
+    "Number of elements in the vector does not match the number of elements of the shape required");
+  const TensorAlloc *alloc = GlobalContext::Instance()->tensor_allocator();
+  *out = std::allocate_shared<Tensor>(*alloc, TensorShape({static_cast<dsize_t>(items.size())}),
+                                      DataType(DataType::DE_STRING));
+  if (items.size() == 0) {
+    if (shape.known()) {
+      return (*out)->Reshape(shape);
+    }
+  }
+  auto length_sum = [](dsize_t sum, const std::string &s) { return s.length() + sum; };
+  dsize_t total_length = std::accumulate(items.begin(), items.end(), 0, length_sum);
+
+  // total bytes needed = offset array + strings
+  // offset array needs to store one offset var per element + 1 extra to get the length of the last string.
+  // strings will be null-terminated --> need 1 extra byte per element
+  dsize_t num_bytes = (kOffsetSize + 1) * (*out)->shape_.NumOfElements() + kOffsetSize + total_length;
+
+  (*out)->AllocateBuffer(num_bytes);
+  auto offset_arr = reinterpret_cast<offset_t *>((*out)->data_);
+  uchar *buf = (*out)->GetStringsBuffer();
+
+  offset_t offset = buf - (*out)->data_;  // the first string will start here
+  uint32_t i = 0;
+  for (const auto &str : items) {
+    //  insert the start index of the string.
+    offset_arr[i++] = offset;
+    // total bytes are reduced by kOffsetSize
+    num_bytes -= kOffsetSize;
+    // insert actual string
+    int ret_code = memcpy_s((*out)->data_ + offset, num_bytes, common::SafeCStr(str), str.length() + 1);
+    if (ret_code != 0) MS_LOG(ERROR) << "Cannot copy string into Tensor";
+    //  next string will be stored right after the current one.
+    offset = offset + str.length() + 1;
+    // total bytes are reduced by the length of the string
+    num_bytes -= str.length() + 1;
+  }
+  // store one more offset value so we can get the length of the last string
+  // length[last_element] = offset_arr[last_element + 1] - offset_arr[last_element]
+  offset_arr[i] = offset;
+
+  (*out)->data_end_ = (*out)->data_ + offset_arr[i];
+
+  MS_ASSERT(num_bytes == 0);
+  if (shape.known()) {
+    RETURN_IF_NOT_OK((*out)->Reshape(shape));
+  }
+  return Status::OK();
+}
+/// Create a string scalar Tensor from the given value.
+/// \param[in] item value
+/// \param[out] out Created tensor
+/// \return Status code
+template <>
+inline Status Tensor::CreateScalar<std::string>(const std::string &item, TensorPtr *out) {
+  return CreateFromVector<std::string>({item}, TensorShape::CreateScalar(), out);
+}
 }  // namespace dataset
 }  // namespace mindspore
 #endif  // MINDSPORE_CCSRC_MINDDATA_DATASET_CORE_TENSOR_H_

mindspore/ccsrc/minddata/dataset/engine/cache/cache_request.cc

@@ -141,8 +141,9 @@ Status BatchFetchRequest::RestoreOneTensor(const TensorMetaMsg *col_ts, const Re
 #undef CASE
 
   DataType type(dest);
-  std::shared_ptr<Tensor> ts =
+  std::shared_ptr<Tensor> ts;
-    std::make_shared<Tensor>(shape, type, static_cast<const unsigned char *>(data.GetPointer()), data.GetSize());
+  RETURN_IF_NOT_OK(
+    Tensor::CreateFromMemory(shape, type, static_cast<const unsigned char *>(data.GetPointer()), data.GetSize(), &ts));
   // Next we restore the real data which can be embedded or stored separately.
   if (ts->SizeInBytes() != data.GetSize()) {
     MS_LOG(ERROR) << "Unexpected length. Read " << data.GetSize() << ". Expected " << ts->SizeInBytes() << ".\n"

mindspore/ccsrc/minddata/dataset/engine/datasetops/batch_op.cc

@@ -176,12 +176,15 @@ Status BatchOp::BatchRows(const std::unique_ptr<TensorQTable> *src, const std::u
 
     std::shared_ptr<Tensor> new_tensor;
     if (first_type.IsNumeric()) {  // numeric tensor
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(&new_tensor, TensorImpl::kFlexible, new_shape, first_type));
+      RETURN_IF_NOT_OK(Tensor::CreateEmpty(new_shape, first_type, &new_tensor));
       dsize_t j = 0;
       for (auto row : **src) {
         std::shared_ptr<Tensor> old_tensor = row.at(i);  // row j, column i
         if (old_tensor->shape() == first_shape) {        // check the newly popped rows have the same dim as the first
-          RETURN_IF_NOT_OK(new_tensor->InsertTensor({j++}, old_tensor));
+          if (new_shape.NumOfElements() != 0) {
+            RETURN_IF_NOT_OK(new_tensor->InsertTensor({j++}, old_tensor));
+          }
+          // Don't do anything if the tensor has no data
         } else {
           RETURN_STATUS_UNEXPECTED("[Batch ERROR] Inconsistent TensorShapes of Column " + std::to_string(i));
         }
@@ -194,7 +197,7 @@ Status BatchOp::BatchRows(const std::unique_ptr<TensorQTable> *src, const std::u
           strings.emplace_back(*itr);
         }
       }
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(&new_tensor, strings, new_shape));
+      RETURN_IF_NOT_OK(Tensor::CreateFromVector(strings, new_shape, &new_tensor));
     }
     batched_row.emplace_back(new_tensor);
   }
@@ -352,7 +355,7 @@ Status BatchOp::InvokeBatchMapFunc(TensorBatchTable *input, TensorBatchTable *ou
         py::list output_list = py::cast<py::list>(ret_tuple[i]);
         for (size_t j = 0; j < output_list.size(); j++) {
           std::shared_ptr<Tensor> out;
-          RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, py::cast<py::array>(output_list[j])));
+          RETURN_IF_NOT_OK(Tensor::CreateFromNpArray(py::cast<py::array>(output_list[j]), &out));
           output_batch.push_back(std::move(out));
         }
         output->push_back(std::move(output_batch));

mindspore/ccsrc/minddata/dataset/engine/datasetops/cache_merge_op.cc

@@ -226,7 +226,8 @@ void CacheMergeOp::TensorRowRequest::WakeUpAny(TensorRow &&row) {
   if (GetState() == State::kEmpty) {
     // We will do a deep copy
     for (auto &ts : row) {
-      auto out_ts = std::make_shared<Tensor>(ts->shape(), ts->type(), ts->GetBuffer(), ts->SizeInBytes());
+      std::shared_ptr<Tensor> out_ts;
+      Tensor::CreateFromTensor(ts, &out_ts);
       cleaner_copy_.push_back(out_ts);
     }
     cleaner_copy_.setId(row.getId());

mindspore/ccsrc/minddata/dataset/engine/datasetops/device_queue_op.cc

@@ -72,6 +72,7 @@ Status DeviceQueueOp::CheckExceptions(const std::unique_ptr<DataBuffer> &buffer)
     buffer->GetRow(0, &row);
     for (const auto &item : row) {
       CHECK_FAIL_RETURN_UNEXPECTED(item->type().IsNumeric(), "Cannot send tensor of string type to device.");
+      CHECK_FAIL_RETURN_UNEXPECTED(item->HasData(), "Cannot send tensor with no data.");
     }
   }
   return Status::OK();

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/celeba_op.cc

@@ -359,7 +359,7 @@ Status CelebAOp::LoadTensorRow(row_id_type row_id, const std::pair<std::string,
 
   Path path(folder_path_);
   Path image_path = path / image_label.first;
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&image, image_path.toString()));
+  RETURN_IF_NOT_OK(Tensor::CreateFromFile(image_path.toString(), &image));
   if (decode_ == true) {
     Status rc = Decode(image, &image);
     if (rc.IsError()) {
@@ -369,9 +369,8 @@ Status CelebAOp::LoadTensorRow(row_id_type row_id, const std::pair<std::string,
     }
   }
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&label, data_schema_->column(1).tensorImpl(),
+  RETURN_IF_NOT_OK(
-                                        TensorShape({1, (uint32_t)image_label.second.size()}),
+    Tensor::CreateEmpty(TensorShape({1, (uint32_t)image_label.second.size()}), data_schema_->column(1).type(), &label));
-                                        data_schema_->column(1).type()));
   RETURN_IF_NOT_OK(label->Zero());
   for (uint32_t index = 0; index < image_label.second.size(); index++) {
     if (image_label.second[index] == 1) {

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/cifar_op.cc

@@ -190,15 +190,12 @@ Status CifarOp::LoadTensorRow(uint64_t index, TensorRow *trow) {
   std::shared_ptr<Tensor> label;
   std::shared_ptr<Tensor> fine_label;
   std::shared_ptr<Tensor> ori_image = cifar_image_label_pairs_[index].first;
-  std::shared_ptr<Tensor> copy_image =
+  std::shared_ptr<Tensor> copy_image;
-    std::make_shared<Tensor>(ori_image->shape(), ori_image->type(), ori_image->GetBuffer());
+  RETURN_IF_NOT_OK(Tensor::CreateFromTensor(ori_image, &copy_image));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&label, data_schema_->column(1).tensorImpl(), data_schema_->column(1).shape(),
+  RETURN_IF_NOT_OK(Tensor::CreateScalar(cifar_image_label_pairs_[index].second[0], &label));
-                                        data_schema_->column(1).type(),
+
-                                        reinterpret_cast<unsigned char *>(&cifar_image_label_pairs_[index].second[0])));
   if (cifar_image_label_pairs_[index].second.size() > 1) {
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(
+    RETURN_IF_NOT_OK(Tensor::CreateScalar(cifar_image_label_pairs_[index].second[1], &fine_label));
-      &fine_label, data_schema_->column(2).tensorImpl(), data_schema_->column(2).shape(),
-      data_schema_->column(2).type(), reinterpret_cast<unsigned char *>(&cifar_image_label_pairs_[index].second[1])));
     (*trow) = TensorRow(index, {copy_image, std::move(label), std::move(fine_label)});
   } else {
     (*trow) = TensorRow(index, {copy_image, std::move(label)});
@@ -359,9 +356,8 @@ Status CifarOp::ParseCifarData() {
       }
 
       std::shared_ptr<Tensor> image_tensor;
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(&image_tensor, data_schema_->column(0).tensorImpl(),
+      RETURN_IF_NOT_OK(Tensor::CreateEmpty(TensorShape({kCifarImageHeight, kCifarImageWidth, kCifarImageChannel}),
-                                            TensorShape({kCifarImageHeight, kCifarImageWidth, kCifarImageChannel}),
+                                           data_schema_->column(0).type(), &image_tensor));
-                                            data_schema_->column(0).type()));
       auto itr = image_tensor->begin<uint8_t>();
       uint32_t total_pix = kCifarImageHeight * kCifarImageWidth;
       for (int pix = 0; pix < total_pix; ++pix) {

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/clue_op.cc

@@ -127,7 +127,7 @@ Status ClueOp::LoadTensor(const std::string &line, std::unique_ptr<TensorQTable>
   (*tensor_table)->push_back(std::move(tRow));
 
   std::shared_ptr<Tensor> tensor;
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&tensor, {line}, TensorShape::CreateScalar()));
+  RETURN_IF_NOT_OK(Tensor::CreateScalar(line, &tensor));
   (**tensor_table)[row][0] = std::move(tensor);
   return Status::OK();
 }
@@ -144,26 +144,19 @@ Status ClueOp::GetValue(const nlohmann::json &js, std::vector<std::string> key_c
   std::string final_str = key_chain.back();
   switch (cursor.type()) {
     case nlohmann::detail::value_t::string:
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(t, {cursor.get<std::string>()}, TensorShape::CreateScalar()));
+      RETURN_IF_NOT_OK(Tensor::CreateScalar(cursor.get<std::string>(), t));
       break;
-
     case nlohmann::detail::value_t::number_integer:
-      RETURN_IF_NOT_OK(
+      RETURN_IF_NOT_OK(Tensor::CreateScalar(cursor.get<int32_t>(), t));
-        Tensor::CreateTensor(t, TensorImpl::kFlexible, TensorShape::CreateScalar(), DataType(DataType::DE_INT32)));
-      (*t)->SetItemAt<int32_t>({0}, cursor.get<int32_t>());
       break;
     case nlohmann::detail::value_t::number_unsigned:
-      RETURN_IF_NOT_OK(
+      RETURN_IF_NOT_OK(Tensor::CreateScalar(cursor.get<uint32_t>(), t));
-        Tensor::CreateTensor(t, TensorImpl::kFlexible, TensorShape::CreateScalar(), DataType(DataType::DE_INT32)));
-      (*t)->SetItemAt<int32_t>({0}, cursor.get<uint32_t>());
       break;
     case nlohmann::detail::value_t::number_float:
-      RETURN_IF_NOT_OK(
+      RETURN_IF_NOT_OK(Tensor::CreateScalar(cursor.get<float>(), t));
-        Tensor::CreateTensor(t, TensorImpl::kFlexible, TensorShape::CreateScalar(), DataType(DataType::DE_FLOAT32)));
-      (*t)->SetItemAt<int32_t>({0}, cursor.get<float>());
       break;
     case nlohmann::detail::value_t::array:
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(t, {cursor.get<std::vector<std::string>>()}, TensorShape::CreateScalar()));
+      RETURN_IF_NOT_OK(Tensor::CreateFromVector(cursor.get<std::vector<std::string>>(), t));
       break;
     default:
       break;

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/coco_op.cc

@@ -239,9 +239,8 @@ Status CocoOp::LoadTensorRow(row_id_type row_id, const std::string &image_id, Te
   }
 
   std::vector<dsize_t> bbox_dim = {bbox_row_num, bbox_column_num};
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&coordinate, data_schema_->column(1).tensorImpl(), TensorShape(bbox_dim),
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(bbox_row, TensorShape(bbox_dim), &coordinate));
-                                        data_schema_->column(1).type(),
+
-                                        reinterpret_cast<unsigned char *>(&bbox_row[0])));
   if (task_type_ == TaskType::Detection) {
     RETURN_IF_NOT_OK(LoadDetectionTensorRow(row_id, image_id, image, coordinate, trow));
   } else if (task_type_ == TaskType::Stuff || task_type_ == TaskType::Keypoint) {
@@ -278,13 +277,12 @@ Status CocoOp::LoadDetectionTensorRow(row_id_type row_id, const std::string &ima
       iscrowd_row.push_back(annotation[i]);
     }
   }
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(
-    &category_id, data_schema_->column(2).tensorImpl(), TensorShape({static_cast<dsize_t>(category_id_row.size()), 1}),
+    category_id_row, TensorShape({static_cast<dsize_t>(category_id_row.size()), 1}), &category_id));
-    data_schema_->column(2).type(), reinterpret_cast<unsigned char *>(&category_id_row[0])));
+
+  RETURN_IF_NOT_OK(
+    Tensor::CreateFromVector(iscrowd_row, TensorShape({static_cast<dsize_t>(iscrowd_row.size()), 1}), &iscrowd));
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(
-    &iscrowd, data_schema_->column(3).tensorImpl(), TensorShape({static_cast<dsize_t>(iscrowd_row.size()), 1}),
-    data_schema_->column(3).type(), reinterpret_cast<unsigned char *>(&iscrowd_row[0])));
   (*trow) = TensorRow(row_id, {std::move(image), std::move(coordinate), std::move(category_id), std::move(iscrowd)});
   return Status::OK();
 }
@@ -302,9 +300,8 @@ Status CocoOp::LoadSimpleTensorRow(row_id_type row_id, const std::string &image_
 
   item_queue = itr_item->second;
   std::vector<dsize_t> bbox_dim = {static_cast<dsize_t>(item_queue.size()), 1};
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&item, data_schema_->column(2).tensorImpl(), TensorShape(bbox_dim),
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(item_queue, TensorShape(bbox_dim), &item));
-                                        data_schema_->column(2).type(),
+
-                                        reinterpret_cast<unsigned char *>(&item_queue[0])));
   (*trow) = TensorRow(row_id, {std::move(image), std::move(coordinate), std::move(item)});
   return Status::OK();
 }
@@ -334,18 +331,14 @@ Status CocoOp::LoadMixTensorRow(row_id_type row_id, const std::string &image_id,
       area_row.push_back(annotation[i]);
     }
   }
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(
+    category_id_row, TensorShape({static_cast<dsize_t>(category_id_row.size()), 1}), &category_id));
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(
+  RETURN_IF_NOT_OK(
-    &category_id, data_schema_->column(2).tensorImpl(), TensorShape({static_cast<dsize_t>(category_id_row.size()), 1}),
+    Tensor::CreateFromVector(iscrowd_row, TensorShape({static_cast<dsize_t>(iscrowd_row.size()), 1}), &iscrowd));
-    data_schema_->column(2).type(), reinterpret_cast<unsigned char *>(&category_id_row[0])));
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(area_row, TensorShape({static_cast<dsize_t>(area_row.size()), 1}), &area));
-    &iscrowd, data_schema_->column(3).tensorImpl(), TensorShape({static_cast<dsize_t>(iscrowd_row.size()), 1}),
-    data_schema_->column(3).type(), reinterpret_cast<unsigned char *>(&iscrowd_row[0])));
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(
-    &area, data_schema_->column(4).tensorImpl(), TensorShape({static_cast<dsize_t>(area_row.size()), 1}),
-    data_schema_->column(4).type(), reinterpret_cast<unsigned char *>(&area_row[0])));
   (*trow) = TensorRow(
     row_id, {std::move(image), std::move(coordinate), std::move(category_id), std::move(iscrowd), std::move(area)});
   return Status::OK();
@@ -596,7 +589,7 @@ Status CocoOp::LaunchThreadsAndInitOp() {
 }
 
 Status CocoOp::ReadImageToTensor(const std::string &path, const ColDescriptor &col, std::shared_ptr<Tensor> *tensor) {
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(tensor, path));
+  RETURN_IF_NOT_OK(Tensor::CreateFromFile(path, tensor));
 
   if (decode_ == true) {
     Status rc = Decode(*tensor, tensor);

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/csv_op.cc

@@ -102,18 +102,13 @@ int CsvOp::CsvParser::put_record(char c) {
   std::shared_ptr<Tensor> t;
   switch (column_default_[cur_col_]->type) {
     case CsvOp::INT:
-      Tensor::CreateTensor(&t, TensorImpl::kFlexible, TensorShape::CreateScalar(), DataType(DataType::DE_INT32));
+      Tensor::CreateScalar(std::stoi(s), &t);
-      t->SetItemAt<int32_t>({0}, std::stoi(s));
       break;
     case CsvOp::FLOAT:
-      Tensor::CreateTensor(&t, TensorImpl::kFlexible, TensorShape::CreateScalar(), DataType(DataType::DE_FLOAT32));
+      Tensor::CreateScalar(std::stof(s), &t);
-      t->SetItemAt<float>({0}, std::stof(s));
-      break;
-    case CsvOp::STRING:
-      Tensor::CreateTensor(&t, {s}, TensorShape::CreateScalar());
       break;
     default:
-      Tensor::CreateTensor(&t, {s}, TensorShape::CreateScalar());
+      Tensor::CreateScalar(s, &t);
       break;
   }
   (*tensor_table_)[cur_row_][cur_col_] = std::move(t);

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/generator_op.cc

@@ -129,7 +129,7 @@ Status GeneratorOp::PyRowToTensorRow(py::object py_data, TensorRow *tensor_row)
                     "Generator should return a tuple of numpy arrays.");
     }
     std::shared_ptr<Tensor> tensor;
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&tensor, ret_py_ele.cast<py::array>()));
+    RETURN_IF_NOT_OK(Tensor::CreateFromNpArray(ret_py_ele.cast<py::array>(), &tensor));
     if ((!column_types_.empty()) && (column_types_[i] != DataType::DE_UNKNOWN) &&
         (column_types_[i] != tensor->type())) {
       return Status(StatusCode::kPyFuncException, __LINE__, __FILE__, "Generator type check failed.");

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/image_folder_op.cc

@@ -201,10 +201,8 @@ Status ImageFolderOp::WorkerEntry(int32_t worker_id) {
 // Load 1 TensorRow (image,label) using 1 ImageLabelPair. 1 function call produces 1 TensorTow in a DataBuffer
 Status ImageFolderOp::LoadTensorRow(row_id_type row_id, ImageLabelPair pairPtr, TensorRow *trow) {
   std::shared_ptr<Tensor> image, label;
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&label, data_schema_->column(1).tensorImpl(), data_schema_->column(1).shape(),
+  RETURN_IF_NOT_OK(Tensor::CreateScalar(pairPtr->second, &label));
-                                        data_schema_->column(1).type(),
+  RETURN_IF_NOT_OK(Tensor::CreateFromFile(folder_path_ + (pairPtr->first), &image));
-                                        reinterpret_cast<unsigned char *>(&pairPtr->second)));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&image, folder_path_ + (pairPtr->first)));
 
   if (decode_ == true) {
     Status rc = Decode(image, &image);

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/manifest_op.cc

@@ -185,17 +185,14 @@ Status ManifestOp::LoadTensorRow(row_id_type row_id, const std::pair<std::string
   std::vector<int32_t> label_index(data.second.size());
   (void)std::transform(data.second.begin(), data.second.end(), label_index.begin(),
                        [this](const std::string &label_name) { return label_index_[label_name]; });
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(label_index, &label));
   if (label_index.size() == 1) {
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&label, data_schema_->column(1).tensorImpl(), TensorShape({}),
+    label->Reshape(TensorShape({}));
-                                          data_schema_->column(1).type(),
-                                          reinterpret_cast<unsigned char *>(&label_index[0])));
   } else {
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(
+    label->Reshape(TensorShape(std::vector<dsize_t>(1, label_index.size())));
-      &label, data_schema_->column(1).tensorImpl(), TensorShape(std::vector<dsize_t>(1, label_index.size())),
-      data_schema_->column(1).type(), reinterpret_cast<unsigned char *>(&label_index[0])));
   }
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&image, data.first));
+  RETURN_IF_NOT_OK(Tensor::CreateFromFile(data.first, &image));
   if (decode_ == true) {
     Status rc = Decode(image, &image);
     if (rc.IsError()) {

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/mindrecord_op.cc

@@ -381,15 +381,15 @@ Status MindRecordOp::LoadTensorRow(TensorRow *tensor_row, const std::vector<uint
     auto num_elements = n_bytes / column_data_type_size;
     if (type == DataType::DE_STRING) {
       std::string s{data, data + n_bytes};
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(&tensor, {s}, TensorShape::CreateScalar()));
+      RETURN_IF_NOT_OK(Tensor::CreateScalar(s, &tensor));
     } else if (column.hasShape()) {
       auto new_shape = TensorShape(column.shape());
       RETURN_IF_NOT_OK(column.MaterializeTensorShape(static_cast<int32_t>(num_elements), &new_shape));
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(&tensor, column.tensorImpl(), new_shape, type, data));
+      RETURN_IF_NOT_OK(Tensor::CreateFromMemory(new_shape, type, data, &tensor));
     } else {
       std::vector<dsize_t> shapeDetails = {static_cast<dsize_t>(num_elements)};
       auto new_shape = TensorShape(shapeDetails);
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(&tensor, column.tensorImpl(), new_shape, type, data));
+      RETURN_IF_NOT_OK(Tensor::CreateFromMemory(new_shape, type, data, &tensor));
     }
     tensor_row->push_back(std::move(tensor));
   }

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/mnist_op.cc

@@ -160,12 +160,10 @@ Status MnistOp::WorkerEntry(int32_t worker_id) {
 // Load 1 TensorRow (image,label) using 1 MnistLabelPair.
 Status MnistOp::LoadTensorRow(row_id_type row_id, const MnistLabelPair &mnist_pair, TensorRow *trow) {
   std::shared_ptr<Tensor> image, label;
-  int32_t l = mnist_pair.second;
   // make a copy of cached tensor
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&image, data_schema_->column(0).tensorImpl(), mnist_pair.first->shape(),
+  RETURN_IF_NOT_OK(Tensor::CreateFromTensor(mnist_pair.first, &image));
-                                        mnist_pair.first->type(), mnist_pair.first->GetBuffer()));
+  RETURN_IF_NOT_OK(Tensor::CreateScalar(mnist_pair.second, &label));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&label, data_schema_->column(1).tensorImpl(), data_schema_->column(1).shape(),
+
-                                        data_schema_->column(1).type(), reinterpret_cast<unsigned char *>(&l)));
   (*trow) = TensorRow(row_id, {std::move(image), std::move(label)});
   return Status::OK();
 }
@@ -325,8 +323,8 @@ Status MnistOp::ReadImageAndLabel(std::ifstream *image_reader, std::ifstream *la
       pixels[m] = (pixels[m] == 0) ? 0 : 255;
     }
     std::shared_ptr<Tensor> image;
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&image, data_schema_->column(0).tensorImpl(), img_tensor_shape,
+    RETURN_IF_NOT_OK(Tensor::CreateFromMemory(img_tensor_shape, data_schema_->column(0).type(),
-                                          data_schema_->column(0).type(), reinterpret_cast<unsigned char *>(pixels)));
+                                              reinterpret_cast<unsigned char *>(pixels), &image));
     image_label_pairs_.emplace_back(std::make_pair(image, labels_buf[j]));
   }
   return Status::OK();

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/mnist_op.h

@@ -40,7 +40,7 @@ namespace dataset {
 template <typename T>
 class Queue;
 
-using MnistLabelPair = std::pair<std::shared_ptr<Tensor>, int32_t>;
+using MnistLabelPair = std::pair<std::shared_ptr<Tensor>, uint32_t>;
 
 class MnistOp : public ParallelOp, public RandomAccessOp {
  public:

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/random_data_op.cc

@@ -361,8 +361,7 @@ Status RandomDataOp::CreateRandomRow(int32_t worker_id, TensorRow *new_row) {
       return Status(StatusCode::kUnexpectedError, __LINE__, __FILE__, "Failed to set random bytes for a tensor.");
     }
 
-    RETURN_IF_NOT_OK(
+    RETURN_IF_NOT_OK(Tensor::CreateFromMemory(*new_shape, current_col.type(), buf.get(), &new_tensor));
-      Tensor::CreateTensor(&new_tensor, current_col.tensorImpl(), *new_shape, current_col.type(), buf.get()));
 
     // Add this tensor to the tensor row for output
     (*new_row).push_back(std::move(new_tensor));

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/sampler/python_sampler.cc

@@ -41,7 +41,7 @@ Status PythonSampler::GetNextSample(std::unique_ptr<DataBuffer> *out_buffer) {
       try {
         py::object py_ret = py_sampler_instance.attr("_get_indices")();
         py::array np_sample_ids = py_ret.cast<py::array>();
-        Tensor::CreateTensor(&sample_ids, np_sample_ids);  // copy numpy to tensor
+        Tensor::CreateFromNpArray(np_sample_ids, &sample_ids);  // copy numpy to tensor
 
         if (HasChildSampler()) {
           for (auto it = sample_ids->begin<int64_t>(); it != sample_ids->end<int64_t>(); ++it) {

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/sampler/sampler.cc

@@ -73,9 +73,7 @@ Status Sampler::CreateSamplerTensor(std::shared_ptr<Tensor> *sample_ids, int64_t
     col_desc_ = std::make_unique<ColDescriptor>("sampleIds", DataType(DataType::DE_INT64), TensorImpl::kFlexible, 1);
   }
   TensorShape shape(std::vector<dsize_t>(1, num_elements));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(sample_ids, col_desc_->tensorImpl(), shape, col_desc_->type()));
+  RETURN_IF_NOT_OK(Tensor::CreateEmpty(shape, col_desc_->type(), sample_ids));
-  RETURN_IF_NOT_OK(
-    (*sample_ids)->AllocateBuffer((*sample_ids)->SizeInBytes()));  // allocate memory in case user forgets!
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/text_file_op.cc

@@ -146,7 +146,7 @@ Status TextFileOp::LoadTensor(const std::string &line, std::unique_ptr<TensorQTa
   (*tensor_table)->push_back(std::move(tRow));
 
   std::shared_ptr<Tensor> tensor;
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&tensor, {line}, TensorShape::CreateScalar()));
+  RETURN_IF_NOT_OK(Tensor::CreateScalar(line, &tensor));
   (**tensor_table)[row][0] = std::move(tensor);
   return Status::OK();
 }

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/tf_reader_op.cc

@@ -677,8 +677,7 @@ Status TFReaderOp::LoadFeature(const std::unique_ptr<TensorQTable> *tensor_table
       // into the tensor
       TensorShape current_shape = TensorShape::CreateUnknownRankShape();
       RETURN_IF_NOT_OK(current_col.MaterializeTensorShape(num_elements, &current_shape));
-      RETURN_IF_NOT_OK(
+      RETURN_IF_NOT_OK(Tensor::CreateFromMemory(current_shape, current_col.type(), data_ptr, &ts));
-        Tensor::CreateTensor(&ts, current_col.tensorImpl(), current_shape, current_col.type(), data_ptr));
       break;
     }
     case dataengine::Feature::KindCase::kInt64List: {
@@ -735,7 +734,7 @@ Status TFReaderOp::LoadBytesList(const ColDescriptor &current_col, const dataeng
   if (current_col.type() == DataType::DE_STRING) {
     TensorShape shape = TensorShape::CreateScalar();
     RETURN_IF_NOT_OK(current_col.MaterializeTensorShape(*num_elements, &shape));
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(tensor, bytes_list, shape));
+    RETURN_IF_NOT_OK(Tensor::CreateFromByteList(bytes_list, shape, tensor));
     return Status::OK();
   }
 
@@ -763,7 +762,7 @@ Status TFReaderOp::LoadBytesList(const ColDescriptor &current_col, const dataeng
   // know how many elements there are and the total bytes, create tensor here:
   TensorShape current_shape = TensorShape::CreateScalar();
   RETURN_IF_NOT_OK(current_col.MaterializeTensorShape((*num_elements) * pad_size, &current_shape));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(tensor, bytes_list, current_shape, current_col.type(), pad_size));
+  RETURN_IF_NOT_OK(Tensor::CreateFromByteList(bytes_list, current_shape, current_col.type(), pad_size, tensor));
 
   return Status::OK();
 }
@@ -836,10 +835,7 @@ Status TFReaderOp::LoadIntList(const ColDescriptor &current_col, const dataengin
   // know how many elements there are, create tensor here:
   TensorShape current_shape = TensorShape::CreateUnknownRankShape();
   RETURN_IF_NOT_OK(current_col.MaterializeTensorShape(*num_elements, &current_shape));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(tensor, current_col.tensorImpl(), current_shape, current_col.type()));
+  RETURN_IF_NOT_OK(Tensor::CreateEmpty(current_shape, current_col.type(), tensor));
-
-  // Tensors are lazily allocated, this eagerly allocates memory for the tensor.
-  RETURN_IF_NOT_OK((*tensor)->AllocateBuffer((*tensor)->SizeInBytes()));
 
   int64_t i = 0;
   auto it = (*tensor)->begin<T>();

mindspore/ccsrc/minddata/dataset/engine/datasetops/source/voc_op.cc

@@ -375,7 +375,7 @@ Status VOCOp::LaunchThreadsAndInitOp() {
 }
 
 Status VOCOp::ReadImageToTensor(const std::string &path, const ColDescriptor &col, std::shared_ptr<Tensor> *tensor) {
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(tensor, path));
+  RETURN_IF_NOT_OK(Tensor::CreateFromFile(path, tensor));
   if (decode_ == true) {
     Status rc = Decode(*tensor, tensor);
     if (rc.IsError()) {
@@ -412,18 +412,10 @@ Status VOCOp::ReadAnnotationToTensor(const std::string &path, TensorRow *row) {
       bbox_num++;
     }
   }
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&bbox, data_schema_->column(1).tensorImpl(), TensorShape({bbox_num, 4}),
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(bbox_data, TensorShape({bbox_num, 4}), &bbox));
-                                        data_schema_->column(1).type(),
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(label_data, TensorShape({bbox_num, 1}), &label));
-                                        reinterpret_cast<unsigned char *>(&bbox_data[0])));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(difficult_data, TensorShape({bbox_num, 1}), &difficult));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&label, data_schema_->column(2).tensorImpl(), TensorShape({bbox_num, 1}),
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(truncate_data, TensorShape({bbox_num, 1}), &truncate));
-                                        data_schema_->column(2).type(),
-                                        reinterpret_cast<unsigned char *>(&label_data[0])));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&difficult, data_schema_->column(3).tensorImpl(), TensorShape({bbox_num, 1}),
-                                        data_schema_->column(3).type(),
-                                        reinterpret_cast<unsigned char *>(&difficult_data[0])));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&truncate, data_schema_->column(4).tensorImpl(), TensorShape({bbox_num, 1}),
-                                        data_schema_->column(4).type(),
-                                        reinterpret_cast<unsigned char *>(&truncate_data[0])));
   (*row) = TensorRow({std::move(bbox), std::move(label), std::move(difficult), std::move(truncate)});
   return Status::OK();
 }

mindspore/ccsrc/minddata/dataset/engine/gnn/graph.cc

@@ -57,8 +57,7 @@ Status Graph::CreateTensorByVector(const std::vector<std::vector<T>> &data, Data
   std::shared_ptr<Tensor> tensor;
   size_t m = data.size();
   size_t n = data[0].size();
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(
+  RETURN_IF_NOT_OK(Tensor::CreateEmpty(TensorShape({static_cast<dsize_t>(m), static_cast<dsize_t>(n)}), type, &tensor));
-    &tensor, TensorImpl::kFlexible, TensorShape({static_cast<dsize_t>(m), static_cast<dsize_t>(n)}), type, nullptr));
   auto ptr = tensor->begin<T>();
   for (const auto &id_m : data) {
     CHECK_FAIL_RETURN_UNEXPECTED(id_m.size() == n, "Each member of the vector has a different size");
@@ -310,8 +309,7 @@ Status Graph::GetNodeFeature(const std::shared_ptr<Tensor> &nodes, const std::ve
     dsize_t size = std::accumulate(shape_vec.begin(), shape_vec.end(), 1, std::multiplies<dsize_t>());
     shape = shape.PrependDim(size);
     std::shared_ptr<Tensor> fea_tensor;
-    RETURN_IF_NOT_OK(
+    RETURN_IF_NOT_OK(Tensor::CreateEmpty(shape, default_feature->Value()->type(), &fea_tensor));
-      Tensor::CreateTensor(&fea_tensor, TensorImpl::kFlexible, shape, default_feature->Value()->type(), nullptr));
 
     dsize_t index = 0;
     for (auto node_itr = nodes->begin<NodeIdType>(); node_itr != nodes->end<NodeIdType>(); ++node_itr) {
@@ -358,8 +356,7 @@ Status Graph::GetEdgeFeature(const std::shared_ptr<Tensor> &edges, const std::ve
     dsize_t size = std::accumulate(shape_vec.begin(), shape_vec.end(), 1, std::multiplies<dsize_t>());
     shape = shape.PrependDim(size);
     std::shared_ptr<Tensor> fea_tensor;
-    RETURN_IF_NOT_OK(
+    RETURN_IF_NOT_OK(Tensor::CreateEmpty(shape, default_feature->Value()->type(), &fea_tensor));
-      Tensor::CreateTensor(&fea_tensor, TensorImpl::kFlexible, shape, default_feature->Value()->type(), nullptr));
 
     dsize_t index = 0;
     for (auto edge_itr = edges->begin<EdgeIdType>(); edge_itr != edges->end<EdgeIdType>(); ++edge_itr) {

mindspore/ccsrc/minddata/dataset/engine/gnn/graph_loader.cc

@@ -125,7 +125,7 @@ Status GraphLoader::LoadNode(const std::vector<uint8_t> &col_blob, const mindrec
     (*feature_map)[node_type].insert(ind);
     if ((*default_feature)[ind] == nullptr) {
       std::shared_ptr<Tensor> zero_tensor;
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(&zero_tensor, TensorImpl::kFlexible, tensor->shape(), tensor->type()));
+      RETURN_IF_NOT_OK(Tensor::CreateEmpty(tensor->shape(), tensor->type(), &zero_tensor));
       RETURN_IF_NOT_OK(zero_tensor->Zero());
       (*default_feature)[ind] = std::make_shared<Feature>(ind, zero_tensor);
     }
@@ -151,7 +151,7 @@ Status GraphLoader::LoadEdge(const std::vector<uint8_t> &col_blob, const mindrec
     (*feature_map)[edge_type].insert(ind);
     if ((*default_feature)[ind] == nullptr) {
       std::shared_ptr<Tensor> zero_tensor;
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(&zero_tensor, TensorImpl::kFlexible, tensor->shape(), tensor->type()));
+      RETURN_IF_NOT_OK(Tensor::CreateEmpty(tensor->shape(), tensor->type(), &zero_tensor));
       RETURN_IF_NOT_OK(zero_tensor->Zero());
       (*default_feature)[ind] = std::make_shared<Feature>(ind, zero_tensor);
     }
@@ -170,9 +170,9 @@ Status GraphLoader::LoadFeatureTensor(const std::string &key, const std::vector<
     key, col_blob, col_jsn, &data, &data_ptr, &n_bytes, &col_type, &col_type_size, &column_shape);
   CHECK_FAIL_RETURN_UNEXPECTED(rs == mindrecord::SUCCESS, "fail to load column" + key);
   if (data == nullptr) data = reinterpret_cast<const unsigned char *>(&data_ptr[0]);
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(tensor, TensorImpl::kFlexible,
+  RETURN_IF_NOT_OK(Tensor::CreateFromMemory(std::move(TensorShape({static_cast<dsize_t>(n_bytes / col_type_size)})),
-                                        std::move(TensorShape({static_cast<dsize_t>(n_bytes / col_type_size)})),
+                                            std::move(DataType(mindrecord::ColumnDataTypeNameNormalized[col_type])),
-                                        std::move(DataType(mindrecord::ColumnDataTypeNameNormalized[col_type])), data));
+                                            data, tensor));
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/include/tensor.h

@@ -33,6 +33,7 @@
 #include "pybind11/stl.h"
 #endif
 
+#include "common/utils.h"
 #include "minddata/dataset/core/constants.h"
 #include "minddata/dataset/core/data_type.h"
 #include "minddata/dataset/core/tensor_shape.h"
@@ -50,170 +51,155 @@ class Allocator;
 
 using CharAllocPtr = std::unique_ptr<Allocator<unsigned char>>;
 using TensorAllocPtr = std::shared_ptr<Allocator<Tensor>>;  // An allocator shared_ptr for Tensors
+using offset_t = uint32_t;                                  // type of offset values to store strings locations
+using TensorPtr = std::shared_ptr<Tensor>;
 
 class Tensor {
  public:
   Tensor() = delete;
-
-  // Create a new tensor, does not internally allocate storage. This constructor is protected, use CreateTensor.
-  // @note The shape and type information should be known and valid.
-  // @param shape TensorShape
-  // @param type DataType
-  Tensor(const TensorShape &shape, const DataType &type);
-
-  // Create a new tensor, allocates storage and copies in data. This constructor is protected, use CreateTensor.
-  // @note The buffer should be valid and the shape and type information should be known and valid.
-  // @param shape TensorShape
-  // @param type DataType
-  // @param data unsigned char*, pointer to the data.
-  Tensor(const TensorShape &shape, const DataType &type, const unsigned char *data);
-
-  Tensor(const TensorShape &shape, const DataType &type, const unsigned char *data, const dsize_t &length);
-
   Tensor(const Tensor &other) = delete;
-
   Tensor &operator=(const Tensor &other) = delete;
 
+  /// Create a tensor using shape and type. This constructor should not be used directly, use CreateFromTensor instead
+  /// \note The shape and type information should be known and valid
+  /// \note The constructor does not allocate data
+  /// \param shape TensorShape
+  /// \param type DataType
+  Tensor(const TensorShape &shape, const DataType &type);
+
+  /// Move constructor
+  /// \param other Tensor to be moved
   Tensor(Tensor &&other) noexcept;
 
+  /// Move assigment operator
+  /// \param other Tensor to be moved
   Tensor &operator=(Tensor &&other) noexcept;
 
-  Status AllocateBuffer(const dsize_t &length);
+  /// Create a numeric tensor with type and shape. Items of the tensor would be uninitialized.
+  /// \param[in] shape shape of the output tensor
+  /// \param[in] type type of the output tensor
+  /// \param[out] out Generated tensor
+  /// \return Status code
+  static Status CreateEmpty(const TensorShape &shape, const DataType &type, TensorPtr *out);
 
-  // type of offest values to store strings information
+  /// Create a numeric tensor from a pointer in memory. Length of the source data is determined from the shape and type.
-  using offset_t = uint32_t;
+  /// Data will be copied into the new created tensor.
-  // const of the size of the offset variable
+  /// \param[in] shape shape of the output tensor
-  static constexpr uint8_t kOffsetSize = sizeof(offset_t);
+  /// \param[in] type type of the output tensor
-  // Tensor base class which holds the data in an unsigned char* buffer.
+  /// \param[in] src pointer to the source data
+  /// \param[out] out Generated tensor
+  /// \return Status code
+  static Status CreateFromMemory(const TensorShape &shape, const DataType &type, const uchar *src, TensorPtr *out);
 
-  // Construct  a scalar string Tensor
+  /// Create a tensor from a pointer in memory and length. Data will be copied into the new created tensor.
-  explicit Tensor(const std::string &str) : Tensor(std::vector<std::string>{str}, TensorShape::CreateScalar()) {}
+  /// \param[in] shape shape of the output tensor
+  /// \param[in] type type of the output tensor
+  /// \param[in] src pointer to the source data
+  /// \param[in] length length of the src data
+  /// \param[out] out Generated tensor
+  /// \return Status code
+  static Status CreateFromMemory(const TensorShape &shape, const DataType &type, const uchar *src,
+                                 const dsize_t &length, TensorPtr *out);
 
-  // Construct a tensor from  a list of strings. Reshape the tensor with `shape` if given, otherwise assume the shape is
+  /// Create a copy of the input tensor
-  // the size of the vector `strings`.
+  /// \param[in] in original tensor to be copied
-  // The memory layout of a Tensor of strings consists of the Offset_array followed by the strings.
+  /// \param[out] out output tensor to be generated
-  // Thr offset array will store one extra value to find the length of the last string.
+  /// \return Status
-  // OFFSET1, OFFSET2, ..., OFFSETn+1, STRING1, STRING2, ..., STRINGn
+  static Status CreateFromTensor(const TensorPtr &in, TensorPtr *out) {
-  // The value of each offset is the start index of the corresponding string
+    return CreateFromMemory(in->shape(), in->type(), in->GetBuffer(), in->SizeInBytes(), out);
-  // Offsets is of type offest_t
-  // strings will ne null-terminated
-  // example: Tensor(['abc', 'de'], shape={2}, type=DE_STRING)
-  // |----------------------------------------------------------------|
-  // |             OFFSET ARRAY           |            STRINGS        |
-  // | bytes 0-3 | bytes 3-6 | bytes 7-10 | bytes 11-14 | bytes 15-17 |
-  // |     11    |    15     |     18     |     abc\0   |      de\0   |
-  // |----------------------------------------------------------------|
-  explicit Tensor(const std::vector<std::string> &strings,
-                  const TensorShape &shape = TensorShape::CreateUnknownRankShape());
-
-  // Same as Tensor(vector<string>) but the input is protobuf bytelist
-  explicit Tensor(const dataengine::BytesList &bytes_list,
-                  const TensorShape &shape = TensorShape::CreateUnknownRankShape());
-
-  // A static factory method to create the given flavour of derived Tensor
-  // Returns the base class reference for the Tensor.
-  // @param ptr output argument to hold the created Tensor of given tensor_impl
-  // @param tensor_impl - which implementation of Tensor
-  // @param shape - shape of the tensor
-  // @param type - datatype of the tensor
-  // @param data - data to be copied to Tensor new allocation
-  // @return Status Code
-  static Status CreateTensor(std::shared_ptr<Tensor> *, TensorImpl tensor_impl, const TensorShape &shape, DataType type,
-                             const unsigned char *data = nullptr);
-
-  // Create a copy of the input tensor
-  // @param out [out] output tensor to be generated
-  // @param in [in] orginal tensor to be copied
-  // @return Status
-  static Status CreateTensor(std::shared_ptr<Tensor> *out, const std::shared_ptr<Tensor> &in) {
-    const TensorAlloc *alloc = GlobalContext::Instance()->tensor_allocator();
-    *out = std::allocate_shared<Tensor>(*alloc, in->shape(), in->type(), in->GetBuffer(), in->SizeInBytes());
-    return Status::OK();
   }
 
 #ifdef ENABLE_PYTHON
-  // A static factory method to create a Tensor from a given py::array.
+  /// Create a Tensor from a given py::array
-  // @param ptr output argument to hold the created Tensor
+  /// \param[in] arr py::array
-  // @param arr py::array
+  /// \param[out] out Created tensor
-  // @return Status Code
+  /// \return Status Code
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, py::array arr);
+  static Status CreateFromNpArray(const py::array &arr, TensorPtr *out);
-
-  // Helper function to create a tensor from Numpy of strings
-  static Status CreateTensorFromNumpyString(std::shared_ptr<Tensor> *ptr, py::array arr);
 #endif
 
-  // A static factory method to create a Tensor from a given list of strings.
+  /// Create a tensor of type DE_STRING from a BytesList.
-  // @param ptr output argument to hold the created Tensor
+  /// \param[in] bytes_list protobuf's Bytelist
-  // @param strings elements of the tensor
+  /// \param[in] shape shape of the outout tensor
-  // @param shape shape of the tensor
+  /// \param[out] out created Tensor
-  // @return Status Code
+  /// \return Status Code
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const std::vector<std::string> &strings,
+  static Status CreateFromByteList(const dataengine::BytesList &bytes_list, const TensorShape &shape, TensorPtr *out);
-                             const TensorShape &shape = TensorShape::CreateUnknownRankShape());
 
-  // create tensor from protobuf bytelist with strings
+  /// Create a tensor of type UINT8 or INT8 from a BytesList.
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const dataengine::BytesList &bytes_list,
+  /// The tensor will be padded with ' ' to reach the required pad_size.
-                             const TensorShape &shape);
+  /// \param[in] bytes_list protobuf's Bytelist
+  /// \param[in] shape shape of the output tensor
+  /// \param[in] type type of created tensor. Should be DE_UINT8 or INT8
+  /// \param[in] pad_size The size of the tensor after padding
+  /// \param[out] out created Tensor
+  /// \return Status Code
+  static Status CreateFromByteList(const dataengine::BytesList &bytes_list, const TensorShape &shape,
+                                   const DataType &type, dsize_t pad_size, TensorPtr *out);
 
-  // A static factory method to create a Tensor from a given list of numbers.
+  /// Create a Tensor from a given list of values.
-  // @param ptr output argument to hold the created Tensor
+  /// \tparam type of the values to be inserted.
-  // @param items elements of the tensor
+  /// \param[in] items elements of the tensor
-  // @param shape shape of the tensor
+  /// \param[in] shape shape of the output tensor
-  // @return Status Code
+  /// \param[out] out output argument to hold the created Tensor
+  /// \return Status Code
   template <typename T>
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const std::vector<T> &items,
+  static Status CreateFromVector(const std::vector<T> &items, const TensorShape &shape, TensorPtr *out) {
-                             const TensorShape &shape_req = TensorShape::CreateUnknownRankShape()) {
+    CHECK_FAIL_RETURN_UNEXPECTED(
+      items.size() == shape.NumOfElements(),
+      "Number of elements in the vector does not match the number of elements of the shape required");
     DataType type = DataType::FromCType<T>();
+    // if items is empty, items_ptr would be nullptr. CreateFromMemory will handle this case.
     auto items_ptr = reinterpret_cast<const uchar *>(&items[0]);
-    TensorShape shape = shape_req;
+    return CreateFromMemory(shape, type, items_ptr, out);
-    if (!shape.known()) {
-      shape = TensorShape({static_cast<dsize_t>(items.size())});
-    }
-    return CreateTensor(ptr, TensorImpl::kFlexible, shape, type, items_ptr);
   }
 
-  // A static factory method to create a Tensor from a given number.
+  /// Create a 1D Tensor from a given list of values.
-  // @param ptr output argument to hold the created Tensor
+  /// \tparam type of the values to be inserted.
-  // @param item value
+  /// \param[in] items elements of the tensor
-  // @return Status Code
+  /// \param[out] out output argument to hold the created Tensor
+  /// \return Status Code
   template <typename T>
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const T &item) {
+  static Status CreateFromVector(const std::vector<T> &items, TensorPtr *out) {
-    return CreateTensor<T>(ptr, {item}, TensorShape::CreateScalar());
+    return CreateFromVector(items, TensorShape({static_cast<dsize_t>(items.size())}), out);
   }
 
-  // Create tensor from protobuf bytelist with uint8 or int8 types
+  /// Create a numeric scalar Tensor from the given value.
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const dataengine::BytesList &bytes_list,
+  /// \tparam T type of value
-                             const TensorShape &shape, const DataType &type, dsize_t pad_size);
+  /// \param[in] item value
+  /// \param[out] out Created tensor
+  /// \return Status code
+  template <typename T>
+  static Status CreateScalar(const T &item, TensorPtr *out) {
+    DataType type = DataType::FromCType<T>();
+    auto item_ptr = reinterpret_cast<const uchar *>(&item);
+    return CreateFromMemory(TensorShape::CreateScalar(), type, item_ptr, out);
+  }
 
-  static Status CreateTensor(std::shared_ptr<Tensor> *ptr, const std::string &path);
+  /// Create a tensor from a binary file on disk.
+  /// \param[in] path file to be read
+  /// \param[out] out Created Tensor
+  /// \return Status code
+  static Status CreateFromFile(const std::string &path, TensorPtr *out);
 
-  // Copy raw data of a array based on shape and strides to the destination pointer
+  /// Destruct the tensor and release the memory using the allocator
-  // @param dst Pointer to the destination array where the content is to be copied
-  // @param src Pointer to the source of strided array to be copied
-  // @param shape - shape of the source array
-  // @param strides - strides of the source array
-  // @param type_size - number of bytes needed to store one array element's type
-  // @return Status Code
-  static Status CopyStridedArray(unsigned char *dst, unsigned char *src, std::vector<dsize_t> shape,
-                                 std::vector<dsize_t> strides, uint8_t type_size);
-
-  // Release the memory using the allocator
   virtual ~Tensor();
 
-  // compare the tensor shape and data
+  /// Equality operator. compares tensor shape, type and data
+  /// \param[in] rhs Tensor to be compared with
+  /// \return bool
   bool operator==(const Tensor &rhs) const;
 
   bool operator!=(const Tensor &rhs) const { return !((*this) == rhs); }
 
-  // Get item located at `index`, caller needs to provide the type.
+  /// Get item located at `index`, caller needs to provide the type.
-  // @tparam T
+  /// \tparam T
-  // @param index vector<dsize_t>
+  /// \param[in] index vector<dsize_t>
-  // @return return the item specified at index
+  /// \return return the item specified at index
   template <typename T>
   Status GetItemAt(T *o, const std::vector<dsize_t> &index) const;
 
-  // Get string located at `index`.
+  /// Get string located at `index`.
-  // @param index vector<dsize_t>
+  /// \param[in] index vector<dsize_t>
-  // @return return std::string_view specified at index
+  /// \return return std::string_view specified at index
   Status GetItemAt(std::string_view *o, const std::vector<dsize_t> &index) const;
 
   template <typename T>
@@ -225,22 +211,21 @@ class Tensor {
   template <typename T>
   Status GetFloatAt(T *o, const std::vector<dsize_t> &index) const;
 
-  // set item at location specified by index
+  /// set item at location specified by index
-  // @tparam `T`
+  /// \tparam `T`
-  // @param index
+  /// \param[in] index
-  // @param value of type `T`
+  /// \param[in] value of type `T`
   template <typename T>
   Status SetItemAt(const std::vector<dsize_t> &index, const T &value) {
-    RETURN_IF_NOT_OK(AllocateBuffer(SizeInBytes()));
     T *ptr = nullptr;
     RETURN_IF_NOT_OK(GetItemPtr<T>(&ptr, index));
     *ptr = value;
     return Status::OK();
   }
 
-  // set string item at location specified by index
+  /// set string item at location specified by index
-  // @param index
+  /// \param[in] index
-  // @param value of type std::string
+  /// \param[in] value of type std::string
   Status SetItemAt(const std::vector<dsize_t> &index, const std::string &value) {
     RETURN_UNEXPECTED_IF_NULL(data_);
     uchar *ptr = nullptr;
@@ -253,7 +238,8 @@ class Tensor {
 
     return Status::OK();
   }
-  // fill tensor with Zeros. Does not support strings.
+
+  /// fill tensor with Zeros. Does not support strings.
   Status Zero() {
     CHECK_FAIL_RETURN_UNEXPECTED(type_ != DataType::DE_STRING, "Cannot use Zero on tensor of strings..");
     dsize_t size = SizeInBytes();
@@ -262,13 +248,12 @@ class Tensor {
     return Status::OK();
   }
 
-  // Fill all elements in the Tensor with the given value of type `T`.  Does not support strings.
+  /// Fill all elements in the Tensor with the given value of type `T`.  Does not support strings.
-  // @tparam T
+  /// \tparam T
-  // @param value
+  /// \param value[in]
   template <typename T>
   Status Fill(const T &value) {
     CHECK_FAIL_RETURN_UNEXPECTED(type_ != DataType::DE_STRING, "Cannot use fill on tensor of strings.");
-    RETURN_IF_NOT_OK(AllocateBuffer(SizeInBytes()));
     int64_t cellSize = type_.SizeInBytes();
     if ((data_ != nullptr) && type_.IsCompatible<T>()) {
       for (dsize_t i = 0; i < Size(); i++) {
@@ -283,91 +268,86 @@ class Tensor {
     }
   }
 
-  // Getter function for shape
+  /// Getter function for shape
-  // @return
+  /// \return
   const TensorShape &shape() const { return shape_; }
 
   /// Check if tensor has data
   /// \return bool - true if tensor is empty
-  bool HasData() const;
+  bool HasData() const { return data_ != nullptr; }
 
-  // Reshape the tensor. The given shape should have the same number of elements in the Tensor
+  /// Reshape the tensor. The given shape should have the same number of elements in the Tensor
-  // @param shape
+  /// \param shape
   virtual Status Reshape(const TensorShape &shape);
 
-  // @return number of elements in this tensor
+  /// \return number of elements in this tensor
   dsize_t Size() const { return shape().NumOfElements(); }
 
-  // @return the number of bytes this tensor is needs
+  /// \return the number of bytes this tensor is needs
   dsize_t SizeInBytes() const {
     if (data_end_ == nullptr) return type_.SizeInBytes() * shape_.NumOfElements();
     return data_end_ - data_;
   }
 
-  // @return the rank of the tensor
+  /// \return the rank of the tensor
   dsize_t Rank() const { return shape().Rank(); }
 
-  // Get the starting memory address as a constant for the data of the tensor.  This potentially
+  /// Get the starting memory address as a constant for the data of the tensor.  This potentially
-  // drives an allocation if the data area.
+  /// drives an allocation if the data area.
-  // @return const unsigned char*
+  /// \return const unsigned char*
-  const unsigned char *GetBuffer() const;
+  const unsigned char *GetBuffer() const { return data_; }
 
-  // Skip the offsets and returns the start of the buffer where the real strings is stored. Caller needs to check if the
+  /// Getter of the type
-  // tensor's type is a string, otherwise undefined address would be returned.
+  /// \return
-  // @return address of the first string of the tensor.
-  uchar *GetStringsBuffer() const { return data_ + kOffsetSize * shape_.NumOfElements() + kOffsetSize; }
-
-  // Getter of the type
-  // @return
   DataType type() const { return type_; }
 
-  // Provide stream operator for displaying it
+  /// Provide stream operator for displaying it
-  // @param output stream
+  /// \param output stream
-  // @param so the Tensor object to be printed
+  /// \param so the Tensor object to be printed
-  // @return output stream
+  /// \return output stream
   friend std::ostream &operator<<(std::ostream &out, const Tensor &so) {
     so.Print(out);
     return out;
   }
 
-  // Invalidate this Tensor by setting the type and shape to unknown and MData to null.
+  /// Invalidate this Tensor by setting the type and shape to unknown and MData to null.
-  // Calling this method will make the Tensor and its data inaccessible, use it with caution.
+  /// Calling this method will make the Tensor and its data inaccessible, use it with caution.
   void Invalidate();
 
-  // Copy input tensor into self at the location index.
+  /// Copy input tensor into self at the location index.
-  // Index is a vector of axises which can be incomplete:
+  /// Index is a vector of axises which can be incomplete:
-  // Ex: shape <2,3>, inserting into index {0} will replace the first row. index {1,2} will replace the last cell.
+  /// Ex: shape <2,3>, inserting into index {0} will replace the first row. index {1,2} will replace the last cell.
-  // @param index
+  /// \param index
-  // @param input
+  /// \param input
-  // @return Status code
+  /// \return Status code
   Status InsertTensor(const std::vector<dsize_t> &index, const std::shared_ptr<Tensor> &input);
 
-  // Find the address of the given index. Used in InsertTensor.
+  /// Find the address of the given index. Used in InsertTensor.
-  // Example:
+  /// Example:
-  //      Tensor t= [[1,2],[3,4]] , StartAddrOfIndex({0}) -> &1
+  ///      Tensor t= [[1,2],[3,4]] , StartAddrOfIndex({0}) -> &1
-  // @param index  incomplete index
+  /// \param index  incomplete index
-  // @param output: startAddrofIndex
+  /// \param output: startAddrofIndex
-  // @param output: remaining
+  /// \param output: remaining
-  // @return Status code
+  /// \return Status code
   Status StartAddrOfIndex(std::vector<dsize_t> ind, uchar **start_addr_of_index, TensorShape *remaining);
 
-  // Expand the shape of the Tensor with one extra dimension.
+  /// Expand the shape of the Tensor with one extra dimension.
-  // For example, if the shape is <512,512,3>:
+  /// For example, if the shape is <512,512,3>:
-  //     *- ExpandDim(0) gives: <1,512,512,3>
+  ///     *- ExpandDim(0) gives: <1,512,512,3>
-  //     *- ExpandDim(1) gives: <512,1,512,3>
+  ///     *- ExpandDim(1) gives: <512,1,512,3>
-  //     *- ExpandDim(3) gives: <512,512,3,1>
+  ///     *- ExpandDim(3) gives: <512,512,3,1>
-  // @param axis location of the dim
+  /// \param axis location of the dim
   virtual Status ExpandDim(const dsize_t &axis);
 
   virtual void Squeeze();
 
-  // Calculates the strides of the Tensor
+  /// Calculates the strides of the Tensor
-  // Ex: Tensor of shape <4,2,2> and type DE_UINT8 (1 byte)
+  /// Ex: Tensor of shape <4,2,2> and type DE_UINT8 (1 byte)
-  // The strides will be {6,2,1}.
+  /// The strides will be {6,2,1}.
-  // Ex: Tensor of shape <4,2,2> and type DE_UINT32 (4 byte)
+  /// Ex: Tensor of shape <4,2,2> and type DE_UINT32 (4 byte)
-  // The strides will be {24,8,4}.
+  /// The strides will be {24,8,4}.
-  // @return vector of integers
+  /// \return vector of integers
-  std::vector<dsize_t> Strides();
+  std::vector<dsize_t> Strides() const;
 
   std::string ToString() {
     std::stringstream ss;
@@ -375,26 +355,26 @@ class Tensor {
     return ss.str();
   }
 
-  // Handle negative indices.
+  /// Handle negative indices.
   static inline dsize_t HandleNeg(dsize_t index, dsize_t length) { return (index < 0) ? (index + length) : index; }
 
-  // Slice tensor bases on the given indicies. Copy the sliced data into out tensor. Only rank1 tensors are supported.
+  /// Slice tensor bases on the given indicies. Copy the sliced data into out tensor. Only rank1 tensors are supported.
-  // Based on the type of tensor, SliceNumeric or SliceString will be called
+  /// Based on the type of tensor, SliceNumeric or SliceString will be called
-  // @param out Tensor
+  /// \param[out] out Tensor
-  // @param indices vector of indices
+  /// \param[in] indices vector of indices
-  // @return Status error code
+  /// \return Status error code
-  Status Slice(std::shared_ptr<Tensor> *out, const std::vector<dsize_t> &indices);
+  Status Slice(TensorPtr *out, const std::vector<dsize_t> &indices);
 
-  // Slice numeric tensors.
+  /// Slice numeric tensors.
-  Status SliceNumeric(std::shared_ptr<Tensor> *out, const std::vector<dsize_t> &indices);
+  Status SliceNumeric(TensorPtr *out, const std::vector<dsize_t> &indices);
 
-  // Slice string tensors
+  /// Slice string tensors
-  Status SliceString(std::shared_ptr<Tensor> *out, const std::vector<dsize_t> &indices);
+  Status SliceString(TensorPtr *out, const std::vector<dsize_t> &indices);
 
 #ifdef ENABLE_PYTHON
-  // Constructs numpy array from input tensor
+  /// Constructs numpy array from input tensor
-  // @param data this data is the location of python data
+  /// \param[in] data this data is the location of python data
-  // @return Status code
+  /// \return Status code
   Status GetDataAsNumpy(py::array *data);
 
   Status GetDataAsNumpyStrings(py::array *data);
@@ -402,12 +382,12 @@ class Tensor {
   static Status GetBufferInfo(Tensor *t, py::buffer_info *out);
 #endif
 
-  // Concatenate based on given tensor, can fill in current tensor with a smaller one, unlike InsertTensor
+  /// Concatenate based on given tensor, can fill in current tensor with a smaller one, unlike InsertTensor
   Status Concatenate(const std::vector<dsize_t> &index, const std::shared_ptr<Tensor> &input);
 
-  // TensorIterator is a linear iterator that can be used to iterate over the elements of the Tensor
+  /// TensorIterator is a linear iterator that can be used to iterate over the elements of the Tensor
-  // The order  elements  is as the memory layout (i.e., row-major) [[1,2,3],[4,5,6] --> 1,2,3,4,5,6
+  /// The order  elements  is as the memory layout (i.e., row-major) [[1,2,3],[4,5,6] --> 1,2,3,4,5,6
-  // @tparam T type of values in the Tensor Iterator
+  /// \tparam T type of values in the Tensor Iterator
   template <typename T, bool = true>
   class TensorIterator {
    public:
@@ -498,7 +478,7 @@ class Tensor {
   };
 
   // Specialization of TensorIterator for strings. It returns std::string_view for every item.
-  // @tparam DUMMY, used to mbe able to specialize the inner class
+  // \tparam DUMMY, used to mbe able to specialize the inner class
   template <bool DUMMY>
   class TensorIterator<std::string_view, DUMMY> {
    public:
@@ -585,84 +565,192 @@ class Tensor {
     const char *data_;
   };
 
-  // Return a TensorIterator that points to the start of the Tensor.
+  /// Return a TensorIterator that points to the start of the Tensor.
-  // It's the user responsibility to use the correct type that matches the Tensor type
+  /// It's the user responsibility to use the correct type that matches the Tensor type
-  // @param T The type of values in the Tensor
+  /// \tparam T The type of values in the Tensor
-  // @return TensorIterator
+  /// \return TensorIterator
   template <typename T>
   TensorIterator<T> begin() {
-    AllocateBuffer(SizeInBytes());
     return TensorIterator<T>(data_);
   }
 
-  // Return a linear iterator that points to the place after the last element of the Tensor.
+  /// Return a linear iterator that points to the place after the last element of the Tensor.
-  // @tparam T The type of values in the Tensor
+  /// \tparam T The type of values in the Tensor
-  // @return TensorIterator
+  /// \return TensorIterator
   template <typename T>
   TensorIterator<T> end() {
     return TensorIterator<T>(data_end_);
   }
 
-  // Copies the last dimension at `index` from Tensor `src` to this Tensor.
+  /// Copies the last dimension at `index` from Tensor `src` to this Tensor.
-  // @param src Tensor
+  /// \param[in] src Tensor
-  // @param index vector to the start of the dimension. The last dim should be 0
+  /// \param[in] index vector to the start of the dimension. The last dim should be 0
-  // @return Status
+  /// \return Status
   Status CopyLastDimAt(const std::shared_ptr<Tensor> &src, const std::vector<dsize_t> &index);
 
  protected:
-  // Get the starting memory address for the data of the tensor.  This potentially
+  /// Allocate memory for the tensor using the data_allocator
-  // drives an allocation if the data is null.
+  /// \param[in] length number of bytes to be allocated
-  // @return unsigned char*
+  /// \return Error Status
-  unsigned char *GetMutableBuffer();
+  Status AllocateBuffer(const dsize_t &length);
 
-  // A function that prints Tensor recursively, first called by print
+  /// Get the starting memory address for the data of the tensor.  This potentially
-  // @param out
+  /// drives an allocation if the data is null.
-  // @param cur_dim
+  /// \return unsigned char*
-  // @param cur_index
+  unsigned char *GetMutableBuffer() { return data_; }
+
+  /// A function that prints Tensor recursively, first called by print
+  /// \param[in] out
+  /// \param[in] cur_dim
+  /// \param[in] cur_index
   void PrintRecursive(std::ostream &out, int32_t cur_dim, const std::vector<dsize_t> &cur_index) const;
 
-  // A function that prints info about the tensor
+  /// A function that prints info about the tensor
-  // @param out output stream
+  /// \param[out] out output stream
   void Print(std::ostream &out) const;
 
-  // A function that print the value as specified by its index
+  /// A function that print the value as specified by its index
-  // @param index vector representing the index
+  /// \param[in] index vector representing the index
-  // @param out
+  /// \param[out] out
   void PrintItemAt(const std::vector<dsize_t> &index, std::ostream &out) const;
 
-  // Get pointer to item located at `index`, caller needs to provide the type.
+  /// Get pointer to item located at `index`, caller needs to provide the type.
-  // @tparam T
+  /// \tparam T
-  // @param index vector<dsize_t>
+  /// \param[in] index vector<dsize_t>
-  // @return return a pointer to the item specified at index of type `T`
+  /// \return return a pointer to the item specified at index of type `T`
   template <typename T>
   Status GetItemPtr(T **, const std::vector<dsize_t> &index) const;
 
-  // Get pointer to string located at `index` and the length of string
+  /// Get pointer to string located at `index` and the length of string
-  // @param index vector<dsize_t>
+  /// \param[in] index vector<dsize_t>
-  // @return return a pointer to the string specified at index and the length of the string
+  /// \return return a pointer to the string specified at index and the length of the string
   Status GetItemPtr(uchar **, const std::vector<dsize_t> &index, offset_t *length = nullptr) const;
 
-  // Given a flat index of an item string, return the start and length of the item
+  /// Given a flat index of an item string, return the start and length of the item
-  // @param index flat index of the item
+  /// \param[in] index flat index of the item
-  // @return start address of the ths string
+  /// \param[out] start address of the ths string
-  // @return length of the string
+  /// \param[out] length of the string
   Status GetStringAt(dsize_t index, uchar **string_start, offset_t *length) const;
 
-  // all access to shape_ should be via shape
+  /// Skip the offsets and returns the start of the buffer where the real strings is stored. Caller needs to check if
+  /// the tensor's type is a string, otherwise undefined address would be returned. \return address of the first string
+  /// of the tensor.
+  uchar *GetStringsBuffer() const { return data_ + kOffsetSize * shape_.NumOfElements() + kOffsetSize; }
+
+  /// all access to shape_ should be via shape
   TensorShape shape_;
-  // data type of tensor
+  /// data type of tensor
   DataType type_;
-  // pointer to the start of the physical data
+  /// pointer to the start of the physical data
   unsigned char *data_;
-  // An allocator for data_
+  /// An allocator for data_
   CharAllocPtr data_allocator_;
-  // pointer to the end of the physical data
+  /// pointer to the end of the physical data
   unsigned char *data_end_ = nullptr;
+
+ private:
+  /// Helper function to create a tensor from Numpy array of strings
+  /// \param[in] arr Numpy array
+  /// \param[out] out Created Tensor
+  /// \return Status
+  static Status CreateFromNpString(py::array arr, TensorPtr *out);
+
+  /// Copy raw data of a array based on shape and strides to the destination pointer
+  /// \param dst [out] Pointer to the destination array where the content is to be copied
+  /// \param[in] src Pointer to the source of strided array to be copied
+  /// \param[in] shape shape of the source array
+  /// \param[in] strides strides of the source array
+  /// \param[in] type_size number of bytes needed to store one array element's type
+  /// \return Status Code
+  static Status CopyStridedArray(unsigned char *dst, unsigned char *src, std::vector<dsize_t> shape,
+                                 std::vector<dsize_t> strides, uint8_t type_size);
+
+  /// const of the size of the offset variable
+  static constexpr uint8_t kOffsetSize = sizeof(offset_t);
 };
 template <>
 inline Tensor::TensorIterator<std::string_view> Tensor::end<std::string_view>() {
   return TensorIterator<std::string_view>(data_, shape_.NumOfElements());
 }
+
+/// Create a Tensor from a given list of strings.
+/// @note: The memory layout of a Tensor of strings consists of the Offset_array followed by the strings.
+/// The offset array will store one extra value to find the length of the last string.
+/// OFFSET_1, OFFSET_2, ..., OFFSET_n+1, STRING_1, STRING_2, ..., STRING_n
+/// The value of each offset is the start index of the corresponding string
+/// Offsets is of type offset_t
+/// strings will ne null-terminated
+/// example: Tensor(['abc', 'de'], shape={2}, type=DE_STRING)
+/// |----------------------------------------------------------------|
+/// |             OFFSET ARRAY           |            STRINGS        |
+/// | bytes 0-3 | bytes 3-6 | bytes 7-10 | bytes 11-14 | bytes 15-17 |
+/// |     11    |    15     |     18     |     abc\0   |      de\0   |
+/// |----------------------------------------------------------------|
+/// \param[in] items elements of the tensor
+/// \param[in] shape shape of the output tensor
+/// \param[out] out output argument to hold the created Tensor
+/// \return Status Code
+template <>
+inline Status Tensor::CreateFromVector<std::string>(const std::vector<std::string> &items, const TensorShape &shape,
+                                                    TensorPtr *out) {
+  CHECK_FAIL_RETURN_UNEXPECTED(
+    items.size() == shape.NumOfElements(),
+    "Number of elements in the vector does not match the number of elements of the shape required");
+  const TensorAlloc *alloc = GlobalContext::Instance()->tensor_allocator();
+  *out = std::allocate_shared<Tensor>(*alloc, TensorShape({static_cast<dsize_t>(items.size())}),
+                                      DataType(DataType::DE_STRING));
+  if (items.size() == 0) {
+    if (shape.known()) {
+      return (*out)->Reshape(shape);
+    }
+  }
+  auto length_sum = [](dsize_t sum, const std::string &s) { return s.length() + sum; };
+  dsize_t total_length = std::accumulate(items.begin(), items.end(), 0, length_sum);
+
+  // total bytes needed = offset array + strings
+  // offset array needs to store one offset var per element + 1 extra to get the length of the last string.
+  // strings will be null-terminated --> need 1 extra byte per element
+  dsize_t num_bytes = (kOffsetSize + 1) * (*out)->shape_.NumOfElements() + kOffsetSize + total_length;
+
+  (*out)->AllocateBuffer(num_bytes);
+  auto offset_arr = reinterpret_cast<offset_t *>((*out)->data_);
+  uchar *buf = (*out)->GetStringsBuffer();
+
+  offset_t offset = buf - (*out)->data_;  // the first string will start here
+  uint32_t i = 0;
+  for (const auto &str : items) {
+    //  insert the start index of the string.
+    offset_arr[i++] = offset;
+    // total bytes are reduced by kOffsetSize
+    num_bytes -= kOffsetSize;
+    // insert actual string
+    int ret_code = memcpy_s((*out)->data_ + offset, num_bytes, common::SafeCStr(str), str.length() + 1);
+    if (ret_code != 0) MS_LOG(ERROR) << "Cannot copy string into Tensor";
+    //  next string will be stored right after the current one.
+    offset = offset + str.length() + 1;
+    // total bytes are reduced by the length of the string
+    num_bytes -= str.length() + 1;
+  }
+  // store one more offset value so we can get the length of the last string
+  // length[last_element] = offset_arr[last_element + 1] - offset_arr[last_element]
+  offset_arr[i] = offset;
+
+  (*out)->data_end_ = (*out)->data_ + offset_arr[i];
+
+  MS_ASSERT(num_bytes == 0);
+  if (shape.known()) {
+    RETURN_IF_NOT_OK((*out)->Reshape(shape));
+  }
+  return Status::OK();
+}
+/// Create a string scalar Tensor from the given value.
+/// \param[in] item value
+/// \param[out] out Created tensor
+/// \return Status code
+template <>
+inline Status Tensor::CreateScalar<std::string>(const std::string &item, TensorPtr *out) {
+  return CreateFromVector<std::string>({item}, TensorShape::CreateScalar(), out);
+}
 }  // namespace dataset
 }  // namespace mindspore
 #endif  // MINDSPORE_CCSRC_MINDDATA_DATASET_CORE_TENSOR_H_

mindspore/ccsrc/minddata/dataset/kernels/data/data_utils.cc

@@ -97,7 +97,7 @@ Status OneHotEncoding(std::shared_ptr<Tensor> input, std::shared_ptr<Tensor> *ou
     if (input->Rank() == 1) num_elements = input->shape()[0];
     TensorShape out_shape({num_elements, num_classes});
     std::shared_ptr<Tensor> out;
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, TensorImpl::kFlexible, out_shape, input->type()));
+    RETURN_IF_NOT_OK(Tensor::CreateEmpty(out_shape, input->type(), &out));
     RETURN_IF_NOT_OK(out->Zero());
     for (dsize_t i = 0; i < num_elements; ++i) {
       if (input->type().IsUnsignedInt()) {
@@ -133,7 +133,9 @@ Status Fill(const std::shared_ptr<Tensor> input, std::shared_ptr<Tensor> *output
     fill_output = fill_value;
   }
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, TensorImpl::kFlexible, input_shape, input_type));
+  if (input_type.IsNumeric()) {
+    RETURN_IF_NOT_OK(Tensor::CreateEmpty(input_shape, input_type, &out));
+  }
 
   switch (input_type.value()) {
     case DataType::DE_BOOL: {
@@ -216,7 +218,7 @@ Status Fill(const std::shared_ptr<Tensor> input, std::shared_ptr<Tensor> *output
       for (int i = 0; i < input_shape.NumOfElements(); i++) {
         strings.emplace_back(fill_string);
       }
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, strings, input_shape));
+      RETURN_IF_NOT_OK(Tensor::CreateFromVector(strings, input_shape, &out));
       break;
     }
     case DataType::DE_UNKNOWN: {
@@ -285,9 +287,8 @@ void CastFrom(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *out
 
 // Type cast operator
 Status TypeCast(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *output, const DataType &data_type) {
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(output, TensorImpl::kFlexible, input->shape(), data_type));
+  RETURN_IF_NOT_OK(Tensor::CreateEmpty(input->shape(), data_type, output));
 
-  RETURN_IF_NOT_OK((*output)->AllocateBuffer((*output)->SizeInBytes()));
   switch (input->type().value()) {
     case DataType::DE_BOOL:
       CastFrom<bool>(input, output);
@@ -335,8 +336,7 @@ Status TypeCast(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *o
 Status ToFloat16(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *output) {
   // initiate new tensor for type cast
   DataType new_type = DataType("float16");
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(output, TensorImpl::kFlexible, input->shape(), new_type));
+  RETURN_IF_NOT_OK(Tensor::CreateEmpty(input->shape(), new_type, output));
-  RETURN_IF_NOT_OK((*output)->AllocateBuffer((*output)->SizeInBytes()));
 
   auto in_itr = input->begin<float>();
   auto out_itr = (*output)->begin<float16>();
@@ -387,7 +387,7 @@ Status PadEndNumeric(const std::shared_ptr<Tensor> &src, std::shared_ptr<Tensor>
     (*dst) = src;  // if no padding, copy the pointer
   } else {
     CHECK_FAIL_RETURN_UNEXPECTED(src->Rank() == pad_shape.size(), "Pad to diff rank not allowed");
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(dst, TensorImpl::kFlexible, TensorShape(pad_shape), src->type()));
+    RETURN_IF_NOT_OK(Tensor::CreateEmpty(TensorShape(pad_shape), src->type(), dst));
     auto tensor_type = src->type().value();
     if (pad_val == 0) {  // if pad with zero, don't care what type it is
       RETURN_IF_NOT_OK((*dst)->Zero());
@@ -447,7 +447,7 @@ Status PadEndString(const std::shared_ptr<Tensor> &src, std::shared_ptr<Tensor>
     std::vector<dsize_t> cur_ind(src->Rank(), 0);
     std::vector<std::string> strings;
     RETURN_IF_NOT_OK(PadEndStringHelper(src, &strings, TensorShape(pad_shape), cur_ind, 0, pad_val));
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(dst, strings, TensorShape(pad_shape)));
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(strings, TensorShape(pad_shape), dst));
   }
   return Status::OK();
 }
@@ -521,7 +521,7 @@ Status Mask(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *outpu
                                "Cannot convert constant value to the type of the input tensor.");
   CHECK_FAIL_RETURN_UNEXPECTED(value->shape() == TensorShape::CreateScalar(), "Value is not a scalar");
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(output, TensorImpl::kFlexible, input->shape(), DataType(DataType::DE_BOOL)));
+  RETURN_IF_NOT_OK(Tensor::CreateEmpty(input->shape(), DataType(DataType::DE_BOOL), output));
 
   std::unique_ptr<TypeCastOp> value_cast_op(new TypeCastOp(input->type()));
   std::shared_ptr<Tensor> casted_value;
@@ -629,7 +629,7 @@ Status ConcatenateHelper(const std::shared_ptr<Tensor> &input, std::shared_ptr<T
   std::shared_ptr<Tensor> out;
 
   if (input->type().IsNumeric()) {
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, TensorImpl::kFlexible, t, input->type()));
+    RETURN_IF_NOT_OK(Tensor::CreateEmpty(t, input->type(), &out));
 
     RETURN_IF_NOT_OK(out->Concatenate({0}, input));
     RETURN_IF_NOT_OK(out->Concatenate({input->shape()[0]}, append));
@@ -645,7 +645,7 @@ Status ConcatenateHelper(const std::shared_ptr<Tensor> &input, std::shared_ptr<T
     for (; itr != append->end<std::string_view>(); itr++) {
       strings.emplace_back(*itr);
     }
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, strings, t));
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(strings, t, &out));
 
     *output = out;
   }

mindspore/ccsrc/minddata/dataset/kernels/data/duplicate_op.cc

@@ -26,7 +26,7 @@ Status DuplicateOp::Compute(const TensorRow &input, TensorRow *output) {
   IO_CHECK_VECTOR(input, output);
   CHECK_FAIL_RETURN_UNEXPECTED(input.size() == 1, "Input should be one tensor");
   std::shared_ptr<Tensor> out;
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, input[0]));
+  RETURN_IF_NOT_OK(Tensor::CreateFromTensor(input[0], &out));
   output->push_back(input[0]);
   output->push_back(out);
   return Status::OK();

mindspore/ccsrc/minddata/dataset/kernels/image/image_utils.cc

@@ -63,9 +63,8 @@ int GetCVBorderType(BorderType type) {
 Status Flip(std::shared_ptr<Tensor> input, std::shared_ptr<Tensor> *output, int flip_code) {
   std::shared_ptr<CVTensor> input_cv = CVTensor::AsCVTensor(std::move(input));
 
-  std::shared_ptr<CVTensor> output_cv = std::make_shared<CVTensor>(input_cv->shape(), input_cv->type());
+  std::shared_ptr<CVTensor> output_cv;
-  RETURN_UNEXPECTED_IF_NULL(output_cv);
+  RETURN_IF_NOT_OK(CVTensor::CreateEmpty(input_cv->shape(), input_cv->type(), &output_cv));
-  RETURN_IF_NOT_OK(output_cv->AllocateBuffer(output_cv->SizeInBytes()));
 
   if (input_cv->mat().data) {
     try {
@@ -110,8 +109,9 @@ Status Resize(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *out
     TensorShape shape{output_height, output_width};
     int num_channels = input_cv->shape()[2];
     if (input_cv->Rank() == 3) shape = shape.AppendDim(num_channels);
-    std::shared_ptr<CVTensor> output_cv = std::make_shared<CVTensor>(shape, input_cv->type());
+    std::shared_ptr<CVTensor> output_cv;
-    RETURN_UNEXPECTED_IF_NULL(output_cv);
+    RETURN_IF_NOT_OK(CVTensor::CreateEmpty(shape, input_cv->type(), &output_cv));
+
     auto cv_mode = GetCVInterpolationMode(mode);
     cv::resize(in_image, output_cv->mat(), cv::Size(output_width, output_height), fx, fy, cv_mode);
     *output = std::static_pointer_cast<Tensor>(output_cv);
@@ -147,8 +147,8 @@ Status DecodeCv(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *o
       RETURN_STATUS_UNEXPECTED(err);
     }
     cv::cvtColor(img_mat, img_mat, static_cast<int>(cv::COLOR_BGR2RGB));
-    std::shared_ptr<CVTensor> output_cv = std::make_shared<CVTensor>(img_mat);
+    std::shared_ptr<CVTensor> output_cv;
-    RETURN_UNEXPECTED_IF_NULL(output_cv);
+    RETURN_IF_NOT_OK(CVTensor::CreateFromMat(img_mat, &output_cv));
     *output = std::static_pointer_cast<Tensor>(output_cv);
     return Status::OK();
   } catch (const cv::Exception &e) {
@@ -309,7 +309,8 @@ Status JpegCropAndDecode(const std::shared_ptr<Tensor> &input, std::shared_ptr<T
   // three number of output components, always convert to RGB and output
   constexpr int kOutNumComponents = 3;
   TensorShape ts = TensorShape({crop_h, crop_w, kOutNumComponents});
-  auto output_tensor = std::make_shared<Tensor>(ts, DataType(DataType::DE_UINT8));
+  std::shared_ptr<Tensor> output_tensor;
+  RETURN_IF_NOT_OK(Tensor::CreateEmpty(ts, DataType(DataType::DE_UINT8), &output_tensor));
   const int buffer_size = output_tensor->SizeInBytes();
   JSAMPLE *buffer = reinterpret_cast<JSAMPLE *>(&(*output_tensor->begin<uint8_t>()));
   const int max_scanlines_to_read = skipped_scanlines + crop_h;
@@ -331,8 +332,8 @@ Status Rescale(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *ou
     RETURN_STATUS_UNEXPECTED("Could not convert to CV Tensor");
   }
   cv::Mat input_image = input_cv->mat();
-  std::shared_ptr<CVTensor> output_cv = std::make_shared<CVTensor>(input_cv->shape(), DataType(DataType::DE_FLOAT32));
+  std::shared_ptr<CVTensor> output_cv;
-  RETURN_UNEXPECTED_IF_NULL(output_cv);
+  RETURN_IF_NOT_OK(CVTensor::CreateEmpty(input_cv->shape(), DataType(DataType::DE_FLOAT32), &output_cv));
   try {
     input_image.convertTo(output_cv->mat(), CV_32F, rescale, shift);
     *output = std::static_pointer_cast<Tensor>(output_cv);
@@ -354,8 +355,8 @@ Status Crop(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *outpu
     TensorShape shape{h, w};
     int num_channels = input_cv->shape()[2];
     if (input_cv->Rank() == 3) shape = shape.AppendDim(num_channels);
-    std::shared_ptr<CVTensor> output_cv = std::make_shared<CVTensor>(shape, input_cv->type());
+    std::shared_ptr<CVTensor> output_cv;
-    RETURN_UNEXPECTED_IF_NULL(output_cv);
+    RETURN_IF_NOT_OK(CVTensor::CreateEmpty(shape, input_cv->type(), &output_cv));
     cv::Rect roi(x, y, w, h);
     (input_cv->mat())(roi).copyTo(output_cv->mat());
     *output = std::static_pointer_cast<Tensor>(output_cv);
@@ -386,10 +387,11 @@ Status HwcToChw(std::shared_ptr<Tensor> input, std::shared_ptr<Tensor> *output)
     int height = input_cv->shape()[0];
     int width = input_cv->shape()[1];
 
-    auto output_cv = std::make_unique<CVTensor>(TensorShape{num_channels, height, width}, input_cv->type());
+    std::shared_ptr<CVTensor> output_cv;
+    CVTensor::CreateEmpty(TensorShape{num_channels, height, width}, input_cv->type(), &output_cv);
     for (int i = 0; i < num_channels; ++i) {
       cv::Mat mat;
-      RETURN_IF_NOT_OK(output_cv->Mat({i}, &mat));
+      RETURN_IF_NOT_OK(output_cv->MatAtIndex({i}, &mat));
       cv::extractChannel(input_cv->mat(), mat, i);
     }
     *output = std::move(output_cv);
@@ -406,8 +408,9 @@ Status SwapRedAndBlue(std::shared_ptr<Tensor> input, std::shared_ptr<Tensor> *ou
     if (input_cv->shape().Size() != 3 || num_channels != 3) {
       RETURN_STATUS_UNEXPECTED("The shape is incorrect: number of channels does not equal 3");
     }
-    auto output_cv = std::make_shared<CVTensor>(input_cv->shape(), input_cv->type());
+    std::shared_ptr<CVTensor> output_cv;
-    RETURN_UNEXPECTED_IF_NULL(output_cv);
+    RETURN_IF_NOT_OK(CVTensor::CreateEmpty(input_cv->shape(), input_cv->type(), &output_cv));
+
     cv::cvtColor(input_cv->mat(), output_cv->mat(), static_cast<int>(cv::COLOR_BGR2RGB));
     *output = std::static_pointer_cast<Tensor>(output_cv);
     return Status::OK();
@@ -440,8 +443,8 @@ Status CropAndResize(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tenso
     TensorShape shape{target_height, target_width};
     int num_channels = input_cv->shape()[2];
     if (input_cv->Rank() == 3) shape = shape.AppendDim(num_channels);
-    std::shared_ptr<CVTensor> cvt_out = std::make_shared<CVTensor>(shape, input_cv->type());
+    std::shared_ptr<CVTensor> cvt_out;
-    RETURN_UNEXPECTED_IF_NULL(cvt_out);
+    RETURN_IF_NOT_OK(CVTensor::CreateEmpty(shape, input_cv->type(), &cvt_out));
     cv::resize(cv_in(roi), cvt_out->mat(), cv::Size(target_width, target_height), 0, 0, cv_mode);
     *output = std::static_pointer_cast<Tensor>(cvt_out);
     return Status::OK();
@@ -475,8 +478,7 @@ Status Rotate(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *out
     if (!expand) {
       // this case means that the shape doesn't change, size stays the same
       // We may not need this memcpy if it is in place.
-      output_cv = std::make_shared<CVTensor>(input_cv->shape(), input_cv->type());
+      RETURN_IF_NOT_OK(CVTensor::CreateEmpty(input_cv->shape(), input_cv->type(), &output_cv));
-      RETURN_UNEXPECTED_IF_NULL(output_cv);
       // using inter_nearest to comply with python default
       cv::warpAffine(input_img, output_cv->mat(), rot, input_img.size(), GetCVInterpolationMode(interpolation),
                      cv::BORDER_CONSTANT, fill_color);
@@ -489,7 +491,7 @@ Status Rotate(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *out
       // use memcpy and don't compute the new shape since openCV has a rounding problem
       cv::warpAffine(input_img, output_img, rot, bbox.size(), GetCVInterpolationMode(interpolation),
                      cv::BORDER_CONSTANT, fill_color);
-      output_cv = std::make_shared<CVTensor>(output_img);
+      RETURN_IF_NOT_OK(CVTensor::CreateFromMat(output_img, &output_cv));
       RETURN_UNEXPECTED_IF_NULL(output_cv);
     }
     *output = std::static_pointer_cast<Tensor>(output_cv);
@@ -506,8 +508,8 @@ Status Normalize(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *
     RETURN_STATUS_UNEXPECTED("Could not convert to CV Tensor");
   }
   cv::Mat in_image = input_cv->mat();
-  std::shared_ptr<CVTensor> output_cv = std::make_shared<CVTensor>(input_cv->shape(), DataType(DataType::DE_FLOAT32));
+  std::shared_ptr<CVTensor> output_cv;
-  RETURN_UNEXPECTED_IF_NULL(output_cv);
+  RETURN_IF_NOT_OK(CVTensor::CreateEmpty(input_cv->shape(), DataType(DataType::DE_FLOAT32), &output_cv));
   mean->Squeeze();
   if (mean->type() != DataType::DE_FLOAT32 || mean->Rank() != 1 || mean->shape()[0] != 3) {
     std::string err_msg = "Mean tensor should be of size 3 and type float.";
@@ -548,8 +550,8 @@ Status AdjustBrightness(const std::shared_ptr<Tensor> &input, std::shared_ptr<Te
     if (input_cv->Rank() != 3 || num_channels != 3) {
       RETURN_STATUS_UNEXPECTED("The shape is incorrect: number of channels does not equal 3");
     }
-    auto output_cv = std::make_shared<CVTensor>(input_cv->shape(), input_cv->type());
+    std::shared_ptr<CVTensor> output_cv;
-    RETURN_UNEXPECTED_IF_NULL(output_cv);
+    RETURN_IF_NOT_OK(CVTensor::CreateEmpty(input_cv->shape(), input_cv->type(), &output_cv));
     output_cv->mat() = input_img * alpha;
     *output = std::static_pointer_cast<Tensor>(output_cv);
   } catch (const cv::Exception &e) {
@@ -572,8 +574,8 @@ Status AdjustContrast(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tens
     cv::Mat gray, output_img;
     cv::cvtColor(input_img, gray, CV_RGB2GRAY);
     int mean_img = static_cast<int>(cv::mean(gray).val[0] + 0.5);
-    std::shared_ptr<CVTensor> output_cv = std::make_shared<CVTensor>(input_cv->shape(), input_cv->type());
+    std::shared_ptr<CVTensor> output_cv;
-    RETURN_UNEXPECTED_IF_NULL(output_cv);
+    RETURN_IF_NOT_OK(CVTensor::CreateEmpty(input_cv->shape(), input_cv->type(), &output_cv));
     output_img = cv::Mat::zeros(input_img.rows, input_img.cols, CV_8UC1);
     output_img = output_img + mean_img;
     cv::cvtColor(output_img, output_img, CV_GRAY2RGB);
@@ -680,7 +682,9 @@ Status AutoContrast(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor
     cv::Mat result;
     cv::merge(image_result, result);
     result.convertTo(result, input_cv->mat().type());
-    std::shared_ptr<CVTensor> output_cv = std::make_shared<CVTensor>(result);
+    std::shared_ptr<CVTensor> output_cv;
+    RETURN_IF_NOT_OK(CVTensor::CreateFromMat(result, &output_cv));
+    (*output) = std::static_pointer_cast<Tensor>(output_cv);
     (*output) = std::static_pointer_cast<Tensor>(output_cv);
     (*output)->Reshape(input->shape());
   } catch (const cv::Exception &e) {
@@ -700,8 +704,8 @@ Status AdjustSaturation(const std::shared_ptr<Tensor> &input, std::shared_ptr<Te
     if (input_cv->Rank() != 3 || num_channels != 3) {
       RETURN_STATUS_UNEXPECTED("The shape is incorrect: number of channels does not equal 3");
     }
-    auto output_cv = std::make_shared<CVTensor>(input_cv->shape(), input_cv->type());
+    std::shared_ptr<CVTensor> output_cv;
-    RETURN_UNEXPECTED_IF_NULL(output_cv);
+    RETURN_IF_NOT_OK(CVTensor::CreateEmpty(input_cv->shape(), input_cv->type(), &output_cv));
     cv::Mat output_img = output_cv->mat();
     cv::Mat gray;
     cv::cvtColor(input_img, gray, CV_RGB2GRAY);
@@ -729,8 +733,8 @@ Status AdjustHue(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *
     if (input_cv->Rank() != 3 || num_channels != 3) {
       RETURN_STATUS_UNEXPECTED("The shape is incorrect: number of channels does not equal 3");
     }
-    auto output_cv = std::make_shared<CVTensor>(input_cv->shape(), input_cv->type());
+    std::shared_ptr<CVTensor> output_cv;
-    RETURN_UNEXPECTED_IF_NULL(output_cv);
+    RETURN_IF_NOT_OK(CVTensor::CreateEmpty(input_cv->shape(), input_cv->type(), &output_cv));
     cv::Mat output_img;
     cv::cvtColor(input_img, output_img, CV_RGB2HSV_FULL);
     for (int y = 0; y < output_img.cols; y++) {
@@ -781,7 +785,8 @@ Status Equalize(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *o
     }
     cv::Mat result;
     cv::merge(image_result, result);
-    std::shared_ptr<CVTensor> output_cv = std::make_shared<CVTensor>(result);
+    std::shared_ptr<CVTensor> output_cv;
+    RETURN_IF_NOT_OK(CVTensor::CreateFromMat(result, &output_cv));
     (*output) = std::static_pointer_cast<Tensor>(output_cv);
     (*output)->Reshape(input->shape());
   } catch (const cv::Exception &e) {
@@ -867,8 +872,8 @@ Status Pad(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *output
     } else {
       cv::copyMakeBorder(input_cv->mat(), out_image, pad_top, pad_bottom, pad_left, pad_right, b_type);
     }
-    std::shared_ptr<CVTensor> output_cv = std::make_shared<CVTensor>(out_image);
+    std::shared_ptr<CVTensor> output_cv;
-    RETURN_UNEXPECTED_IF_NULL(output_cv);
+    RETURN_IF_NOT_OK(CVTensor::CreateFromMat(out_image, &output_cv));
     // pad the dimension if shape information is only 2 dimensional, this is grayscale
     int num_channels = input_cv->shape()[2];
     if (input_cv->Rank() == 3 && num_channels == 1 && output_cv->Rank() == 2) output_cv->ExpandDim(2);
@@ -932,7 +937,7 @@ Status UpdateBBoxesForCrop(std::shared_ptr<Tensor> *bboxList, size_t *bboxCount,
     }
   }
   std::shared_ptr<Tensor> retV;
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&retV, copyVals, TensorShape({static_cast<dsize_t>(*bboxCount), bboxDim})));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(copyVals, TensorShape({static_cast<dsize_t>(*bboxCount), bboxDim}), &retV));
   (*bboxList) = retV;  // reset pointer
   return Status::OK();
 }

mindspore/ccsrc/minddata/dataset/kernels/image/invert_op.cc

@@ -40,8 +40,8 @@ Status InvertOp::Compute(const std::shared_ptr<Tensor> &input, std::shared_ptr<T
     if (num_channels != 3) {
       RETURN_STATUS_UNEXPECTED("The shape is incorrect: num of channels != 3");
     }
-
+    std::shared_ptr<CVTensor> output_cv;
-    auto output_cv = std::make_shared<CVTensor>(input_cv->shape(), input_cv->type());
+    RETURN_IF_NOT_OK(CVTensor::CreateEmpty(input_cv->shape(), input_cv->type(), &output_cv));
     RETURN_UNEXPECTED_IF_NULL(output_cv);
 
     output_cv->mat() = cv::Scalar::all(255) - input_img;

mindspore/ccsrc/minddata/dataset/kernels/image/normalize_op.cc

@@ -24,20 +24,14 @@
 namespace mindspore {
 namespace dataset {
 NormalizeOp::NormalizeOp(float mean_r, float mean_g, float mean_b, float std_r, float std_g, float std_b) {
-  int size[] = {3};
+  Status s = Tensor::CreateFromVector<float>({mean_r, mean_g, mean_b}, &mean_);
-  cv::Mat mean_cv(1, size, CV_32F);
+  if (s.IsError()) {
-  mean_cv.at<float>(0) = mean_r;
+    MS_LOG(ERROR) << "Could not create mean tensor.";
-  mean_cv.at<float>(1) = mean_g;
+  }
-  mean_cv.at<float>(2) = mean_b;
+  s = Tensor::CreateFromVector<float>({std_r, std_g, std_b}, &std_);
-  mean_ = std::make_shared<CVTensor>(mean_cv);
+  if (s.IsError()) {
-  mean_->Squeeze();
+    MS_LOG(ERROR) << "Could not create std tensor.";
-
+  }
-  cv::Mat std_cv(1, size, CV_32F);
-  std_cv.at<float>(0) = std_r;
-  std_cv.at<float>(1) = std_g;
-  std_cv.at<float>(2) = std_b;
-  std_ = std::make_shared<CVTensor>(std_cv);
-  std_->Squeeze();
 }
 
 Status NormalizeOp::Compute(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *output) {
@@ -47,9 +41,7 @@ Status NormalizeOp::Compute(const std::shared_ptr<Tensor> &input, std::shared_pt
 }
 
 void NormalizeOp::Print(std::ostream &out) const {
-  out << "NormalizeOp, mean: " << mean_->mat().at<float>(0) << ", " << mean_->mat().at<float>(1) << ", "
+  out << "NormalizeOp, mean: " << mean_ << std::endl << "std: " << std_ << std::endl;
-      << mean_->mat().at<float>(2) << "std: " << std_->mat().at<float>(0) << ", " << std_->mat().at<float>(1) << ", "
-      << std_->mat().at<float>(2) << std::endl;
 }
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/kernels/image/normalize_op.h

@@ -39,8 +39,8 @@ class NormalizeOp : public TensorOp {
   std::string Name() const override { return kNormalizeOp; }
 
  private:
-  std::shared_ptr<CVTensor> mean_;
+  std::shared_ptr<Tensor> mean_;
-  std::shared_ptr<CVTensor> std_;
+  std::shared_ptr<Tensor> std_;
 };
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/kernels/py_func_op.cc

@@ -49,7 +49,7 @@ Status PyFuncOp::Compute(const TensorRow &input, TensorRow *output) {
       if (py::isinstance<py::array>(ret_py_obj)) {
         // In case of a n-1 mapping, the return value will be a numpy array
         std::shared_ptr<Tensor> out;
-        RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, ret_py_obj.cast<py::array>()));
+        RETURN_IF_NOT_OK(Tensor::CreateFromNpArray(ret_py_obj.cast<py::array>(), &out));
         output->push_back(out);
       } else if (py::isinstance<py::tuple>(ret_py_obj)) {
         // In case of a n-m mapping, the return value will be a tuple of numpy arrays
@@ -61,7 +61,7 @@ Status PyFuncOp::Compute(const TensorRow &input, TensorRow *output) {
             goto ShapeMisMatch;
           }
           std::shared_ptr<Tensor> out;
-          RETURN_IF_NOT_OK(Tensor::CreateTensor(&out, ret_py_ele.cast<py::array>()));
+          RETURN_IF_NOT_OK(Tensor::CreateFromNpArray(ret_py_ele.cast<py::array>(), &out));
           output->push_back(out);
         }
       } else {

mindspore/ccsrc/minddata/dataset/text/kernels/basic_tokenizer_op.cc

@@ -136,8 +136,7 @@ Status BasicTokenizerOp::CaseFoldWithoutUnusedWords(const std::shared_ptr<Tensor
   for (auto iter = input->begin<std::string_view>(); iter != input->end<std::string_view>(); iter++) {
     RETURN_IF_NOT_OK(CaseFoldWithoutUnusedWords(*iter, kUnusedWords, &strs[i++]));
   }
-  *output = std::make_shared<Tensor>(std::move(strs), input->shape());
+  return Tensor::CreateFromVector(strs, input->shape(), output);
-  return Status::OK();
 }
 
 Status BasicTokenizerOp::Compute(const TensorRow &input, TensorRow *output) {

mindspore/ccsrc/minddata/dataset/text/kernels/case_fold_op.cc

@@ -39,8 +39,7 @@ Status CaseFoldOp::Compute(const std::shared_ptr<Tensor> &input, std::shared_ptr
     nfkc_case_fold->normalizeUTF8(0, icu::StringPiece((*iter).data(), (*iter).size()), sink, nullptr, error);
     CHECK_FAIL_RETURN_UNEXPECTED(error.isSuccess(), "normalizeUTF8 failed.");
   }
-  *output = std::make_shared<Tensor>(std::move(strs), input->shape());
+  return Tensor::CreateFromVector(strs, input->shape(), output);
-  return Status::OK();
 }
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/text/kernels/data_utils.cc

@@ -33,12 +33,7 @@ Status SlidingWindowHelper(const std::shared_ptr<Tensor> &input, std::shared_ptr
   // if the data row has fewer items than width, the corresponding result row will be empty
   if (out_shape.Size() == 0) {
     MS_LOG(WARNING) << "The data row has fewer items than width, the result will be empty.";
-    if (input->type().value() == DataType::DE_STRING) {
+    return Tensor::CreateEmpty(TensorShape({0}), input->type(), output);
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(output, std::vector<std::string>{}, TensorShape({0})));
-    } else {
-      RETURN_IF_NOT_OK(Tensor::CreateTensor(output, TensorImpl::kFlexible, TensorShape({0}), input->type()));
-    }
-    return Status::OK();
   }
 
   axis = Tensor::HandleNeg(axis, input->shape().Size());

mindspore/ccsrc/minddata/dataset/text/kernels/jieba_tokenizer_op.cc

@@ -68,15 +68,12 @@ Status JiebaTokenizerOp::Compute(const TensorRow &input, TensorRow *output) {
       offsets_limit.push_back(static_cast<uint32_t>(item.offset + item.word.length()));
     }
   }
-  token_tensor = std::make_shared<Tensor>(words, TensorShape({(dsize_t)words.size()}));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(words, &token_tensor));
   output->push_back(token_tensor);
   if (with_offsets_) {
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_start_tensor, TensorImpl::kFlexible,
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_start, &offsets_start_tensor));
-                                          TensorShape({(dsize_t)offsets_start.size()}), DataType(DataType::DE_UINT32),
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_limit, &offsets_limit_tensor));
-                                          reinterpret_cast<unsigned char *>(&offsets_start[0])));
+
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_limit_tensor, TensorImpl::kFlexible,
-                                          TensorShape({(dsize_t)offsets_limit.size()}), DataType(DataType::DE_UINT32),
-                                          reinterpret_cast<unsigned char *>(&offsets_limit[0])));
     output->push_back(offsets_start_tensor);
     output->push_back(offsets_limit_tensor);
   }

mindspore/ccsrc/minddata/dataset/text/kernels/lookup_op.cc

@@ -36,9 +36,7 @@ Status LookupOp::Compute(const std::shared_ptr<Tensor> &input, std::shared_ptr<T
       word_ids.back() != Vocab::kNoTokenExists,
       "Lookup Error: token: " + std::string(*itr) + " doesn't exist in vocab and no unknown token is specified.");
   }
-
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(word_ids, input->shape(), output));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(output, TensorImpl::kFlexible, input->shape(), type_,
-                                        reinterpret_cast<unsigned char *>(word_ids.data())));
   return Status::OK();
 }
 Status LookupOp::OutputType(const std::vector<DataType> &inputs, std::vector<DataType> &outputs) {

mindspore/ccsrc/minddata/dataset/text/kernels/ngram_op.cc

@@ -67,7 +67,7 @@ Status NgramOp::Compute(const std::shared_ptr<Tensor> &input, std::shared_ptr<Te
       }
     }
   }
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(output, res, TensorShape({static_cast<dsize_t>(res.size())})));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(res, TensorShape({static_cast<dsize_t>(res.size())}), output));
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/text/kernels/normalize_utf8_op.cc

@@ -68,8 +68,7 @@ Status NormalizeUTF8Op::Compute(const std::shared_ptr<Tensor> &input, std::share
     normalize->normalizeUTF8(0, icu::StringPiece((*iter).data(), (*iter).size()), sink, nullptr, error);
     CHECK_FAIL_RETURN_UNEXPECTED(error.isSuccess(), "normalizeUTF8 failed.");
   }
-  *output = std::make_shared<Tensor>(std::move(strs), input->shape());
+  return Tensor::CreateFromVector(strs, input->shape(), output);
-  return Status::OK();
 }
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/text/kernels/regex_replace_op.cc

@@ -50,8 +50,7 @@ Status RegexReplaceOp::Compute(const std::shared_ptr<Tensor> &input, std::shared
   for (auto iter = input->begin<std::string_view>(); iter != input->end<std::string_view>(); iter++) {
     RETURN_IF_NOT_OK(RegexReplace(&matcher, *iter, &strs[i]));
   }
-  *output = std::make_shared<Tensor>(std::move(strs), input->shape());
+  return Tensor::CreateFromVector(strs, input->shape(), output);
-  return Status::OK();
 }
 }  // namespace dataset
 }  // namespace mindspore

mindspore/ccsrc/minddata/dataset/text/kernels/regex_tokenizer_op.cc

@@ -120,15 +120,11 @@ Status RegexTokenizerOp::Compute(const TensorRow &input, TensorRow *output) {
   std::shared_ptr<Tensor> token_tensor, offsets_start_tensor, offsets_limit_tensor;
   RETURN_IF_NOT_OK(input[0]->GetItemAt(&text, {}));
   RETURN_IF_NOT_OK(GetRegexTokens(std::string(text.data(), text.size()), &tokens, &offsets_start, &offsets_limit));
-  token_tensor = std::make_shared<Tensor>(std::move(tokens), TensorShape({(dsize_t)tokens.size()}));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(std::move(tokens), &token_tensor));
   output->push_back(token_tensor);
   if (with_offsets_) {
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_start_tensor, TensorImpl::kFlexible,
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_start, &offsets_start_tensor));
-                                          TensorShape({(dsize_t)offsets_start.size()}), DataType(DataType::DE_UINT32),
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_limit, &offsets_limit_tensor));
-                                          reinterpret_cast<unsigned char *>(&offsets_start[0])));
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_limit_tensor, TensorImpl::kFlexible,
-                                          TensorShape({(dsize_t)offsets_limit.size()}), DataType(DataType::DE_UINT32),
-                                          reinterpret_cast<unsigned char *>(&offsets_limit[0])));
     output->push_back(offsets_start_tensor);
     output->push_back(offsets_limit_tensor);
   }

mindspore/ccsrc/minddata/dataset/text/kernels/sentence_piece_tokenizer_op.cc

@@ -69,14 +69,14 @@ Status SentencePieceTokenizerOp::Compute(const std::shared_ptr<Tensor> &input, s
     if (!status.ok()) {
       RETURN_STATUS_UNEXPECTED("sentence piece tokenizer error");
     }
-    *output = std::make_unique<Tensor>(pieces, TensorShape({(dsize_t)pieces.size()}));
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(pieces, output));
   } else {
     std::vector<int> ids;
     auto status = processor_.Encode(sentence, &ids);
     if (!status.ok()) {
       RETURN_STATUS_UNEXPECTED("sentence piece tokenizer error");
     }
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(output, ids, TensorShape({(dsize_t)ids.size()})));
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(ids, output));
   }
   return Status::OK();
 }

mindspore/ccsrc/minddata/dataset/text/kernels/to_number_op.cc

@@ -114,7 +114,7 @@ Status ToNumberOp::ToSignedIntegral(const std::shared_ptr<Tensor> &input, std::s
     casted.push_back(casted_result);
   }
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(output, casted, input->shape()));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(casted, input->shape(), output));
   return Status::OK();
 }
 
@@ -157,7 +157,7 @@ Status ToNumberOp::ToUnsignedIntegral(const std::shared_ptr<Tensor> &input, std:
     casted.push_back(casted_result);
   }
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(output, casted, input->shape()));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(casted, input->shape(), output));
   return Status::OK();
 }
 
@@ -165,7 +165,7 @@ Status ToNumberOp::ToFloat16(const std::shared_ptr<Tensor> &input, std::shared_p
   // special case, float16 does not exist in c++, no native support for
   // casting, so cast to float first then use this method, which use Eigen.
   std::shared_ptr<Tensor> temp;
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(&temp, TensorImpl::kFlexible, input->shape(), DataType("float32")));
+  RETURN_IF_NOT_OK(Tensor::CreateEmpty(input->shape(), DataType("float32"), &temp));
   RETURN_IF_NOT_OK(ToFloat(input, &temp));
   RETURN_IF_NOT_OK(mindspore::dataset::ToFloat16(temp, output));
   return Status::OK();
@@ -200,7 +200,7 @@ Status ToNumberOp::ToFloat(const std::shared_ptr<Tensor> &input, std::shared_ptr
     casted.push_back(casted_result);
   }
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(output, casted, input->shape()));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(casted, input->shape(), output));
   return Status::OK();
 }
 
@@ -233,7 +233,7 @@ Status ToNumberOp::ToDouble(const std::shared_ptr<Tensor> &input, std::shared_pt
     casted.push_back(casted_result);
   }
 
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(output, casted, input->shape()));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(casted, input->shape(), output));
   return Status::OK();
 }
 

mindspore/ccsrc/minddata/dataset/text/kernels/unicode_char_tokenizer_op.cc

@@ -55,15 +55,13 @@ Status UnicodeCharTokenizerOp::Compute(const TensorRow &input, TensorRow *output
     offsets_start.push_back(0);
     offsets_limit.push_back(0);
   }
-  token_tensor = std::make_shared<Tensor>(splits, TensorShape({(dsize_t)splits.size()}));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(splits, &token_tensor));
+
   output->push_back(token_tensor);
   if (with_offsets_) {
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_start_tensor, TensorImpl::kFlexible,
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_start, &offsets_start_tensor));
-                                          TensorShape({(dsize_t)offsets_start.size()}), DataType(DataType::DE_UINT32),
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_limit, &offsets_limit_tensor));
-                                          reinterpret_cast<unsigned char *>(&offsets_start[0])));
+
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_limit_tensor, TensorImpl::kFlexible,
-                                          TensorShape({(dsize_t)offsets_limit.size()}), DataType(DataType::DE_UINT32),
-                                          reinterpret_cast<unsigned char *>(&offsets_limit[0])));
     output->push_back(offsets_start_tensor);
     output->push_back(offsets_limit_tensor);
   }

mindspore/ccsrc/minddata/dataset/text/kernels/unicode_script_tokenizer_op.cc

@@ -96,15 +96,12 @@ Status UnicodeScriptTokenizerOp::Compute(const TensorRow &input, TensorRow *outp
     offsets_start.push_back(0);
     offsets_limit.push_back(0);
   }
-  token_tensor = std::make_shared<Tensor>(splits, TensorShape({(dsize_t)splits.size()}));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(splits, &token_tensor));
   output->push_back(token_tensor);
   if (with_offsets_) {
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_start_tensor, TensorImpl::kFlexible,
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_start, &offsets_start_tensor));
-                                          TensorShape({(dsize_t)offsets_start.size()}), DataType(DataType::DE_UINT32),
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_limit, &offsets_limit_tensor));
-                                          reinterpret_cast<unsigned char *>(&offsets_start[0])));
+
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_limit_tensor, TensorImpl::kFlexible,
-                                          TensorShape({(dsize_t)offsets_limit.size()}), DataType(DataType::DE_UINT32),
-                                          reinterpret_cast<unsigned char *>(&offsets_limit[0])));
     output->push_back(offsets_start_tensor);
     output->push_back(offsets_limit_tensor);
   }

mindspore/ccsrc/minddata/dataset/text/kernels/whitespace_tokenizer_op.cc

@@ -79,15 +79,12 @@ Status WhitespaceTokenizerOp::Compute(const TensorRow &input, TensorRow *output)
     offsets_start.push_back(0);
     offsets_limit.push_back(0);
   }
-  token_tensor = std::make_shared<Tensor>(splits, TensorShape({(dsize_t)splits.size()}));
+  RETURN_IF_NOT_OK(Tensor::CreateFromVector(splits, &token_tensor));
   output->push_back(token_tensor);
   if (with_offsets_) {
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_start_tensor, TensorImpl::kFlexible,
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_start, &offsets_start_tensor));
-                                          TensorShape({(dsize_t)offsets_start.size()}), DataType(DataType::DE_UINT32),
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_limit, &offsets_limit_tensor));
-                                          reinterpret_cast<unsigned char *>(&offsets_start[0])));
+
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_limit_tensor, TensorImpl::kFlexible,
-                                          TensorShape({(dsize_t)offsets_limit.size()}), DataType(DataType::DE_UINT32),
-                                          reinterpret_cast<unsigned char *>(&offsets_limit[0])));
     output->push_back(offsets_start_tensor);
     output->push_back(offsets_limit_tensor);
   }

mindspore/ccsrc/minddata/dataset/text/kernels/wordpiece_tokenizer_op.cc

@@ -1,157 +1,154 @@
-/**
+/**
- * Copyright 2020 Huawei Technologies Co., Ltd
+ * Copyright 2020 Huawei Technologies Co., Ltd
- *
+ *
- * Licensed under the Apache License, Version 2.0 (the "License");
+ * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
+ * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ * You may obtain a copy of the License at
- *
+ *
- * http://www.apache.org/licenses/LICENSE-2.0
+ * http://www.apache.org/licenses/LICENSE-2.0
- *
+ *
- * Unless required by applicable law or agreed to in writing, software
+ * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
+ * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
+ * See the License for the specific language governing permissions and
- * limitations under the License.
+ * limitations under the License.
- */
+ */
-
+
-#include "minddata/dataset/text/kernels/wordpiece_tokenizer_op.h"
+#include "minddata/dataset/text/kernels/wordpiece_tokenizer_op.h"
-#include <algorithm>
+#include <algorithm>
-#include <utility>
+#include <utility>
-
+
-namespace mindspore {
+namespace mindspore {
-namespace dataset {
+namespace dataset {
-
+
-const char WordpieceTokenizerOp::kDefSuffixIndicator[] = "##";
+const char WordpieceTokenizerOp::kDefSuffixIndicator[] = "##";
-const int WordpieceTokenizerOp::kDefMaxBytesPerToken = 100;
+const int WordpieceTokenizerOp::kDefMaxBytesPerToken = 100;
-const char WordpieceTokenizerOp::kDefUnknownToken[] = "[UNK]";
+const char WordpieceTokenizerOp::kDefUnknownToken[] = "[UNK]";
-const bool WordpieceTokenizerOp::kDefWithOffsets = false;
+const bool WordpieceTokenizerOp::kDefWithOffsets = false;
-
+
-WordpieceTokenizerOp::WordpieceTokenizerOp(const std::shared_ptr<Vocab> &vocab, const std::string &suffix_indicator,
+WordpieceTokenizerOp::WordpieceTokenizerOp(const std::shared_ptr<Vocab> &vocab, const std::string &suffix_indicator,
-                                           const int &max_bytes_per_token, const std::string &unknown_token,
+                                           const int &max_bytes_per_token, const std::string &unknown_token,
-                                           const bool &with_offsets)
+                                           const bool &with_offsets)
-    : vocab_(vocab),
+    : vocab_(vocab),
-      suffix_indicator_(suffix_indicator),
+      suffix_indicator_(suffix_indicator),
-      max_bytes_per_token_(max_bytes_per_token),
+      max_bytes_per_token_(max_bytes_per_token),
-      unknown_token_(unknown_token),
+      unknown_token_(unknown_token),
-      with_offsets_(with_offsets) {}
+      with_offsets_(with_offsets) {}
-
+
-Status WordpieceTokenizerOp::LookupWord(const std::string &input_token, const RuneStrArray &runes, const int start,
+Status WordpieceTokenizerOp::LookupWord(const std::string &input_token, const RuneStrArray &runes, const int start,
-                                        bool *out_found, int *out_end) const {
+                                        bool *out_found, int *out_end) const {
-  CHECK_FAIL_RETURN_UNEXPECTED(start >= 0 && start < input_token.size(), "Out of range");
+  CHECK_FAIL_RETURN_UNEXPECTED(start >= 0 && start < input_token.size(), "Out of range");
-  *out_found = false;
+  *out_found = false;
-  for (int i = runes.size() - 1; i >= 0; i--) {
+  for (int i = runes.size() - 1; i >= 0; i--) {
-    *out_end = runes[i].offset + runes[i].len;
+    *out_end = runes[i].offset + runes[i].len;
-    int len = *out_end - start;
+    int len = *out_end - start;
-    std::string word = input_token.substr(start, len);
+    std::string word = input_token.substr(start, len);
-    if (start > 0) {
+    if (start > 0) {
-      word = suffix_indicator_ + word;
+      word = suffix_indicator_ + word;
-    }
+    }
-    if (vocab_->Lookup(word) != Vocab::kNoTokenExists) {
+    if (vocab_->Lookup(word) != Vocab::kNoTokenExists) {
-      *out_found = true;
+      *out_found = true;
-      break;
+      break;
-    }
+    }
-  }
+  }
-  return Status::OK();
+  return Status::OK();
-}
+}
-
+
-Status WordpieceTokenizerOp::FoundNoToken(const std::string &input_token, const uint32_t &basic_start,
+Status WordpieceTokenizerOp::FoundNoToken(const std::string &input_token, const uint32_t &basic_start,
-                                          std::vector<std::string> *out_tokens, std::vector<uint32_t> *offsets_start,
+                                          std::vector<std::string> *out_tokens, std::vector<uint32_t> *offsets_start,
-                                          std::vector<uint32_t> *offsets_limit) const {
+                                          std::vector<uint32_t> *offsets_limit) const {
-  out_tokens->clear();
+  out_tokens->clear();
-  offsets_start->push_back(basic_start);
+  offsets_start->push_back(basic_start);
-  if (unknown_token_.empty()) {
+  if (unknown_token_.empty()) {
-    out_tokens->emplace_back(input_token);
+    out_tokens->emplace_back(input_token);
-    offsets_limit->push_back(basic_start + input_token.length());
+    offsets_limit->push_back(basic_start + input_token.length());
-  } else {
+  } else {
-    out_tokens->emplace_back(unknown_token_);
+    out_tokens->emplace_back(unknown_token_);
-    offsets_limit->push_back(basic_start + input_token.length());
+    offsets_limit->push_back(basic_start + input_token.length());
-  }
+  }
-  return Status::OK();
+  return Status::OK();
-}
+}
-
+
-Status WordpieceTokenizerOp::AddSubword(const std::string &input_token, const int &start, const int &end,
+Status WordpieceTokenizerOp::AddSubword(const std::string &input_token, const int &start, const int &end,
-                                        std::vector<std::string> *out_tokens) const {
+                                        std::vector<std::string> *out_tokens) const {
-  CHECK_FAIL_RETURN_UNEXPECTED(start >= 0 && end > start && end <= input_token.size(), "Out of range");
+  CHECK_FAIL_RETURN_UNEXPECTED(start >= 0 && end > start && end <= input_token.size(), "Out of range");
-  std::string subword = input_token.substr(start, end - start);
+  std::string subword = input_token.substr(start, end - start);
-  if (start > 0) {
+  if (start > 0) {
-    subword = suffix_indicator_ + subword;
+    subword = suffix_indicator_ + subword;
-  }
+  }
-  out_tokens->emplace_back(subword);
+  out_tokens->emplace_back(subword);
-  return Status::OK();
+  return Status::OK();
-}
+}
-
+
-Status WordpieceTokenizerOp::GetTokens(const std::string &input_token, const uint32_t &basic_start,
+Status WordpieceTokenizerOp::GetTokens(const std::string &input_token, const uint32_t &basic_start,
-                                       std::vector<std::string> *out_tokens, std::vector<uint32_t> *offsets_start,
+                                       std::vector<std::string> *out_tokens, std::vector<uint32_t> *offsets_start,
-                                       std::vector<uint32_t> *offsets_limit) const {
+                                       std::vector<uint32_t> *offsets_limit) const {
-  if (input_token.size() > max_bytes_per_token_) {
+  if (input_token.size() > max_bytes_per_token_) {
-    offsets_start->push_back(basic_start);
+    offsets_start->push_back(basic_start);
-    if (!unknown_token_.empty()) {
+    if (!unknown_token_.empty()) {
-      offsets_limit->push_back(basic_start + unknown_token_.size());
+      offsets_limit->push_back(basic_start + unknown_token_.size());
-      out_tokens->emplace_back(unknown_token_);
+      out_tokens->emplace_back(unknown_token_);
-    } else {
+    } else {
-      out_tokens->emplace_back(input_token);
+      out_tokens->emplace_back(input_token);
-      offsets_limit->push_back(basic_start + input_token.size());
+      offsets_limit->push_back(basic_start + input_token.size());
-    }
+    }
-    return Status::OK();
+    return Status::OK();
-  }
+  }
-  RuneStrArray runes;
+  RuneStrArray runes;
-  if (!DecodeRunesInString(input_token.data(), input_token.size(), runes)) {
+  if (!DecodeRunesInString(input_token.data(), input_token.size(), runes)) {
-    RETURN_STATUS_UNEXPECTED("Decode utf8 string failed.");
+    RETURN_STATUS_UNEXPECTED("Decode utf8 string failed.");
-  }
+  }
-  int end = 0;
+  int end = 0;
-  for (int start = 0; start < input_token.size();) {
+  for (int start = 0; start < input_token.size();) {
-    bool found = false;
+    bool found = false;
-    RETURN_IF_NOT_OK(LookupWord(input_token, runes, start, &found, &end));
+    RETURN_IF_NOT_OK(LookupWord(input_token, runes, start, &found, &end));
-    if (found) {
+    if (found) {
-      RETURN_IF_NOT_OK(AddSubword(input_token, start, end, out_tokens));
+      RETURN_IF_NOT_OK(AddSubword(input_token, start, end, out_tokens));
-      offsets_start->push_back(static_cast<uint32_t>(basic_start + start));
+      offsets_start->push_back(static_cast<uint32_t>(basic_start + start));
-      offsets_limit->push_back(static_cast<uint32_t>(basic_start + end));
+      offsets_limit->push_back(static_cast<uint32_t>(basic_start + end));
-      start = end;
+      start = end;
-    } else {
+    } else {
-      return FoundNoToken(input_token, basic_start, out_tokens, offsets_start, offsets_limit);
+      return FoundNoToken(input_token, basic_start, out_tokens, offsets_start, offsets_limit);
-    }
+    }
-  }
+  }
-  return Status::OK();
+  return Status::OK();
-}
+}
-
+
-Status WordpieceTokenizerOp::Compute(const TensorRow &input, TensorRow *output) {
+Status WordpieceTokenizerOp::Compute(const TensorRow &input, TensorRow *output) {
-  IO_CHECK_VECTOR(input, output);
+  IO_CHECK_VECTOR(input, output);
-  if (input[0]->Rank() > 1 || input[0]->type() != DataType::DE_STRING) {
+  if (input[0]->Rank() > 1 || input[0]->type() != DataType::DE_STRING) {
-    RETURN_STATUS_UNEXPECTED("The input tensor should be scalar or 1-D string tensor");
+    RETURN_STATUS_UNEXPECTED("The input tensor should be scalar or 1-D string tensor");
-  }
+  }
-  dsize_t count = 0;
+  dsize_t count = 0;
-  std::vector<std::string> out_tokens;
+  std::vector<std::string> out_tokens;
-  std::vector<uint32_t> offsets_start, offsets_limit;
+  std::vector<uint32_t> offsets_start, offsets_limit;
-  std::shared_ptr<Tensor> token_tensor, offsets_start_tensor, offsets_limit_tensor;
+  std::shared_ptr<Tensor> token_tensor, offsets_start_tensor, offsets_limit_tensor;
-  for (auto iter = input[0]->begin<std::string_view>(); iter != input[0]->end<std::string_view>(); iter++) {
+  for (auto iter = input[0]->begin<std::string_view>(); iter != input[0]->end<std::string_view>(); iter++) {
-    uint32_t basic_start = 0;
+    uint32_t basic_start = 0;
-    std::vector<std::string> temp_tokens;
+    std::vector<std::string> temp_tokens;
-    if (with_offsets_ && input.size() == 3) {
+    if (with_offsets_ && input.size() == 3) {
-      RETURN_IF_NOT_OK(input[1]->GetItemAt<uint32_t>(&basic_start, {count, 0}));
+      RETURN_IF_NOT_OK(input[1]->GetItemAt<uint32_t>(&basic_start, {count, 0}));
-    }
+    }
-    RETURN_IF_NOT_OK(GetTokens(std::string(*iter), basic_start, &temp_tokens, &offsets_start, &offsets_limit));
+    RETURN_IF_NOT_OK(GetTokens(std::string(*iter), basic_start, &temp_tokens, &offsets_start, &offsets_limit));
-    out_tokens.insert(out_tokens.end(), temp_tokens.begin(), temp_tokens.end());
+    out_tokens.insert(out_tokens.end(), temp_tokens.begin(), temp_tokens.end());
-    count++;
+    count++;
-  }
+  }
-  if (out_tokens.empty()) {
+  if (out_tokens.empty()) {
-    out_tokens.emplace_back("");
+    out_tokens.emplace_back("");
-    offsets_start.push_back(0);
+    offsets_start.push_back(0);
-    offsets_limit.push_back(0);
+    offsets_limit.push_back(0);
-  }
+  }
-  token_tensor = std::make_shared<Tensor>(out_tokens, TensorShape({(dsize_t)out_tokens.size()}));
+  Tensor::CreateFromVector(out_tokens, &token_tensor);
-  output->push_back(token_tensor);
+  output->push_back(token_tensor);
-  if (with_offsets_) {
+  if (with_offsets_) {
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_start_tensor, TensorImpl::kFlexible,
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_start, &offsets_start_tensor));
-                                          TensorShape({(dsize_t)offsets_start.size()}), DataType(DataType::DE_UINT32),
+    RETURN_IF_NOT_OK(Tensor::CreateFromVector(offsets_limit, &offsets_limit_tensor));
-                                          reinterpret_cast<unsigned char *>(&offsets_start[0])));
+
-    RETURN_IF_NOT_OK(Tensor::CreateTensor(&offsets_limit_tensor, TensorImpl::kFlexible,
+    output->push_back(offsets_start_tensor);
-                                          TensorShape({(dsize_t)offsets_limit.size()}), DataType(DataType::DE_UINT32),
+    output->push_back(offsets_limit_tensor);
-                                          reinterpret_cast<unsigned char *>(&offsets_limit[0])));
+  }
-    output->push_back(offsets_start_tensor);
+  return Status::OK();
-    output->push_back(offsets_limit_tensor);
+}
-  }
+
-  return Status::OK();
+}  // namespace dataset
-}
+}  // namespace mindspore
-
-}  // namespace dataset
-}  // namespace mindspore

tests/ut/cpp/dataset/batch_op_test.cc

@@ -90,8 +90,8 @@ TEST_F(MindDataTestBatchOp, TestSimpleBatch) {
     rc = di.GetNextAsMap(&tensor_map);
     EXPECT_TRUE(rc.IsOk());
     std::shared_ptr<de::Tensor> t;
-    rc = de::Tensor::CreateTensor(&t, TensorImpl::kFlexible, de::TensorShape({12, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({12, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)payload);
+                                      (unsigned char *)payload, &t);
     EXPECT_TRUE(rc.IsOk());
     // verify the actual data in Tensor is correct
     EXPECT_EQ(*t == *tensor_map["col_sint64"], true);
@@ -119,14 +119,14 @@ TEST_F(MindDataTestBatchOp, TestRepeatBatchDropTrue) {
                          -9223372036854775807 - 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9223372036854775807};
     de::DatasetIterator di(tree);
     std::shared_ptr<de::Tensor> t1, t2, t3;
-    rc = de::Tensor::CreateTensor(&t1, TensorImpl::kFlexible, de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)payload);
+                                      (unsigned char *)payload, &t1);
     EXPECT_TRUE(rc.IsOk());
-    rc = de::Tensor::CreateTensor(&t2, TensorImpl::kFlexible, de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)(payload + 7));
+                                      (unsigned char *)(payload + 7), &t2);
     EXPECT_TRUE(rc.IsOk());
-    rc = de::Tensor::CreateTensor(&t3, TensorImpl::kFlexible, de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)(payload + 2));
+                                      (unsigned char *)(payload + 2), &t3);
     EXPECT_TRUE(rc.IsOk());
 
     TensorMap tensor_map;
@@ -164,17 +164,17 @@ TEST_F(MindDataTestBatchOp, TestRepeatBatchDropFalse) {
                          -9223372036854775807 - 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9223372036854775807};
     de::DatasetIterator di(tree);
     std::shared_ptr<de::Tensor> t1, t2, t3, t4;
-    rc = de::Tensor::CreateTensor(&t1, TensorImpl::kFlexible, de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)payload);
+                                      (unsigned char *)payload, &t1);
     EXPECT_TRUE(rc.IsOk());
-    rc = de::Tensor::CreateTensor(&t2, TensorImpl::kFlexible, de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)(payload + 7));
+                                      (unsigned char *)(payload + 7), &t2);
     EXPECT_TRUE(rc.IsOk());
-    rc = de::Tensor::CreateTensor(&t3, TensorImpl::kFlexible, de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)(payload + 2));
+                                      (unsigned char *)(payload + 2), &t3);
     EXPECT_TRUE(rc.IsOk());
-    rc = de::Tensor::CreateTensor(&t4, TensorImpl::kFlexible, de::TensorShape({3, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({3, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)(payload + 9));
+                                      (unsigned char *)(payload + 9), &t4);
     EXPECT_TRUE(rc.IsOk());
 
     TensorMap tensor_map;
@@ -216,11 +216,11 @@ TEST_F(MindDataTestBatchOp, TestBatchDropFalseRepeat) {
                          -9223372036854775807 - 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9223372036854775807};
     de::DatasetIterator di(tree);
     std::shared_ptr<de::Tensor> t1, t2;
-    rc = de::Tensor::CreateTensor(&t1, TensorImpl::kFlexible, de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({7, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)payload);
+                                      (unsigned char *)payload, &t1);
     EXPECT_TRUE(rc.IsOk());
-    rc = de::Tensor::CreateTensor(&t2, TensorImpl::kFlexible, de::TensorShape({5, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({5, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)(payload + 7));
+                                      (unsigned char *)(payload + 7), &t2);
     EXPECT_TRUE(rc.IsOk());
 
     TensorMap tensor_map;
@@ -262,11 +262,11 @@ TEST_F(MindDataTestBatchOp, TestBatchDropTrueRepeat) {
                          -9223372036854775807 - 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9223372036854775807};
     de::DatasetIterator di(tree);
     std::shared_ptr<de::Tensor> t1, t2;
-    rc = de::Tensor::CreateTensor(&t1, TensorImpl::kFlexible, de::TensorShape({5, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({5, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)payload);
+                                      (unsigned char *)payload, &t1);
     EXPECT_TRUE(rc.IsOk());
-    rc = de::Tensor::CreateTensor(&t2, TensorImpl::kFlexible, de::TensorShape({5, 1}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({5, 1}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)(payload + 5));
+                                      (unsigned char *)(payload + 5), &t2);
     EXPECT_TRUE(rc.IsOk());
 
     TensorMap tensor_map;
@@ -300,7 +300,7 @@ TEST_F(MindDataTestBatchOp, TestSimpleBatchPadding) {
   std::shared_ptr<BatchOp> op;
   PadInfo m;
   std::shared_ptr<Tensor> pad_value;
-  Tensor::CreateTensor(&pad_value, TensorImpl::kFlexible, TensorShape::CreateScalar(), DataType(DataType::DE_FLOAT32));
+  Tensor::CreateEmpty(TensorShape::CreateScalar(), DataType(DataType::DE_FLOAT32), &pad_value);
   pad_value->SetItemAt<float>({}, -1);
   m.insert({"col_1d", std::make_pair(TensorShape({4}), pad_value)});
   de::BatchOp::Builder(12).SetDrop(false).SetPaddingMap(m, true).Build(&op);
@@ -359,8 +359,8 @@ TEST_F(MindDataTestBatchOp, TestSimpleBatchPadding) {
                          -1,
                          -1};
     std::shared_ptr<de::Tensor> t;
-    rc = de::Tensor::CreateTensor(&t, TensorImpl::kFlexible, de::TensorShape({12, 4}), de::DataType(DataType::DE_INT64),
+    rc = de::Tensor::CreateFromMemory(de::TensorShape({12, 4}), de::DataType(DataType::DE_INT64),
-                                  (unsigned char *)payload);
+                                      (unsigned char *)payload, &t);
     de::DatasetIterator di(tree);
     TensorMap tensor_map;
     rc = di.GetNextAsMap(&tensor_map);

tests/ut/cpp/dataset/cache_op_test.cc

@@ -75,7 +75,8 @@ TEST_F(MindDataTestCacheOp, TestCacheServer) {
   EXPECT_TRUE(rc.IsOk());
 
   // Create a tensor, take a snapshot and restore it back, and compare.
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({2, 3}), DataType(DataType::DE_UINT64));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({2, 3}), DataType(DataType::DE_UINT64), &t);
   t->SetItemAt<uint64_t>({0, 0}, 1);
   t->SetItemAt<uint64_t>({0, 1}, 2);
   t->SetItemAt<uint64_t>({0, 2}, 3);
@@ -129,7 +130,8 @@ TEST_F(MindDataTestCacheOp, TestConcurrencyRequest) {
   rc = myClient.CreateCache(1, true);
   EXPECT_TRUE(rc.IsOk());
   std::cout << myClient << std::endl;
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({2, 3}), DataType(DataType::DE_UINT64));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({2, 3}), DataType(DataType::DE_UINT64), &t);
   t->SetItemAt<uint64_t>({0, 0}, 1);
   t->SetItemAt<uint64_t>({0, 1}, 2);
   t->SetItemAt<uint64_t>({0, 2}, 3);
@@ -403,11 +405,7 @@ TEST_F(MindDataTestCacheOp, TestImageFolderCacheMerge) {
   // replace it with the required tree structures for cache lookup op and cache merge op.
 
   std::shared_ptr<CacheOp> myCacheOp;
-  rc = CacheOp::Builder()
+  rc = CacheOp::Builder().SetNumWorkers(4).SetClient(myClient).SetRowsPerBuffer(3).Build(&myCacheOp);
-         .SetNumWorkers(4)
-         .SetClient(myClient)
-         .SetRowsPerBuffer(3)
-         .Build(&myCacheOp);
 
   std::shared_ptr<ImageFolderOp> so;
   ImageFolderOp::Builder builder;

tests/ut/cpp/dataset/channel_swap_test.cc

@@ -36,7 +36,7 @@ TEST_F(MindDataTestChannelSwap, TestOp) {
   int size_buffer = s[0] * s[1] * s[2];
 
   std::unique_ptr<uchar[]> output_buffer(new uchar[size_buffer]);
-  std::shared_ptr<Tensor> output_tensor(new Tensor(s, DataType(DataType::DE_UINT8)));
+  std::shared_ptr<Tensor> output_tensor;
 
   // Decoding
   std::unique_ptr<HwcToChwOp> op(new HwcToChwOp());

tests/ut/cpp/dataset/common/bboxop_common.cc

@@ -163,8 +163,11 @@ void BBoxOpCommon::CompareActualAndExpected(const std::string &op_name) {
     // after comparison is done remove temporary file
     EXPECT_TRUE(remove(actual_path.c_str()) == 0);
     // compare using ==operator by Tensor
+    std::shared_ptr<CVTensor> expect_img_t, actual_img_t;
+    CVTensor::CreateFromMat(expect_img, &expect_img_t);
+    CVTensor::CreateFromMat(actual_img, &actual_img_t);
     if (actual_img.data) {
-      EXPECT_EQ(CVTensor(expect_img) == CVTensor(actual_img), true);
+      EXPECT_EQ(*expect_img_t == *actual_img_t, true);
     } else {
       MS_LOG(ERROR) << "Not pass verification! Image data is null.";
       EXPECT_EQ(0, 1);
@@ -223,7 +226,7 @@ bool BBoxOpCommon::LoadAnnotationFile(const std::string &path, std::shared_ptr<T
     object = object->NextSiblingElement("object");  // Read next BBox if exists
   }
   std::shared_ptr<Tensor> ret_value;
-  Status s = Tensor::CreateTensor(&ret_value, return_value_list, TensorShape({bbox_count, bbox_val_count}));
+  Status s = Tensor::CreateFromVector(return_value_list, TensorShape({bbox_count, bbox_val_count}), &ret_value);
   EXPECT_TRUE(s.IsOk());
   (*target_BBox) = ret_value;  // load bbox from file into return
   return true;

tests/ut/cpp/dataset/common/cvop_common.cc

@@ -52,9 +52,11 @@ std::string CVOpCommon::GetFilename() {
 
 void CVOpCommon::GetInputImage(std::string filename) {
   try {
-    Tensor::CreateTensor(&raw_input_tensor_, filename);
+    Tensor::CreateFromFile(filename, &raw_input_tensor_);
     raw_cv_image_ = cv::imread(filename, cv::ImreadModes::IMREAD_COLOR);
-    input_tensor_ = std::dynamic_pointer_cast<Tensor>(std::make_shared<CVTensor>(raw_cv_image_));
+    std::shared_ptr<CVTensor> input_cv_tensor;
+    CVTensor::CreateFromMat(raw_cv_image_, &input_cv_tensor);
+    input_tensor_ = std::dynamic_pointer_cast<Tensor>(input_cv_tensor);
     SwapRedAndBlue(input_tensor_, &input_tensor_);
     if (raw_cv_image_.data) {
       MS_LOG(INFO) << "Reading was successful. Height:" << raw_cv_image_.rows << " Width: " << raw_cv_image_.cols

tests/ut/cpp/dataset/concatenate_op_test.cc

@@ -29,14 +29,14 @@ class MindDataTestConcatenateOp : public UT::Common {
 
 TEST_F(MindDataTestConcatenateOp, TestOp) {
   MS_LOG(INFO) << "Doing MindDataTestConcatenate-TestOp.";
-  uint64_t labels[3] = {1, 1, 2};
+  std::vector<uint64_t> labels = {1, 1, 2};
   TensorShape shape({3});
-  std::shared_ptr<Tensor> input =
+  std::shared_ptr<Tensor> input;
-    std::make_shared<Tensor>(shape, DataType(DataType::DE_UINT64), reinterpret_cast<unsigned char *>(labels));
+  Tensor::CreateFromVector(labels, &input);
 
-  uint64_t append_labels[3] = {4, 4, 4};
+  std::vector<uint64_t> append_labels = {4, 4, 4};
-  std::shared_ptr<Tensor> append =
+  std::shared_ptr<Tensor> append;
-    std::make_shared<Tensor>(shape, DataType(DataType::DE_UINT64), reinterpret_cast<unsigned char *>(append_labels));
+  Tensor::CreateFromVector(append_labels, &append);
 
   std::shared_ptr<Tensor> output;
   std::unique_ptr<ConcatenateOp> op(new ConcatenateOp(0, nullptr, append));
@@ -44,10 +44,11 @@ TEST_F(MindDataTestConcatenateOp, TestOp) {
   in.push_back(input);
   TensorRow out_row;
   Status s = op->Compute(in, &out_row);
-  uint64_t out[6] = {1, 1, 2, 4, 4, 4};
+  std::vector<uint64_t> out = {1, 1, 2, 4, 4, 4};
+
+  std::shared_ptr<Tensor> expected;
+  Tensor::CreateFromVector(out, &expected);
 
-  std::shared_ptr<Tensor> expected =
-    std::make_shared<Tensor>(TensorShape{6}, DataType(DataType::DE_UINT64), reinterpret_cast<unsigned char *>(out));
   output = out_row[0];
   EXPECT_TRUE(s.IsOk());
   ASSERT_TRUE(output->shape() == expected->shape());

tests/ut/cpp/dataset/duplicate_op_test.cc

@@ -32,9 +32,9 @@ class MindDataTestDuplicateOp : public UT::Common {
 
 TEST_F(MindDataTestDuplicateOp, Basics) {
   std::shared_ptr<Tensor> t;
-  Tensor::CreateTensor(&t, std::vector<uint32_t>({1, 2, 3, 4, 5, 6}));
+  Tensor::CreateFromVector(std::vector<uint32_t>({1, 2, 3, 4, 5, 6}), &t);
   std::shared_ptr<Tensor> v;
-  Tensor::CreateTensor(&v, std::vector<uint32_t>({3}), TensorShape::CreateScalar());
+  Tensor::CreateFromVector(std::vector<uint32_t>({3}), TensorShape::CreateScalar(), &v);
   std::shared_ptr<DuplicateOp> op = std::make_shared<DuplicateOp>();
   TensorRow in;
   in.push_back(t);

tests/ut/cpp/dataset/fill_op_test.cc

@@ -29,23 +29,20 @@ class MindDataTestFillOp : public UT::Common {
 
 TEST_F(MindDataTestFillOp, TestOp) {
   MS_LOG(INFO) << "Doing MindDataTestFillOp-TestOp.";
-  uint64_t labels[3] = {1, 1, 2};
+  std::vector<uint64_t> labels = {1, 1, 2};
-  TensorShape shape({3});
+  std::shared_ptr<Tensor> input;
-  std::shared_ptr<Tensor> input =
+  Tensor::CreateFromVector(labels, &input);
-    std::make_shared<Tensor>(shape, DataType(DataType::DE_UINT64), reinterpret_cast<unsigned char *>(labels));
 
-  TensorShape fill_shape({});
+  std::shared_ptr<Tensor> fill_tensor;
-  std::shared_ptr<Tensor> fill_tensor = std::make_shared<Tensor>(fill_shape, DataType(DataType::DE_UINT64));
+  Tensor::CreateScalar<uint64_t>(4, &fill_tensor);
-  fill_tensor->SetItemAt<uint64_t>({}, 4);
 
   std::shared_ptr<Tensor> output;
   std::unique_ptr<FillOp> op(new FillOp(fill_tensor));
   Status s = op->Compute(input, &output);
 
-  uint64_t out[3] = {4, 4, 4};
+  std::vector<uint64_t> out = {4, 4, 4};
-
+  std::shared_ptr<Tensor> expected;
-  std::shared_ptr<Tensor> expected =
+  Tensor::CreateFromVector(out, &expected);
-    std::make_shared<Tensor>(TensorShape{3}, DataType(DataType::DE_UINT64), reinterpret_cast<unsigned char *>(out));
 
   EXPECT_TRUE(s.IsOk());
   ASSERT_TRUE(output->shape() == expected->shape());
@@ -59,23 +56,20 @@ TEST_F(MindDataTestFillOp, TestOp) {
 
 TEST_F(MindDataTestFillOp, TestCasting) {
   MS_LOG(INFO) << "Doing MindDataTestFillOp-TestCasting.";
-  uint64_t labels[3] = {0, 1, 2};
+  std::vector<uint64_t> labels = {0, 1, 2};
-  TensorShape shape({3});
+  std::shared_ptr<Tensor> input;
-  std::shared_ptr<Tensor> input =
+  Tensor::CreateFromVector(labels, &input);
-    std::make_shared<Tensor>(shape, DataType(DataType::DE_UINT64), reinterpret_cast<unsigned char *>(labels));
 
-  TensorShape fill_shape({});
+  std::shared_ptr<Tensor> fill_tensor;
-  std::shared_ptr<Tensor> fill_tensor = std::make_shared<Tensor>(fill_shape, DataType(DataType::DE_FLOAT32));
+  Tensor::CreateScalar<float>(2.0, &fill_tensor);
-  fill_tensor->SetItemAt<float>({}, 2.0);
 
   std::shared_ptr<Tensor> output;
   std::unique_ptr<FillOp> op(new FillOp(fill_tensor));
   Status s = op->Compute(input, &output);
 
-  uint64_t out[3] = {2, 2, 2};
+  std::vector<uint64_t> out = {2, 2, 2};
-
+  std::shared_ptr<Tensor> expected;
-  std::shared_ptr<Tensor> expected =
+  Tensor::CreateFromVector(out, &expected);
-    std::make_shared<Tensor>(TensorShape{3}, DataType(DataType::DE_UINT64), reinterpret_cast<unsigned char *>(out));
 
   ASSERT_TRUE(output->shape() == expected->shape());
   ASSERT_TRUE(output->type() == expected->type());
@@ -90,15 +84,15 @@ TEST_F(MindDataTestFillOp, TestCasting) {
 
 TEST_F(MindDataTestFillOp, ScalarFill) {
   MS_LOG(INFO) << "Doing MindDataTestFillOp-ScalarFill.";
-  uint64_t labels[3] = {0, 1, 2};
+  std::vector<uint64_t> labels = {0, 1, 2};
-  TensorShape shape({3});
+  std::shared_ptr<Tensor> input;
-  std::shared_ptr<Tensor> input =
+  Tensor::CreateFromVector(labels, &input);
-    std::make_shared<Tensor>(shape, DataType(DataType::DE_UINT64), reinterpret_cast<unsigned char *>(labels));
 
   TensorShape fill_shape({2});
-  uint64_t fill_labels[3] = {0, 1};
+  std::vector<uint64_t> fill_labels = {0, 1};
-  std::shared_ptr<Tensor> fill_tensor =
+  std::shared_ptr<Tensor> fill_tensor;
-    std::make_shared<Tensor>(fill_shape, DataType(DataType::DE_UINT64), reinterpret_cast<unsigned char *>(fill_labels));
+  Tensor::CreateFromVector(fill_labels, &fill_tensor);
+
   std::shared_ptr<Tensor> output;
   std::unique_ptr<FillOp> op(new FillOp(fill_tensor));
   Status s = op->Compute(input, &output);
@@ -112,12 +106,11 @@ TEST_F(MindDataTestFillOp, ScalarFill) {
 TEST_F(MindDataTestFillOp, StringFill) {
   MS_LOG(INFO) << "Doing MindDataTestFillOp-StringFill.";
   std::vector<std::string> strings = {"xyzzy", "plugh", "abracadabra"};
-  TensorShape shape({3});
+  std::shared_ptr<Tensor> input;
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>(strings, shape);
+  Tensor::CreateFromVector(strings, &input);
 
-  TensorShape fill_shape({});
+  std::shared_ptr<Tensor> fill_tensor;
-  std::string fill_string = "hello";
+  Tensor::CreateScalar<std::string>("hello", &fill_tensor);
-  std::shared_ptr<Tensor> fill_tensor = std::make_shared<Tensor>(fill_string);
 
   std::shared_ptr<Tensor> output;
 
@@ -125,8 +118,8 @@ TEST_F(MindDataTestFillOp, StringFill) {
   Status s = op->Compute(input, &output);
 
   std::vector<std::string> expected_strings = {"hello", "hello", "hello"};
-  TensorShape expected_shape({3});
+  std::shared_ptr<Tensor> expected;
-  std::shared_ptr<Tensor> expected = std::make_shared<Tensor>(expected_strings, expected_shape);
+  Tensor::CreateFromVector(expected_strings, &expected);
 
   EXPECT_TRUE(s.IsOk());
   ASSERT_TRUE(output->shape() == expected->shape());
@@ -142,12 +135,11 @@ TEST_F(MindDataTestFillOp, StringFill) {
 TEST_F(MindDataTestFillOp, NumericToString) {
   MS_LOG(INFO) << "Doing MindDataTestFillOp-NumericToString.";
   std::vector<std::string> strings = {"xyzzy", "plugh", "abracadabra"};
-  TensorShape shape({3});
+  std::shared_ptr<Tensor> input;
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>(strings, shape);
+  Tensor::CreateFromVector(strings, &input);
 
-  TensorShape fill_shape({});
+  std::shared_ptr<Tensor> fill_tensor;
-  std::shared_ptr<Tensor> fill_tensor = std::make_shared<Tensor>(fill_shape, DataType(DataType::DE_FLOAT32));
+  Tensor::CreateScalar<float>(2.0, &fill_tensor);
-  fill_tensor->SetItemAt<float>({}, 2.0);
 
   std::shared_ptr<Tensor> output;
 
@@ -162,14 +154,12 @@ TEST_F(MindDataTestFillOp, NumericToString) {
 
 TEST_F(MindDataTestFillOp, StringToNumeric) {
   MS_LOG(INFO) << "Doing MindDataTestFillOp-StringToNumeric.";
-  uint64_t labels[3] = {0, 1, 2};
+  std::vector<uint64_t> labels = {0, 1, 2};
-  TensorShape shape({3});
+  std::shared_ptr<Tensor> input;
-  std::shared_ptr<Tensor> input =
+  Tensor::CreateFromVector(labels, &input);
-    std::make_shared<Tensor>(shape, DataType(DataType::DE_UINT64), reinterpret_cast<unsigned char *>(labels));
 
-  TensorShape fill_shape({});
+  std::shared_ptr<Tensor> fill_tensor;
-  std::string fill_string = "hello";
+  Tensor::CreateScalar<std::string>("hello", &fill_tensor);
-  std::shared_ptr<Tensor> fill_tensor = std::make_shared<Tensor>(fill_string);
 
   std::shared_ptr<Tensor> output;
 

tests/ut/cpp/dataset/image_folder_op_test.cc

@@ -68,8 +68,7 @@ std::shared_ptr<ImageFolderOp> ImageFolder(int64_t num_works, int64_t rows, int6
 Status Create1DTensor(std::shared_ptr<Tensor> *sample_ids, int64_t num_elements, unsigned char *data = nullptr,
                       DataType::Type data_type = DataType::DE_UINT32) {
   TensorShape shape(std::vector<int64_t>(1, num_elements));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(sample_ids, TensorImpl::kFlexible, shape, DataType(data_type), data));
+  RETURN_IF_NOT_OK(Tensor::CreateFromMemory(shape, DataType(data_type), data, sample_ids));
-  (*sample_ids)->AllocateBuffer((*sample_ids)->SizeInBytes());  // allocate memory in case user forgets!
 
   return Status::OK();
 }

tests/ut/cpp/dataset/jieba_tokenizer_op_test.cc

@@ -42,7 +42,8 @@ TEST_F(MindDataTestJiebaTokenizerOp, TestJieba_opFuntions) {
   TensorRow input, output;
   std::unique_ptr<JiebaTokenizerOp> op(new JiebaTokenizerOp(hmm_path, mp_path));
 
-  std::shared_ptr<Tensor> input_tensor = std::make_shared<Tensor>("今天天气太好了我们一起去外面玩吧");
+  std::shared_ptr<Tensor> input_tensor;
+  Tensor::CreateScalar<std::string>("今天天气太好了我们一起去外面玩吧", &input_tensor);
   input.push_back(input_tensor);
   Status s = op->Compute(input, &output);
   EXPECT_TRUE(s.IsOk());
@@ -66,7 +67,8 @@ TEST_F(MindDataTestJiebaTokenizerOp, TestJieba_opAdd) {
   std::unique_ptr<JiebaTokenizerOp> op(new JiebaTokenizerOp(hmm_path, mp_path));
 
   op->AddWord("男默女泪");
-  std::shared_ptr<Tensor> input_tensor = std::make_shared<Tensor>("男默女泪");
+  std::shared_ptr<Tensor> input_tensor;
+  Tensor::CreateScalar<std::string>("男默女泪", &input_tensor);
   input.push_back(input_tensor);
   Status s = op->Compute(input, &output);
   EXPECT_TRUE(s.IsOk());
@@ -84,7 +86,8 @@ TEST_F(MindDataTestJiebaTokenizerOp, TestJieba_opEmpty) {
   std::unique_ptr<JiebaTokenizerOp> op(new JiebaTokenizerOp(hmm_path, mp_path));
 
   op->AddWord("男默女泪");
-  std::shared_ptr<Tensor> input_tensor = std::make_shared<Tensor>("");
+  std::shared_ptr<Tensor> input_tensor;
+  Tensor::CreateScalar<std::string>("", &input_tensor);
   input.push_back(input_tensor);
   Status s = op->Compute(input, &output);
   EXPECT_TRUE(s.IsOk());

tests/ut/cpp/dataset/manifest_op_test.cc

@@ -71,9 +71,9 @@ TEST_F(MindDataTestManifest, TestSequentialManifestWithRepeat) {
     di.GetNextAsMap(&tensor_map);
     EXPECT_TRUE(rc.IsOk());
     uint64_t i = 0;
-    uint32_t label = 0;
+    int32_t label = 0;
     while (tensor_map.size() != 0) {
-      tensor_map["label"]->GetItemAt<uint32_t>(&label, {});
+      tensor_map["label"]->GetItemAt<int32_t>(&label, {});
       EXPECT_TRUE(res[i] == label);
       MS_LOG(DEBUG) << "row: " << i << "\t" << tensor_map["image"]->shape() << "label:" << label << "\n";
       i++;
@@ -101,9 +101,9 @@ TEST_F(MindDataTestManifest, TestSubsetRandomSamplerManifest) {
     rc = di.GetNextAsMap(&tensor_map);
     EXPECT_TRUE(rc.IsOk());
     uint64_t i = 0;
-    uint32_t label = 0;
+    int32_t label = 0;
     while (tensor_map.size() != 0) {
-      tensor_map["label"]->GetItemAt<uint32_t>(&label, {});
+      tensor_map["label"]->GetItemAt<int32_t>(&label, {});
       i++;
       di.GetNextAsMap(&tensor_map);
       EXPECT_EQ(label, 1);
@@ -131,9 +131,9 @@ TEST_F(MindDataTestManifest, MindDataTestManifestClassIndex) {
     di.GetNextAsMap(&tensor_map);
     EXPECT_TRUE(rc.IsOk());
     uint64_t i = 0;
-    uint32_t label = 0;
+    int32_t label = 0;
     while (tensor_map.size() != 0) {
-      tensor_map["label"]->GetItemAt<uint32_t>(&label, {});
+      tensor_map["label"]->GetItemAt<int32_t>(&label, {});
       EXPECT_TRUE(label == res[i]);
       MS_LOG(DEBUG) << "row: " << i << "\t" << tensor_map["image"]->shape() << "label:" << label << "\n";
       i++;
@@ -160,9 +160,9 @@ TEST_F(MindDataTestManifest, MindDataTestManifestNumSamples) {
     di.GetNextAsMap(&tensor_map);
     EXPECT_TRUE(rc.IsOk());
     uint64_t i = 0;
-    uint32_t label = 0;
+    int32_t label = 0;
     while (tensor_map.size() != 0) {
-      tensor_map["label"]->GetItemAt<uint32_t>(&label, {});
+      tensor_map["label"]->GetItemAt<int32_t>(&label, {});
       EXPECT_TRUE(0 == label);
       MS_LOG(DEBUG) << "row: " << i << "\t" << tensor_map["image"]->shape() << "label:" << label << "\n";
       i++;
@@ -176,7 +176,7 @@ TEST_F(MindDataTestManifest, MindDataTestManifestEval) {
   std::string file = datasets_root_path_ + "/testManifestData/cpp.json";
   int64_t num_samples = 1;
   int64_t start_index = 0;
-  auto seq_sampler = std::make_shared<SequentialSampler>(num_samples, start_index);  
+  auto seq_sampler = std::make_shared<SequentialSampler>(num_samples, start_index);
   auto tree = Build({Manifest(16, 2, 32, file, "eval", std::move(seq_sampler), {})});
   tree->Prepare();
   Status rc = tree->Launch();
@@ -189,9 +189,9 @@ TEST_F(MindDataTestManifest, MindDataTestManifestEval) {
     di.GetNextAsMap(&tensor_map);
     EXPECT_TRUE(rc.IsOk());
     uint64_t i = 0;
-    uint32_t label = 0;
+    int32_t label = 0;
     while (tensor_map.size() != 0) {
-      tensor_map["label"]->GetItemAt<uint32_t>(&label, {});
+      tensor_map["label"]->GetItemAt<int32_t>(&label, {});
       EXPECT_TRUE(0 == label);
       MS_LOG(DEBUG) << "row: " << i << "\t" << tensor_map["image"]->shape() << "label:" << label << "\n";
       i++;

tests/ut/cpp/dataset/mask_test.cc

@@ -38,9 +38,9 @@ class MindDataTestMaskOp : public UT::Common {
 
 TEST_F(MindDataTestMaskOp, Basics) {
   std::shared_ptr<Tensor> t;
-  Tensor::CreateTensor(&t, std::vector<uint32_t>({1, 2, 3, 4, 5, 6}));
+  Tensor::CreateFromVector(std::vector<uint32_t>({1, 2, 3, 4, 5, 6}), &t);
   std::shared_ptr<Tensor> v;
-  Tensor::CreateTensor(&v, std::vector<uint32_t>({3}), TensorShape::CreateScalar());
+  Tensor::CreateFromVector(std::vector<uint32_t>({3}), TensorShape::CreateScalar(), &v);
   std::shared_ptr<MaskOp> op = std::make_shared<MaskOp>(RelationalOp::kEqual, v, DataType(DataType::DE_UINT16));
   std::shared_ptr<Tensor> out;
   ASSERT_TRUE(op->Compute(t, &out).IsOk());

tests/ut/cpp/dataset/one_hot_op_test.cc

@@ -29,19 +29,17 @@ class MindDataTestOneHotOp : public UT::Common {
 
 TEST_F(MindDataTestOneHotOp, TestOp) {
   MS_LOG(INFO) << "Doing MindDataTestOneHotOp.";
-  uint64_t labels[3] = {0, 1, 2};
+  std::vector<uint64_t> labels = {0, 1, 2};
-  TensorShape shape({3});
+  std::shared_ptr<Tensor> input;
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>(shape, DataType(DataType::DE_UINT64),
+  Tensor::CreateFromVector(labels, &input);
-                                                           reinterpret_cast <unsigned char *>(labels));
   std::shared_ptr<Tensor> output;
 
   std::unique_ptr<OneHotOp> op(new OneHotOp(5));
   Status s = op->Compute(input, &output);
-  uint64_t out[15] = {1, 0, 0, 0, 0,
+  std::vector<uint64_t> out = {1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0};
-                      0, 1, 0, 0, 0,
+  std::shared_ptr<Tensor> expected;
-                      0, 0, 1, 0, 0};
+  Tensor::CreateFromVector(out, TensorShape{3, 5}, &expected);
-  std::shared_ptr<Tensor> expected = std::make_shared<Tensor>(TensorShape{3, 5}, DataType(DataType::DE_UINT64),
+
-                                                              reinterpret_cast <unsigned char *>(out));
   EXPECT_TRUE(s.IsOk());
   ASSERT_TRUE(output->shape() == expected->shape());
   ASSERT_TRUE(output->type() == expected->type());

tests/ut/cpp/dataset/pad_end_op_test.cc

@@ -35,44 +35,40 @@ TEST_F(MindDataTestPadEndOp, TestOp) {
   TensorShape pad_data_shape({1});
 
   // prepare input tensor
-  float_t orig1[4] = {1, 1, 1, 1};
+  std::vector<float> orig1 = {1, 1, 1, 1};
   TensorShape input_shape1({2, 2});
   std::vector<TensorShape> input_shape1_vector = {input_shape1};
-  std::shared_ptr<Tensor> input1 =
+  std::shared_ptr<Tensor> input1;
-    std::make_shared<Tensor>(input_shape1, DataType(DataType::DE_FLOAT32), reinterpret_cast<unsigned char *>(orig1));
+  Tensor::CreateFromVector(orig1, input_shape1, &input1);
 
   // pad_shape
   TensorShape pad_shape1[3] = {TensorShape({3, 3}), TensorShape({2, 4}), TensorShape({4, 2})};
 
   // value to pad
-  float_t pad_data1[3][1] = {0, 3.5, 3.5};
+  std::vector<std::vector<float>> pad_data1 = {{0}, {3.5}, {3.5}};
 
   std::shared_ptr<Tensor> expected1[3];
 
   // expected tensor output for testunit 1
-  float_t out1[9] = {1, 1, 0, 1, 1, 0, 0, 0, 0};
+  std::vector<float> out1 = {1, 1, 0, 1, 1, 0, 0, 0, 0};
-
+  Tensor::CreateFromVector(out1, pad_shape1[0], &(expected1[0]));
-  expected1[0] =
-    std::make_shared<Tensor>(pad_shape1[0], DataType(DataType::DE_FLOAT32), reinterpret_cast<unsigned char *>(out1));
 
   // expected tensor output for testunit 2
-  float_t out2[8] = {1, 1, 3.5, 3.5, 1, 1, 3.5, 3.5};
+  std::vector<float> out2 = {1, 1, 3.5, 3.5, 1, 1, 3.5, 3.5};
-
+  Tensor::CreateFromVector(out2, pad_shape1[1], &(expected1[1]));
-  expected1[1] =
-    std::make_shared<Tensor>(pad_shape1[1], DataType(DataType::DE_FLOAT32), reinterpret_cast<unsigned char *>(out2));
 
   // expected tensor output for testunit 3
-  float_t out3[8] = {1, 1, 1, 1, 3.5, 3.5, 3.5, 3.5};
+  std::vector<float> out3 = {1, 1, 1, 1, 3.5, 3.5, 3.5, 3.5};
-
+  Tensor::CreateFromVector(out3, pad_shape1[2], &(expected1[2]));
-  expected1[2] =
-    std::make_shared<Tensor>(pad_shape1[2], DataType(DataType::DE_FLOAT32), reinterpret_cast<unsigned char *>(out3));
 
   // run the PadEndOp
   for (auto i = 0; i < 3; i++) {
     std::shared_ptr<Tensor> output;
     std::vector<TensorShape> output_shape = {TensorShape({})};
-    std::shared_ptr<Tensor> pad_value1 = std::make_shared<Tensor>(pad_data_shape, DataType(DataType::DE_FLOAT32),
+
-                                                                  reinterpret_cast<unsigned char *>(pad_data1[i]));
+    std::shared_ptr<Tensor> pad_value1;
+    Tensor::CreateFromVector(pad_data1[i], pad_data_shape, &pad_value1);
+
     std::unique_ptr<PadEndOp> op(new PadEndOp(pad_shape1[i], pad_value1));
     Status s = op->Compute(input1, &output);
 
@@ -96,7 +92,7 @@ TEST_F(MindDataTestPadEndOp, TestOp) {
   TensorShape input_shape2({2});
   std::vector<TensorShape> input_shape2_vector = {input_shape2};
   std::shared_ptr<Tensor> input2;
-  Tensor::CreateTensor(&input2, orig2, input_shape2);
+  Tensor::CreateFromVector(orig2, input_shape2, &input2);
 
   // pad_shape
   TensorShape pad_shape2[3] = {TensorShape({5}), TensorShape({2}), TensorShape({10})};
@@ -112,7 +108,7 @@ TEST_F(MindDataTestPadEndOp, TestOp) {
 
   for (auto i = 0; i < 3; i++) {
     // pad value
-    Tensor::CreateTensor(&pad_value2[i], pad_data2[i], pad_data_shape);
+    Tensor::CreateFromVector(pad_data2[i], pad_data_shape, &pad_value2[i]);
 
     std::shared_ptr<Tensor> output;
     std::vector<TensorShape> output_shape = {TensorShape({})};
@@ -121,7 +117,7 @@ TEST_F(MindDataTestPadEndOp, TestOp) {
 
     Status s = op->Compute(input2, &output);
 
-    Tensor::CreateTensor(&expected2[i], outstring[i], pad_shape2[i]);
+    Tensor::CreateFromVector(outstring[i], pad_shape2[i], &expected2[i]);
 
     EXPECT_TRUE(s.IsOk());
     ASSERT_TRUE(output->shape() == expected2[i]->shape());

tests/ut/cpp/dataset/sentence_piece_vocab_op_test.cc

@@ -93,7 +93,6 @@ TEST_F(MindDataTestSentencePieceVocabOp, TestSentencePieceFromDatasetFuntions) {
     rc = di.FetchNextTensorRow(&tensor_list);
   }
   ASSERT_TRUE(rc.IsOk());
-
 }
 
 TEST_F(MindDataTestSentencePieceVocabOp, TestSentencePieceFromFileFuntions) {
@@ -166,9 +165,10 @@ TEST_F(MindDataTestSentencePieceVocabOp, TestSentencePieceTokenizerFuntions) {
     rc = di.FetchNextTensorRow(&tensor_list);
   }
   std::shared_ptr<Tensor> output_tensor;
-  std::unique_ptr<SentencePieceTokenizerOp> op(new SentencePieceTokenizerOp(spm,
+  std::unique_ptr<SentencePieceTokenizerOp> op(
-    SPieceTokenizerLoadType::kModel, SPieceTokenizerOutType::kString));
+    new SentencePieceTokenizerOp(spm, SPieceTokenizerLoadType::kModel, SPieceTokenizerOutType::kString));
-  std::shared_ptr<Tensor> input_tensor = std::make_shared<Tensor>("I saw a girl with a telescope.");
+  std::shared_ptr<Tensor> input_tensor;
+  Tensor::CreateScalar<std::string>("I saw a girl with a telescope.", &input_tensor);
   Status s = op->Compute(input_tensor, &output_tensor);
 
   std::vector<std::string> expect;

tests/ut/cpp/dataset/sliding_window_op_test.cc

@@ -31,15 +31,17 @@ TEST_F(MindDataTestSlidingWindowOp, Compute) {
   MS_LOG(INFO) << "Doing MindDataTestSlidingWindowOp->Compute.";
   std::vector<std::string> strings = {"one", "two", "three", "four", "five", "six", "seven", "eight"};
   TensorShape shape({static_cast<dsize_t>(strings.size())});
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>(strings, shape);
+  std::shared_ptr<Tensor> input;
+  Tensor::CreateFromVector(strings, shape, &input);
   std::shared_ptr<Tensor> output;
 
   std::unique_ptr<SlidingWindowOp> op(new SlidingWindowOp(3, 0));
   Status s = op->Compute(input, &output);
 
-  std::vector<std::string> out = {"one", "two", "three", "two", "three", "four", "three", "four", "five",
+  std::vector<std::string> out = {"one",  "two",  "three", "two",  "three", "four",  "three", "four",  "five",
-                                  "four", "five", "six", "five", "six", "seven", "six", "seven", "eight"};
+                                  "four", "five", "six",   "five", "six",   "seven", "six",   "seven", "eight"};
-  std::shared_ptr<Tensor> expected = std::make_shared<Tensor>(out, TensorShape({6, 3}));
+  std::shared_ptr<Tensor> expected;
+  Tensor::CreateFromVector(out, TensorShape({6, 3}), &expected);
 
   ASSERT_TRUE(output->shape() == expected->shape());
   ASSERT_TRUE(output->type() == expected->type());
@@ -54,7 +56,8 @@ TEST_F(MindDataTestSlidingWindowOp, OutputShape) {
   MS_LOG(INFO) << "Doing MindDataTestSlidingWindowOp->OutputShape.";
   std::vector<std::string> strings = {"one", "two", "three", "four", "five", "six", "seven", "eight"};
   TensorShape shape({static_cast<dsize_t>(strings.size())});
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>(strings, shape);
+  std::shared_ptr<Tensor> input;
+  Tensor::CreateFromVector(strings, shape, &input);
   std::vector<TensorShape> input_shape = {input->shape()};
   std::vector<TensorShape> output_shape = {TensorShape({})};
 

tests/ut/cpp/dataset/stand_alone_samplers_test.cc

@@ -30,8 +30,7 @@ using namespace mindspore::dataset;
 
 Status CreateINT64Tensor(std::shared_ptr<Tensor> *sample_ids, int64_t num_elements, unsigned char *data = nullptr) {
   TensorShape shape(std::vector<int64_t>(1, num_elements));
-  RETURN_IF_NOT_OK(Tensor::CreateTensor(sample_ids, TensorImpl::kFlexible, shape, DataType(DataType::DE_INT64), data));
+  RETURN_IF_NOT_OK(Tensor::CreateFromMemory(shape, DataType(DataType::DE_INT64), data, sample_ids));
-  (*sample_ids)->AllocateBuffer((*sample_ids)->SizeInBytes());  // allocate memory in case user forgets!
 
   return Status::OK();
 }
@@ -54,8 +53,7 @@ TEST_F(MindDataTestStandAloneSampler, TestDistributedSampler) {
                         {0, 17, 4, 10, 14, 8, 15}, {13, 9, 16, 3, 2, 19, 12}, {1, 11, 6, 18, 7, 5, 0}};
   for (int i = 0; i < 6; i++) {
     std::shared_ptr<Tensor> t;
-    Tensor::CreateTensor(&t, TensorImpl::kFlexible, TensorShape({7}),
+    Tensor::CreateFromMemory(TensorShape({7}), DataType(DataType::DE_INT64), (unsigned char *)(res[i]), &t);
-                         DataType(DataType::DE_INT64), (unsigned char *)(res[i]));
     row.push_back(t);
   }
   MockStorageOp mock(20);

tests/ut/cpp/dataset/tensor_string_test.cc

@@ -35,13 +35,15 @@ class MindDataTestStringTensorDE : public UT::Common {
 };
 
 TEST_F(MindDataTestStringTensorDE, Basics) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>("Hi");
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateScalar<std::string>("Hi", &t);
   ASSERT_TRUE(t->shape() == TensorShape({}));
   std::string_view s = "";
   t->GetItemAt(&s, {});
   ASSERT_TRUE(s == "Hi");
 
-  std::shared_ptr<Tensor> t2 = std::make_shared<Tensor>(std::vector<std::string>{"Hi", "Bye"});
+  std::shared_ptr<Tensor> t2;
+  Tensor::CreateFromVector(std::vector<std::string>{"Hi", "Bye"}, &t2);
   ASSERT_TRUE(t2->shape() == TensorShape({2}));
   t2->GetItemAt(&s, {0});
   ASSERT_TRUE(s == "Hi");
@@ -49,7 +51,9 @@ TEST_F(MindDataTestStringTensorDE, Basics) {
   ASSERT_TRUE(s == "Bye");
 
   std::vector<std::string> strings{"abc", "defg", "hi", "klmno", "123", "789"};
-  std::shared_ptr<Tensor> t3 = std::make_shared<Tensor>(strings, TensorShape({2, 3}));
+  std::shared_ptr<Tensor> t3;
+  Tensor::CreateFromVector(strings, TensorShape({2, 3}), &t3);
+
   ASSERT_TRUE(t3->shape() == TensorShape({2, 3}));
   uint32_t index = 0;
   for (uint32_t i = 0; i < 2; i++) {
@@ -62,8 +66,10 @@ TEST_F(MindDataTestStringTensorDE, Basics) {
 }
 
 TEST_F(MindDataTestStringTensorDE, Basics2) {
-  std::shared_ptr<Tensor> t =
+  std::shared_ptr<Tensor> t;
-    std::make_shared<Tensor>(std::vector<std::string>{"abc", "defg", "hi", "klmno", "123", "789"}, TensorShape({2, 3}));
+  Tensor::CreateFromVector(std::vector<std::string>{"abc", "defg", "hi", "klmno", "123", "789"}, TensorShape({2, 3}),
+                           &t);
+
   ASSERT_TRUE(t->SizeInBytes() == 6 * 5 + 20 + 4);
   std::vector<uint32_t> offsets = {0, 4, 9, 12, 18, 22, 26};
   uint32_t ctr = 0;
@@ -86,7 +92,8 @@ TEST_F(MindDataTestStringTensorDE, Basics2) {
 
 TEST_F(MindDataTestStringTensorDE, Empty) {
   std::vector<std::string> strings{"abc", "defg", "", "", "123", ""};
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(strings, TensorShape({2, 3}));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateFromVector(strings, TensorShape({2, 3}), &t);
   //  abc_defg___123__
   //  0123456789012345
   ASSERT_TRUE(t->SizeInBytes() == 6 * 5 + 10 + 4);
@@ -112,7 +119,9 @@ TEST_F(MindDataTestStringTensorDE, Empty) {
 
 TEST_F(MindDataTestStringTensorDE, SetItem) {
   std::vector<std::string> strings{"abc", "defg", "hi", "klmno", "123", "789"};
-  std::shared_ptr<Tensor> t3 = std::make_shared<Tensor>(strings, TensorShape({2, 3}));
+  std::shared_ptr<Tensor> t3;
+  Tensor::CreateFromVector(strings, TensorShape({2, 3}), &t3);
+
   ASSERT_TRUE(t3->shape() == TensorShape({2, 3}));
 
   t3->SetItemAt({0, 1}, std::string{"xyzz"});
@@ -136,7 +145,8 @@ TEST_F(MindDataTestStringTensorDE, SetItem) {
 
 TEST_F(MindDataTestStringTensorDE, Iterator) {
   std::vector<std::string> strings{"abc", "defg", "hi", "klmno", "123", "789"};
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(strings, TensorShape({2, 3}));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateFromVector(strings, TensorShape({2, 3}), &t);
   uint32_t index = 0;
   auto itr = t->begin<std::string_view>();
   for (; itr != t->end<std::string_view>(); itr++) {

tests/ut/cpp/dataset/tensor_test.cc

@@ -35,8 +35,9 @@ class MindDataTestTensorDE : public UT::Common {
 };
 
 TEST_F(MindDataTestTensorDE, Basics) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({2, 3}), DataType(DataType::DE_UINT64));
+  std::shared_ptr<Tensor> t;
-  ASSERT_TRUE((t->AllocateBuffer(t->SizeInBytes())).IsOk());
+  Tensor::CreateEmpty(TensorShape({2, 3}), DataType(DataType::DE_UINT64), &t);
+
   ASSERT_EQ(t->shape(), TensorShape({2, 3}));
   ASSERT_EQ(t->type(), DataType::DE_UINT64);
   ASSERT_EQ(t->SizeInBytes(), 2 * 3 * 8);
@@ -67,28 +68,30 @@ TEST_F(MindDataTestTensorDE, Basics) {
   ASSERT_EQ(t->ToString(), "Tensor (shape: <2,3>, Type: uint64)\n[[1,2,3],[4,5,6]]");
   std::vector<uint64_t> x = {1, 2, 3, 4, 5, 6};
   std::shared_ptr<Tensor> t2;
-  Tensor::CreateTensor(&t2, x, TensorShape({2, 3}));
+  Tensor::CreateFromVector(x, TensorShape({2, 3}), &t2);
 
   ASSERT_EQ(*t == *t2, true);
   ASSERT_EQ(*t != *t2, false);
 }
 
 TEST_F(MindDataTestTensorDE, Fill) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({2, 2}), DataType(DataType::DE_FLOAT32));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({2, 2}), DataType(DataType::DE_FLOAT32), &t);
   t->Fill<float>(2.5);
   std::vector<float> x = {2.5, 2.5, 2.5, 2.5};
   std::shared_ptr<Tensor> t2;
-  Tensor::CreateTensor(&t2, x, TensorShape({2, 2}));
+  Tensor::CreateFromVector(x, TensorShape({2, 2}), &t2);
   ASSERT_EQ(*t == *t2, true);
 }
 
 TEST_F(MindDataTestTensorDE, Reshape) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({2, 2}), DataType(DataType::DE_UINT8));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({2, 2}), DataType(DataType::DE_UINT8), &t);
   t->Fill<uint8_t>(254);
   t->Reshape(TensorShape({4}));
   std::vector<uint8_t> x = {254, 254, 254, 254};
   std::shared_ptr<Tensor> t2;
-  Tensor::CreateTensor(&t2, x);
+  Tensor::CreateFromVector(x, &t2);
 
   ASSERT_EQ(*t == *t2, true);
   Status rc = t->Reshape(TensorShape({5}));
@@ -102,7 +105,8 @@ TEST_F(MindDataTestTensorDE, Reshape) {
 }
 
 TEST_F(MindDataTestTensorDE, CopyTensor) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({}), DataType(DataType::DE_INT16));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({}), DataType(DataType::DE_INT16), &t);
   t->SetItemAt<int16_t>({}, -66);
   ASSERT_EQ(t->shape(), TensorShape({}));
   ASSERT_EQ(t->type(), DataType::DE_INT16);
@@ -125,30 +129,31 @@ TEST_F(MindDataTestTensorDE, CopyTensor) {
 }
 
 TEST_F(MindDataTestTensorDE, InsertTensor) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({2, 3}), DataType(DataType::DE_FLOAT64));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({2, 3}), DataType(DataType::DE_FLOAT64), &t);
   std::vector<double> x = {1.1, 2.1, 3.1};
   std::shared_ptr<Tensor> t2;
-  Tensor::CreateTensor(&t2, x);
+  Tensor::CreateFromVector(x, &t2);
 
   std::vector<double> y = {1.2, 2.2, 3.2};
   std::shared_ptr<Tensor> t3;
-  Tensor::CreateTensor(&t3, y);
+  Tensor::CreateFromVector(y, &t3);
 
   ASSERT_TRUE(t->InsertTensor({0}, t2).OK());
   ASSERT_TRUE(t->InsertTensor({1}, t3).OK());
   std::vector<double> z = {1.1, 2.1, 3.1, 1.2, 2.2, 3.2};
 
   std::shared_ptr<Tensor> t4;
-  Tensor::CreateTensor(&t4, z, TensorShape({2, 3}));
+  Tensor::CreateFromVector(z, TensorShape({2, 3}), &t4);
   ASSERT_EQ(*t == *t4, true);
 
   std::shared_ptr<Tensor> t5;
-  Tensor::CreateTensor<double>(&t5, 0);
+  Tensor::CreateScalar<double>(0, &t5);
 
   ASSERT_TRUE(t->InsertTensor({1, 2}, t5).OK());
   z[5] = 0;
   std::shared_ptr<Tensor> t6;
-  Tensor::CreateTensor(&t6, z, TensorShape({2, 3}));
+  Tensor::CreateFromVector(z, TensorShape({2, 3}), &t6);
 
   ASSERT_EQ(*t == *t6, true);
   ASSERT_EQ(t->InsertTensor({2}, t5).get_code(), StatusCode::kUnexpectedError);
@@ -161,7 +166,8 @@ TEST_F(MindDataTestTensorDE, InsertTensor) {
 
 // Test the bug of Tensor::ToString will exec failed for Tensor which store bool values
 TEST_F(MindDataTestTensorDE, BoolTensor) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({2}), DataType(DataType::DE_BOOL));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({2}), DataType(DataType::DE_BOOL), &t);
   t->SetItemAt<bool>({0}, true);
   t->SetItemAt<bool>({1}, true);
   std::string out = t->ToString();
@@ -169,7 +175,8 @@ TEST_F(MindDataTestTensorDE, BoolTensor) {
 }
 
 TEST_F(MindDataTestTensorDE, GetItemAt) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({2, 2}), DataType(DataType::DE_UINT8));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({2, 2}), DataType(DataType::DE_UINT8), &t);
   t->Fill<uint8_t>(254);
   uint64_t o1;
   t->GetItemAt<uint64_t>(&o1, {0, 0});
@@ -183,7 +190,8 @@ TEST_F(MindDataTestTensorDE, GetItemAt) {
   uint8_t o4;
   t->GetItemAt<uint8_t>(&o4, {1, 1});
   ASSERT_EQ(o4, 254);
-  std::shared_ptr<Tensor> t2 = std::make_shared<Tensor>(TensorShape({2, 2}), DataType(DataType::DE_INT8));
+  std::shared_ptr<Tensor> t2;
+  Tensor::CreateEmpty(TensorShape({2, 2}), DataType(DataType::DE_INT8), &t2);
   t2->Fill<int8_t>(-10);
   int64_t o5;
   t2->GetItemAt<int64_t>(&o5, {0, 0});
@@ -197,7 +205,8 @@ TEST_F(MindDataTestTensorDE, GetItemAt) {
   int8_t o8;
   t2->GetItemAt<int8_t>(&o8, {1, 1});
   ASSERT_EQ(o8, -10);
-  std::shared_ptr<Tensor> t3 = std::make_shared<Tensor>(TensorShape({2, 2}), DataType(DataType::DE_FLOAT32));
+  std::shared_ptr<Tensor> t3;
+  Tensor::CreateEmpty(TensorShape({2, 2}), DataType(DataType::DE_FLOAT32), &t3);
   t3->Fill<float>(1.1);
   double o9;
   t3->GetItemAt<double>(&o9, {0, 0});
@@ -208,9 +217,11 @@ TEST_F(MindDataTestTensorDE, GetItemAt) {
 }
 
 TEST_F(MindDataTestTensorDE, OperatorAssign) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({2, 2}), DataType(DataType::DE_UINT8));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({2, 2}), DataType(DataType::DE_UINT8), &t);
   t->Fill<uint8_t>(1);
-  std::shared_ptr<Tensor> t2 = std::make_shared<Tensor>(TensorShape({2, 2}), DataType(DataType::DE_UINT8));
+  std::shared_ptr<Tensor> t2;
+  Tensor::CreateEmpty(TensorShape({2, 2}), DataType(DataType::DE_UINT8), &t2);
   *t2 = std::move(*t);
   uint8_t o;
   t2->GetItemAt(&o, {0, 0});
@@ -224,18 +235,20 @@ TEST_F(MindDataTestTensorDE, OperatorAssign) {
 }
 
 TEST_F(MindDataTestTensorDE, Strides) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({4, 2, 2}), DataType(DataType::DE_UINT8));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({4, 2, 2}), DataType(DataType::DE_UINT8), &t);
   std::vector<dsize_t> x1 = t->Strides();
   std::vector<dsize_t> x2 = {4, 2, 1};
   ASSERT_EQ(x1, x2);
-  t = std::make_shared<Tensor>(TensorShape({4, 2, 2}), DataType(DataType::DE_UINT32));
+  Tensor::CreateEmpty(TensorShape({4, 2, 2}), DataType(DataType::DE_UINT32), &t);
   x1 = t->Strides();
   x2 = {16, 8, 4};
   ASSERT_EQ(x1, x2);
 }
 
 void checkCvMat(TensorShape shape, DataType type) {
-  std::shared_ptr<CVTensor> t = std::make_shared<CVTensor>(shape, type);
+  std::shared_ptr<CVTensor> t;
+  CVTensor::CreateEmpty(shape, type, &t);
   cv::Mat m = t->mat();
   ASSERT_EQ(m.data, t->GetBuffer());
   ASSERT_EQ(static_cast<uchar>(m.type()) & static_cast<uchar>(CV_MAT_DEPTH_MASK), type.AsCVType());
@@ -289,8 +302,10 @@ TEST_F(MindDataTestTensorDE, CVTensorFromMat) {
   m.at<uint8_t>(0, 1) = 20;
   m.at<uint8_t>(1, 0) = 30;
   m.at<uint8_t>(1, 1) = 40;
-  std::shared_ptr<CVTensor> cvt = std::make_shared<CVTensor>(m);
+  std::shared_ptr<CVTensor> cvt;
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({2, 2}), DataType(DataType::DE_UINT8));
+  CVTensor::CreateFromMat(m, &cvt);
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({2, 2}), DataType(DataType::DE_UINT8), &t);
   t->SetItemAt<uint8_t>({0, 0}, 10);
   t->SetItemAt<uint8_t>({0, 1}, 20);
   t->SetItemAt<uint8_t>({1, 0}, 30);
@@ -302,8 +317,10 @@ TEST_F(MindDataTestTensorDE, CVTensorFromMat) {
   m2.at<uint8_t>(1) = 20;
   m2.at<uint8_t>(2) = 30;
   m2.at<uint8_t>(3) = 40;
-  std::shared_ptr<CVTensor> cvt2 = std::make_shared<CVTensor>(m2);
+  std::shared_ptr<CVTensor> cvt2;
-  std::shared_ptr<Tensor> t2 = std::make_shared<Tensor>(TensorShape({4}), DataType(DataType::DE_UINT8));
+  CVTensor::CreateFromMat(m2, &cvt2);
+  std::shared_ptr<Tensor> t2;
+  Tensor::CreateEmpty(TensorShape({4}), DataType(DataType::DE_UINT8), &t2);
   t2->SetItemAt<uint8_t>({0}, 10);
   t2->SetItemAt<uint8_t>({1}, 20);
   t2->SetItemAt<uint8_t>({2}, 30);
@@ -313,10 +330,12 @@ TEST_F(MindDataTestTensorDE, CVTensorFromMat) {
 }
 
 TEST_F(MindDataTestTensorDE, CVTensorAs) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({3, 2}), DataType(DataType::DE_FLOAT64));
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateEmpty(TensorShape({3, 2}), DataType(DataType::DE_FLOAT64), &t);
   t->Fill<double>(2.2);
   const unsigned char *addr = t->GetBuffer();
-  std::shared_ptr<Tensor> t2 = std::make_shared<Tensor>(TensorShape({3, 2}), DataType(DataType::DE_FLOAT64));
+  std::shared_ptr<Tensor> t2;
+  Tensor::CreateEmpty(TensorShape({3, 2}), DataType(DataType::DE_FLOAT64), &t2);
   t2->Fill<double>(4.4);
   std::shared_ptr<CVTensor> ctv = CVTensor::AsCVTensor(t);
   ASSERT_EQ(t->GetBuffer(), nullptr);
@@ -326,6 +345,10 @@ TEST_F(MindDataTestTensorDE, CVTensorAs) {
   ASSERT_EQ(ctv->GetBuffer(), addr);
   ASSERT_TRUE(*t2 == *ctv);
   MS_LOG(DEBUG) << *t2 << std::endl << *ctv;
+  cv::Mat m2 = ctv->matCopy();
+  m2 = 2 * m2;
+  ASSERT_EQ(ctv->GetBuffer(), addr);
+  ASSERT_TRUE(*t2 == *ctv);
 }
 
 TEST_F(MindDataTestTensorDE, CVTensorMatSlice) {
@@ -336,23 +359,26 @@ TEST_F(MindDataTestTensorDE, CVTensorMatSlice) {
   m.at<int32_t>(1, 0) = 40;
   m.at<int32_t>(1, 1) = 50;
   m.at<int32_t>(1, 2) = 60;
-  std::shared_ptr<CVTensor> cvt = std::make_shared<CVTensor>(m);
+  std::shared_ptr<CVTensor> cvt;
+  CVTensor::CreateFromMat(m, &cvt);
   cv::Mat mat;
-  cvt->Mat({1}, &mat);
+  cvt->MatAtIndex({1}, &mat);
   cv::Mat m2(3, 1, CV_32S);
   m2.at<int32_t>(0) = 40;
   m2.at<int32_t>(1) = 50;
   m2.at<int32_t>(2) = 60;
-  std::shared_ptr<CVTensor> cvt2 = std::make_shared<CVTensor>(mat);
+  std::shared_ptr<CVTensor> cvt2;
-  std::shared_ptr<CVTensor> cvt3 = std::make_shared<CVTensor>(m2);
+  CVTensor::CreateFromMat(mat, &cvt2);
+  std::shared_ptr<CVTensor> cvt3;
+  CVTensor::CreateFromMat(m2, &cvt3);
 
   ASSERT_TRUE(*cvt2 == *cvt3);
-  cvt->Mat({0}, &mat);
+  cvt->MatAtIndex({0}, &mat);
   m2.at<int32_t>(0) = 10;
   m2.at<int32_t>(1) = 20;
   m2.at<int32_t>(2) = 30;
-  cvt2 = std::make_shared<CVTensor>(mat);
+  CVTensor::CreateFromMat(mat, &cvt2);
-  cvt3 = std::make_shared<CVTensor>(m2);
+  CVTensor::CreateFromMat(m2, &cvt3);
   ASSERT_TRUE(*cvt2 == *cvt3);
 }
 
@@ -361,7 +387,7 @@ TEST_F(MindDataTestTensorDE, TensorIterator) {
   std::vector<uint32_t> values2 = {2, 3, 4, 5, 6, 7};
 
   std::shared_ptr<Tensor> t;
-  Tensor::CreateTensor(&t, values);
+  Tensor::CreateFromVector(values, &t);
 
   auto i = t->begin<uint32_t>();
   auto j = values.begin();
@@ -395,11 +421,11 @@ TEST_F(MindDataTestTensorDE, TensorIterator) {
 
 TEST_F(MindDataTestTensorDE, TensorSlice) {
   std::shared_ptr<Tensor> t;
-  Tensor::CreateTensor(&t, std::vector<dsize_t>{0, 1, 2, 3, 4});
+  Tensor::CreateFromVector(std::vector<dsize_t>{0, 1, 2, 3, 4}, &t);
   std::shared_ptr<Tensor> t2;
   auto x = std::vector<dsize_t>{0, 3, 4};
   std::shared_ptr<Tensor> expected;
-  Tensor::CreateTensor(&expected, x);
+  Tensor::CreateFromVector(x, &expected);
   t->Slice(&t2, x);
   ASSERT_EQ(*t2, *expected);
   t->Slice(&t2, std::vector<dsize_t>{0, 1, 2, 3, 4});
@@ -412,13 +438,13 @@ TEST_F(MindDataTestTensorDE, TensorConcatenate) {
   std::vector<uint32_t> expected = {1, 2, 3, 4, 5, 6};
 
   std::shared_ptr<Tensor> t1;
-  Tensor::CreateTensor(&t1, values1);
+  Tensor::CreateFromVector(values1, &t1);
 
   std::shared_ptr<Tensor> t2;
-  Tensor::CreateTensor(&t2, values2);
+  Tensor::CreateFromVector(values2, &t2);
 
   std::shared_ptr<Tensor> out;
-  Tensor::CreateTensor(&out, expected);
+  Tensor::CreateFromVector(expected, &out);
   Status s = t1->Concatenate({3}, t2);
   EXPECT_TRUE(s.IsOk());
 
@@ -434,15 +460,80 @@ TEST_F(MindDataTestTensorDE, TensorConcatenate) {
 }
 
 TEST_F(MindDataTestTensorDE, TensorEmpty) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({2, 3}), DataType(DataType::DE_UINT64));
+  TensorPtr t;
-  ASSERT_TRUE(t->HasData());
+  Status rc = Tensor::CreateEmpty(TensorShape({0}), DataType(DataType::DE_UINT64), &t);
-}
+  ASSERT_TRUE(rc.IsOk());
 
-TEST_F(MindDataTestTensorDE, TensorEmptyInvalidate) {
+  ASSERT_EQ(t->shape(), TensorShape({0}));
-  std::vector<uint32_t> values1 = {1, 2, 3, 0, 0, 0};
+  ASSERT_EQ(t->type(), DataType::DE_UINT64);
-  std::shared_ptr<Tensor> t;
+  ASSERT_EQ(t->SizeInBytes(), 0);
-  Tensor::CreateTensor(&t, values1);
+  ASSERT_EQ(t->GetBuffer(), nullptr);
-  t->Invalidate();
+  ASSERT_TRUE(!t->HasData());
-  ASSERT_TRUE(t->HasData());
-}
 
+  rc = t->SetItemAt<uint64_t>({0}, 7);
+  ASSERT_TRUE(rc.IsError());
+
+  rc = Tensor::CreateEmpty(TensorShape({1, 0}), DataType(DataType::DE_STRING), &t);
+  ASSERT_TRUE(rc.IsOk());
+  ASSERT_EQ(t->shape(), TensorShape({1, 0}));
+  ASSERT_EQ(t->type(), DataType::DE_STRING);
+  ASSERT_EQ(t->SizeInBytes(), 0);
+  ASSERT_EQ(t->GetBuffer(), nullptr);
+  ASSERT_TRUE(!t->HasData());
+
+  std::vector<uint16_t> data;
+  rc = Tensor::CreateFromVector(data, &t);
+  ASSERT_TRUE(rc.IsOk());
+  ASSERT_EQ(t->shape(), TensorShape({0}));
+  ASSERT_EQ(t->type(), DataType::DE_UINT16);
+  ASSERT_EQ(t->SizeInBytes(), 0);
+  ASSERT_EQ(t->GetBuffer(), nullptr);
+  ASSERT_TRUE(!t->HasData());
+
+  std::vector<std::string> data2;
+  rc = Tensor::CreateFromVector(data2, &t);
+  ASSERT_TRUE(rc.IsOk());
+  ASSERT_EQ(t->shape(), TensorShape({0}));
+  ASSERT_EQ(t->type(), DataType::DE_STRING);
+  ASSERT_EQ(t->SizeInBytes(), 0);
+  ASSERT_EQ(t->GetBuffer(), nullptr);
+  ASSERT_TRUE(!t->HasData());
+
+  rc = Tensor::CreateFromVector(data, TensorShape({0, 2}), &t);
+  ASSERT_TRUE(rc.IsOk());
+  ASSERT_EQ(t->shape(), TensorShape({0, 2}));
+  ASSERT_EQ(t->type(), DataType::DE_UINT16);
+  ASSERT_EQ(t->SizeInBytes(), 0);
+  ASSERT_EQ(t->GetBuffer(), nullptr);
+  ASSERT_TRUE(!t->HasData());
+
+  rc = Tensor::CreateFromVector(data2, TensorShape({0, 0, 6}), &t);
+  ASSERT_TRUE(rc.IsOk());
+  ASSERT_EQ(t->shape(), TensorShape({0, 0, 6}));
+  ASSERT_EQ(t->type(), DataType::DE_STRING);
+  ASSERT_EQ(t->SizeInBytes(), 0);
+  ASSERT_EQ(t->GetBuffer(), nullptr);
+  ASSERT_TRUE(!t->HasData());
+
+  rc = Tensor::CreateFromMemory(TensorShape({0}), DataType(DataType::DE_INT8), nullptr, &t);
+  ASSERT_TRUE(rc.IsOk());
+  ASSERT_EQ(t->shape(), TensorShape({0}));
+  ASSERT_EQ(t->type(), DataType::DE_INT8);
+  ASSERT_EQ(t->SizeInBytes(), 0);
+  ASSERT_EQ(t->GetBuffer(), nullptr);
+  ASSERT_TRUE(!t->HasData());
+
+  rc = Tensor::CreateFromMemory(TensorShape({0}), DataType(DataType::DE_STRING), nullptr, &t);
+  ASSERT_TRUE(rc.IsOk());
+  ASSERT_EQ(t->shape(), TensorShape({0}));
+  ASSERT_EQ(t->type(), DataType::DE_STRING);
+  ASSERT_EQ(t->SizeInBytes(), 0);
+  ASSERT_EQ(t->GetBuffer(), nullptr);
+
+  std::vector<uint32_t> values = {1, 2, 3, 0, 0, 0};
+  std::shared_ptr<Tensor> t2;
+  Tensor::CreateFromVector(values, &t2);
+  ASSERT_TRUE(t2->HasData());
+  t2->Invalidate();
+  ASSERT_TRUE(!t2->HasData());
+}

tests/ut/cpp/dataset/tokenizer_op_test.cc

@@ -46,8 +46,8 @@ class MindDataTestTokenizerOp : public UT::Common {
 TEST_F(MindDataTestTokenizerOp, TestUnicodeCharTokenizerOp) {
   MS_LOG(INFO) << "Doing TestUnicodeCharTokenizerOp.";
   std::unique_ptr<UnicodeCharTokenizerOp> op(new UnicodeCharTokenizerOp(true));
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>("Hello World!");
+std::shared_ptr<Tensor> input;
-  TensorRow output;
+  Tensor::CreateScalar<std::string>("Hello World!", &input);  TensorRow output;
   Status s = op->Compute(TensorRow(0, {input}), &output);
   EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 12);
@@ -66,7 +66,7 @@ TEST_F(MindDataTestTokenizerOp, TestUnicodeCharTokenizerOp) {
   CheckEqual(output[0], {10}, "d");
   CheckEqual(output[0], {11}, "!");
 
-  input = std::make_shared<Tensor>("中国 你好!");
+  Tensor::CreateScalar<std::string>("中国 你好!", &input);
   output.clear();
   s = op->Compute(TensorRow(0, {input}), &output);
   EXPECT_TRUE(s.IsOk());
@@ -80,38 +80,38 @@ TEST_F(MindDataTestTokenizerOp, TestUnicodeCharTokenizerOp) {
   CheckEqual(output[0], {4}, "好");
   CheckEqual(output[0], {5}, "!");
 
-  input = std::make_shared<Tensor>("中");
+  Tensor::CreateScalar<std::string>("中", &input);
-  output.clear();
+output.clear();
   s = op->Compute(TensorRow(0, {input}), &output);
-  EXPECT_TRUE(s.IsOk());
+    EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 1);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor3: " << output[0]->ToString();
   CheckEqual(output[0], {0}, "中");
 
-  input = std::make_shared<Tensor>("H");
+  Tensor::CreateScalar<std::string>("H", &input);
-  output.clear();
+output.clear();
   s = op->Compute(TensorRow(0, {input}), &output);
-  EXPECT_TRUE(s.IsOk());
+    EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 1);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor4: " << output[0]->ToString();
   CheckEqual(output[0], {0}, "H");
 
-  input = std::make_shared<Tensor>("  ");
+  Tensor::CreateScalar<std::string>("  ", &input);
-  output.clear();
+output.clear();
   s = op->Compute(TensorRow(0, {input}), &output);
-  EXPECT_TRUE(s.IsOk());
+    EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 2);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor5: " << output[0]->ToString();
   CheckEqual(output[0], {0}, " ");
   CheckEqual(output[0], {1}, " ");
 
-  input = std::make_shared<Tensor>("");
+  Tensor::CreateScalar<std::string>("", &input);
-  output.clear();
+output.clear();
   s = op->Compute(TensorRow(0, {input}), &output);
-  EXPECT_TRUE(s.IsOk());
+    EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 1);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor6: " << output[0]->ToString();
@@ -121,10 +121,10 @@ TEST_F(MindDataTestTokenizerOp, TestUnicodeCharTokenizerOp) {
 TEST_F(MindDataTestTokenizerOp, TestWhitespaceTokenizerOp) {
   MS_LOG(INFO) << "Doing TestWhitespaceTokenizerOp.";
   std::unique_ptr<WhitespaceTokenizerOp> op(new WhitespaceTokenizerOp(true));
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>("Welcome to China.");
+std::shared_ptr<Tensor> input;
-  TensorRow output;
+  Tensor::CreateScalar<std::string>("Welcome to China.", &input);  TensorRow output;
   Status s = op->Compute(TensorRow(0, {input}), &output);
-  EXPECT_TRUE(s.IsOk());
+    EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 3);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor1: " << output[0]->ToString();
@@ -132,37 +132,37 @@ TEST_F(MindDataTestTokenizerOp, TestWhitespaceTokenizerOp) {
   CheckEqual(output[0], {1}, "to");
   CheckEqual(output[0], {2}, "China.");
 
-  input = std::make_shared<Tensor>("  hello");
+  Tensor::CreateScalar<std::string>("  hello", &input);
-  output.clear();
+output.clear();
   s = op->Compute(TensorRow(0, {input}), &output);
-  EXPECT_TRUE(s.IsOk());
+    EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 1);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor2: " << output[0]->ToString();
   CheckEqual(output[0], {0}, "hello");
 
-  input = std::make_shared<Tensor>("hello");
+  Tensor::CreateScalar<std::string>("hello", &input);
-  output.clear();
+output.clear();
   s = op->Compute(TensorRow(0, {input}), &output);
-  EXPECT_TRUE(s.IsOk());
+    EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 1);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor3: " << output[0]->ToString();
   CheckEqual(output[0], {0}, "hello");
 
-  input = std::make_shared<Tensor>("hello  ");
+  Tensor::CreateScalar<std::string>("hello  ", &input);
-  output.clear();
+output.clear();
   s = op->Compute(TensorRow(0, {input}), &output);
-  EXPECT_TRUE(s.IsOk());
+    EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 1);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor4: " << output[0]->ToString();
   CheckEqual(output[0], {0}, "hello");
 
-  input = std::make_shared<Tensor>("  ");
+  Tensor::CreateScalar<std::string>("  ", &input);
-  output.clear();
+output.clear();
   s = op->Compute(TensorRow(0, {input}), &output);
-  EXPECT_TRUE(s.IsOk());
+    EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 1);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor5: " << output[0]->ToString();
@@ -174,8 +174,9 @@ TEST_F(MindDataTestTokenizerOp, TestUnicodeScriptTokenizer) {
   std::unique_ptr<UnicodeScriptTokenizerOp> keep_whitespace_op(new UnicodeScriptTokenizerOp(true, true));
   std::unique_ptr<UnicodeScriptTokenizerOp> skip_whitespace_op(new UnicodeScriptTokenizerOp(false, true));
 
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>("Welcome to China. \n 中国\t北京");
+ std::shared_ptr<Tensor> input;
-  TensorRow output;
+  Tensor::CreateScalar<std::string>("Welcome to China. \n 中国\t北京", &input);
+ TensorRow output;
   Status s = keep_whitespace_op->Compute(TensorRow(0, {input}), &output);
   EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 10);
@@ -204,10 +205,9 @@ TEST_F(MindDataTestTokenizerOp, TestUnicodeScriptTokenizer) {
   CheckEqual(output[0], {4}, "中国");
   CheckEqual(output[0], {5}, "北京");
 
-  input = std::make_shared<Tensor>("  Welcome to 中国.  ");
+  Tensor::CreateScalar<std::string>("  Welcome to 中国.  ", &input);
-  output.clear();
+ output.clear();
-  s = skip_whitespace_op->Compute(TensorRow(0, {input}), &output);
+  s = skip_whitespace_op->Compute(TensorRow(0, {input}), &output);  EXPECT_TRUE(s.IsOk());
-  EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 4);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor3: " << output[0]->ToString();
@@ -230,25 +230,23 @@ TEST_F(MindDataTestTokenizerOp, TestUnicodeScriptTokenizer) {
   CheckEqual(output[0], {6}, ".");
   CheckEqual(output[0], {7}, "  ");
 
-  input = std::make_shared<Tensor>("Hello");
+  Tensor::CreateScalar<std::string>("Hello", &input);
-  output.clear();
+output.clear();
-  s = keep_whitespace_op->Compute(TensorRow(0, {input}), &output);
+  s = keep_whitespace_op->Compute(TensorRow(0, {input}), &output);  EXPECT_TRUE(s.IsOk());
-  EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 1);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor5: " << output[0]->ToString();
   CheckEqual(output[0], {0}, "Hello");
 
-  input = std::make_shared<Tensor>("H");
+  Tensor::CreateScalar<std::string>("H", &input);
-  output.clear();
+output.clear();
-  s = keep_whitespace_op->Compute(TensorRow(0, {input}), &output);
+  s = keep_whitespace_op->Compute(TensorRow(0, {input}), &output);  EXPECT_TRUE(s.IsOk());
-  EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 1);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor6: " << output[0]->ToString();
   CheckEqual(output[0], {0}, "H");
 
-  input = std::make_shared<Tensor>("");
+  Tensor::CreateScalar<std::string>("", &input);
   output.clear();
   s = keep_whitespace_op->Compute(TensorRow(0, {input}), &output);
   EXPECT_TRUE(s.IsOk());
@@ -257,10 +255,9 @@ TEST_F(MindDataTestTokenizerOp, TestUnicodeScriptTokenizer) {
   MS_LOG(INFO) << "Out tensor7: " << output[0]->ToString();
   CheckEqual(output[0], {0}, "");
 
-  input = std::make_shared<Tensor>("Hello中国Hello世界");
+  Tensor::CreateScalar<std::string>("Hello中国Hello世界", &input);
-  output.clear();
+ output.clear();
-  s = keep_whitespace_op->Compute(TensorRow(0, {input}), &output); EXPECT_TRUE(s.IsOk());
+  s = keep_whitespace_op->Compute(TensorRow(0, {input}), &output); EXPECT_TRUE(s.IsOk());  EXPECT_EQ(output[0]->Size(), 4);
-  EXPECT_EQ(output[0]->Size(), 4);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor8: " << output[0]->ToString();
   CheckEqual(output[0], {0}, "Hello");
@@ -268,15 +265,15 @@ TEST_F(MindDataTestTokenizerOp, TestUnicodeScriptTokenizer) {
   CheckEqual(output[0], {2}, "Hello");
   CheckEqual(output[0], {3}, "世界");
 
-  input = std::make_shared<Tensor>("   ");
+  Tensor::CreateScalar<std::string>("   ", &input);
-  output.clear();
+ output.clear();
   s = keep_whitespace_op->Compute(TensorRow(0, {input}), &output);
-  EXPECT_TRUE(s.IsOk());
+   EXPECT_TRUE(s.IsOk());
   EXPECT_EQ(output[0]->Size(), 1);
   EXPECT_EQ(output[0]->Rank(), 1);
   MS_LOG(INFO) << "Out tensor10: " << output[0]->ToString();
   CheckEqual(output[0], {0}, "   ");
-  input = std::make_shared<Tensor>("   ");
+  Tensor::CreateScalar<std::string>("   ", &input);
   output.clear();
   s = skip_whitespace_op->Compute(TensorRow(0, {input}), &output);
   EXPECT_TRUE(s.IsOk());
@@ -289,7 +286,9 @@ TEST_F(MindDataTestTokenizerOp, TestUnicodeScriptTokenizer) {
 TEST_F(MindDataTestTokenizerOp, TestCaseFold) {
   MS_LOG(INFO) << "Doing TestCaseFold.";
   std::unique_ptr<CaseFoldOp> case_fold_op(new CaseFoldOp());
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>("Welcome to China. \n 中国\t北京");
+  std::shared_ptr<Tensor> input;
+  Tensor::CreateScalar<std::string>("Welcome to China. \n 中国\t北京", &input);
+
   std::shared_ptr<Tensor> output;
   Status s = case_fold_op->Compute(input, &output);
   EXPECT_TRUE(s.IsOk());
@@ -305,7 +304,8 @@ TEST_F(MindDataTestTokenizerOp, TestNormalize) {
   std::unique_ptr<NormalizeUTF8Op> nfkc_normalize_op(new NormalizeUTF8Op(NormalizeForm::kNfkc));
   std::unique_ptr<NormalizeUTF8Op> nfd_normalize_op(new NormalizeUTF8Op(NormalizeForm::kNfd));
   std::unique_ptr<NormalizeUTF8Op> nfkd_normalize_op(new NormalizeUTF8Op(NormalizeForm::kNfkd));
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>("ṩ");
+  std::shared_ptr<Tensor> input;
+  Tensor::CreateScalar<std::string>("ṩ", &input);
   std::shared_ptr<Tensor> output;
   Status s = nfc_normalize_op->Compute(input, &output);
   EXPECT_TRUE(s.IsOk());
@@ -327,7 +327,8 @@ TEST_F(MindDataTestTokenizerOp, TestNormalize) {
 TEST_F(MindDataTestTokenizerOp, TestRegexReplace) {
   MS_LOG(INFO) << "Doing TestRegexReplace.";
   std::unique_ptr<RegexReplaceOp> regex_replace_op(new RegexReplaceOp("\\s+", "_", true));
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>("Welcome to China. \n 中国\t北京");
+  std::shared_ptr<Tensor> input;
+  Tensor::CreateScalar<std::string>("Welcome to China. \n 中国\t北京", &input);
   std::shared_ptr<Tensor> output;
   Status s = regex_replace_op->Compute(input, &output);
   EXPECT_TRUE(s.IsOk());
@@ -340,19 +341,20 @@ TEST_F(MindDataTestTokenizerOp, TestRegexReplace) {
 TEST_F(MindDataTestTokenizerOp, TestRegexTokenizer) {
   MS_LOG(INFO) << "Doing TestRegexTokenizerOp.";
   std::unique_ptr<RegexTokenizerOp> regex_tokenizer_op(new RegexTokenizerOp("\\p{Cc}|\\p{Cf}|\\s+", "", true));
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>("Welcome to China. \n 中国\t北京");
+std::shared_ptr<Tensor> input;
-  TensorRow output;
+  Tensor::CreateScalar<std::string>("Welcome to China. \n 中国\t北京", &input);
+     TensorRow output;
   Status s = regex_tokenizer_op->Compute(TensorRow(0, {input}), &output);
   EXPECT_TRUE(s.IsOk());
 }
 
 TEST_F(MindDataTestTokenizerOp, TestBasicTokenizer) {
   MS_LOG(INFO) << "Doing TestBasicTokenizer.";
-  //bool lower_case, bool keep_whitespace, 
+  // bool lower_case, bool keep_whitespace,
   // NormalizeForm  normalization_form, bool preserve_unused_token
-  std::unique_ptr<BasicTokenizerOp> basic_tokenizer(new BasicTokenizerOp(true, true, NormalizeForm::kNone, false,
+  std::unique_ptr<BasicTokenizerOp> basic_tokenizer(new BasicTokenizerOp(true, true, NormalizeForm::kNone, false,true));
-                                                                         true));
+std::shared_ptr<Tensor> input;
-  std::shared_ptr<Tensor> input = std::make_shared<Tensor>("Welcome to China. 中国\t北京");
+  Tensor::CreateScalar<std::string>("Welcome to China. 中国\t北京", &input);
   TensorRow output;
   Status s = basic_tokenizer->Compute(TensorRow(0, {input}), &output);
   EXPECT_TRUE(s.IsOk());

tests/ut/cpp/dataset/trucate_pair_test.cc

@@ -35,17 +35,17 @@ class MindDataTestTruncatePairOp : public UT::Common {
 
 TEST_F(MindDataTestTruncatePairOp, Basics) {
   std::shared_ptr<Tensor> t1;
-  Tensor::CreateTensor(&t1, std::vector<uint32_t>({1, 2, 3}));
+  Tensor::CreateFromVector(std::vector<uint32_t>({1, 2, 3}), &t1);
   std::shared_ptr<Tensor> t2;
-  Tensor::CreateTensor(&t2, std::vector<uint32_t>({4, 5}));
+  Tensor::CreateFromVector(std::vector<uint32_t>({4, 5}), &t2);
   TensorRow in({t1, t2});
   std::shared_ptr<TruncateSequencePairOp> op = std::make_shared<TruncateSequencePairOp>(4);
   TensorRow out;
   ASSERT_TRUE(op->Compute(in, &out).IsOk());
   std::shared_ptr<Tensor> out1;
-  Tensor::CreateTensor(&out1, std::vector<uint32_t>({1, 2}));
+  Tensor::CreateFromVector(std::vector<uint32_t>({1, 2}), &out1);
   std::shared_ptr<Tensor> out2;
-  Tensor::CreateTensor(&out2, std::vector<uint32_t>({4, 5}));
+  Tensor::CreateFromVector(std::vector<uint32_t>({4, 5}), &out2);
   ASSERT_EQ(*out1, *out[0]);
   ASSERT_EQ(*out2, *out[1]);
 }

tests/ut/cpp/dataset/type_cast_op_test.cc

@@ -43,16 +43,15 @@ class MindDataTestTypeCast : public UT::Common {
 
 template<typename FROM, typename TO>
 void testCast(std::vector<FROM> values, const DataType &from, const DataType &to) {
-  std::shared_ptr<Tensor> t = std::make_shared<Tensor>(TensorShape({static_cast<int64_t>(values.size())}),
+  std::shared_ptr<Tensor> t;
-                                                       DataType(from),
+  Tensor::CreateFromVector(values, &t);
-                                                       reinterpret_cast<unsigned char *>(&values[0]));
 
   std::unique_ptr<TypeCastOp> op(new TypeCastOp(to));
   EXPECT_TRUE(op->OneToOne());
   std::shared_ptr<Tensor> output;
   EXPECT_TRUE(op->Compute(t, &output));
   ASSERT_TRUE(t->shape() == output->shape());
-  ASSERT_TRUE(DataType(to)==output->type());
+  ASSERT_TRUE(DataType(to) == output->type());
   MS_LOG(DEBUG) << *output << std::endl;
   auto out = output->begin<TO>();
   auto v = values.begin();

tests/ut/python/dataset/test_pair_truncate.py

@@ -16,7 +16,6 @@
 Testing Mask op in DE
 """
 import numpy as np
-import pytest
 
 import mindspore.dataset as ds
 import mindspore.dataset.text as text
@@ -55,9 +54,7 @@ def test_basics_str():
 
 
 def test_exceptions():
-    with pytest.raises(RuntimeError) as info:
+    compare(in1=[1, 2, 3, 4], in2=[5, 6, 7, 8], length=1, out1=[1], out2=[])
-        compare(in1=[1, 2, 3, 4], in2=[5, 6, 7, 8], length=1, out1=[1, 2], out2=[5])
-    assert "Indices are empty, generated tensor would be empty" in str(info.value)
 
 
 if __name__ == "__main__":

tests/ut/python/dataset/test_slice_op.py

@@ -121,21 +121,10 @@ def test_slice_exceptions():
         slice_compare([1, 2, 3, 4, 5], 5)
     assert "Index 5 is out of bounds [0,5)" in str(info.value)
 
-    with pytest.raises(RuntimeError) as info:
+    slice_compare([1, 2, 3, 4, 5], slice(0))
-        slice_compare([1, 2, 3, 4, 5], slice(0))
+    slice_compare([1, 2, 3, 4, 5], slice(3, 1, 1))
-    assert "Indices are empty, generated tensor would be empty." in str(info.value)
+    slice_compare([1, 2, 3, 4, 5], slice(5, 10, 1))
-
+    slice_compare([1, 2, 3, 4, 5], slice(-1, -5, 1))
-    with pytest.raises(RuntimeError) as info:
-        slice_compare([1, 2, 3, 4, 5], slice(3, 1, 1))
-    assert "Indices are empty, generated tensor would be empty." in str(info.value)
-
-    with pytest.raises(RuntimeError) as info:
-        slice_compare([1, 2, 3, 4, 5], slice(5, 10, 1))
-    assert "Indices are empty, generated tensor would be empty." in str(info.value)
-
-    with pytest.raises(RuntimeError) as info:
-        slice_compare([1, 2, 3, 4, 5], slice(-1, -5, 1))
-    assert "Indices are empty, generated tensor would be empty." in str(info.value)
 
 
 def test_slice_all_str():
@@ -198,21 +187,10 @@ def test_slice_exceptions_str():
         slice_compare([b"1", b"2", b"3", b"4", b"5"], 5)
     assert "Index 5 is out of bounds [0,5)" in str(info.value)
 
-    with pytest.raises(RuntimeError) as info:
+    slice_compare([b"1", b"2", b"3", b"4", b"5"], slice(0))
-        slice_compare([b"1", b"2", b"3", b"4", b"5"], slice(0))
+    slice_compare([b"1", b"2", b"3", b"4", b"5"], slice(3, 1, 1))
-    assert "Indices are empty, generated tensor would be empty." in str(info.value)
+    slice_compare([b"1", b"2", b"3", b"4", b"5"], slice(5, 10, 1))
-
+    slice_compare([b"1", b"2", b"3", b"4", b"5"], slice(-1, -5, 1))
-    with pytest.raises(RuntimeError) as info:
-        slice_compare([b"1", b"2", b"3", b"4", b"5"], slice(3, 1, 1))
-    assert "Indices are empty, generated tensor would be empty." in str(info.value)
-
-    with pytest.raises(RuntimeError) as info:
-        slice_compare([b"1", b"2", b"3", b"4", b"5"], slice(5, 10, 1))
-    assert "Indices are empty, generated tensor would be empty." in str(info.value)
-
-    with pytest.raises(RuntimeError) as info:
-        slice_compare([b"1", b"2", b"3", b"4", b"5"], slice(-1, -5, 1))
-    assert "Indices are empty, generated tensor would be empty." in str(info.value)
 
 
 if __name__ == "__main__":

tests/ut/python/dataset/test_tensor_empty.py

@@ -0,0 +1,72 @@
+# Copyright 2020 Huawei Technologies Co., Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+import numpy as np
+
+import mindspore.dataset as ds
+
+
+def test_tensor_empty():
+    def gen():
+        for _ in range(4):
+            (yield np.array([], dtype=np.int64), np.array([], dtype='S').reshape([0, 4]), np.array([1],
+                                                                                                   dtype=np.float64))
+
+    data = ds.GeneratorDataset(gen, column_names=["col1", "col2", "col3"])
+
+    for d in data:
+        np.testing.assert_array_equal(np.array([], dtype=np.int64), d[0])
+        np.testing.assert_array_equal(np.array([], dtype='S').reshape([0, 4]), d[1])
+        np.testing.assert_array_equal(np.array([1], dtype=np.float64), d[2])
+
+
+def test_tensor_empty_map():
+    def gen():
+        for _ in range(4):
+            (yield np.array([], dtype=np.int64), np.array([], dtype='S'), np.array([1], dtype=np.float64))
+
+    data = ds.GeneratorDataset(gen, column_names=["col1", "col2", "col3"])
+
+    def func(x, y, z):
+        x = np.array([1], dtype=np.int64)
+        y = np.array(["Hi"], dtype='S')
+        z = np.array([], dtype=np.float64)
+        return x, y, z
+
+    data = data.map(input_columns=["col1", "col2", "col3"], operations=func)
+
+    for d in data:
+        np.testing.assert_array_equal(np.array([1], dtype=np.int64), d[0])
+        np.testing.assert_array_equal(np.array(["Hi"], dtype='S'), d[1])
+        np.testing.assert_array_equal(np.array([], dtype=np.float64), d[2])
+
+
+def test_tensor_empty_batch():
+    def gen():
+        for _ in range(4):
+            (yield np.array([], dtype=np.int64), np.array([], dtype='S').reshape([0, 4]), np.array([1],
+                                                                                                   dtype=np.float64))
+
+    data = ds.GeneratorDataset(gen, column_names=["col1", "col2", "col3"]).batch(2)
+
+    for d in data:
+        np.testing.assert_array_equal(np.array([], dtype=np.int64).reshape([2, 0]), d[0])
+        np.testing.assert_array_equal(np.array([], dtype='S').reshape([2, 0, 4]), d[1])
+        np.testing.assert_array_equal(np.array([[1], [1]], dtype=np.float64), d[2])
+
+
+if __name__ == '__main__':
+    test_tensor_empty()
+    test_tensor_empty_map()
+    test_tensor_empty_batch()