implemention of new api: apply

mindspore/dataset/engine/datasets.py

@@ -499,6 +499,51 @@ class Dataset:
 
         return ProjectDataset(self, columns)
 
+    def apply(self, apply_func):
+        """
+        Apply a function in this dataset.
+
+        The specified apply_func is a function that must take one 'Dataset' as an argument
+        and return a preprogressing 'Dataset'.
+
+        Args:
+            apply_func (function): A function that must take one 'Dataset' as an argument and
+                                   return a preprogressing 'Dataset'.
+
+        Returns:
+            Dataset, applied by the function.
+
+        Examples:
+            >>> import numpy as np
+            >>> import mindspore.dataset as ds
+            >>> # Generate 1d int numpy array from 0 - 6
+            >>> def generator_1d():
+            >>>     for i in range(6):
+            >>>         yield (np.array([i]),)
+            >>> # 1) get all data from dataset
+            >>> data = ds.GeneratorDataset(generator_1d, ["data"])
+            >>> # 2) declare a apply_func function
+            >>> def apply_func(ds):
+            >>>     ds = ds.batch(2)
+            >>>     return ds
+            >>> # 3) use apply to call apply_func
+            >>> data = data.apply(apply_func)
+            >>> for item in data.create_dict_iterator():
+            >>>     print(item["data"])
+
+        Raises:
+            TypeError: If apply_func is not a function.
+            TypeError: If apply_func doesn't return a Dataset.
+        """
+
+        if not hasattr(apply_func, '__call__'):
+            raise TypeError("apply_func must be a function.")
+
+        dataset = apply_func(self)
+        if not isinstance(dataset, Dataset):
+            raise TypeError("apply_func must return a dataset.")
+        return dataset
+
     def device_que(self, prefetch_size=None):
         """
         Returns a transferredDataset that transfer data through tdt.

tests/ut/python/dataset/test_apply.py

@@ -0,0 +1,236 @@
+# Copyright 2019 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 mindspore.dataset as ds
+from mindspore import log as logger
+import mindspore.dataset.transforms.vision.c_transforms as vision
+import numpy as np
+
+DATA_DIR = "../data/dataset/testPK/data"
+
+# Generate 1d int numpy array from 0 - 64
+def generator_1d():
+    for i in range(64):
+        yield (np.array([i]),)
+
+def test_apply_generator_case():
+    # apply dataset operations
+    data1 = ds.GeneratorDataset(generator_1d, ["data"])
+    data2 = ds.GeneratorDataset(generator_1d, ["data"])
+
+    def dataset_fn(ds):
+        ds = ds.repeat(2)
+        return ds.batch(4)
+
+    data1 = data1.apply(dataset_fn)
+    data2 = data2.repeat(2)
+    data2 = data2.batch(4)
+
+    for item1, item2 in zip(data1.create_dict_iterator(), data2.create_dict_iterator()):
+        assert np.array_equal(item1["data"], item2["data"])
+
+def test_apply_imagefolder_case():
+    # apply dataset map operations
+    data1 = ds.ImageFolderDatasetV2(DATA_DIR, num_shards=4, shard_id=3)
+    data2 = ds.ImageFolderDatasetV2(DATA_DIR, num_shards=4, shard_id=3)
+
+    decode_op = vision.Decode()
+    normalize_op = vision.Normalize([121.0, 115.0, 100.0], [70.0, 68.0, 71.0])
+
+    def dataset_fn(ds):
+        ds = ds.map(operations = decode_op)
+        ds = ds.map(operations = normalize_op)
+        ds = ds.repeat(2)
+        return ds
+    
+    data1 = data1.apply(dataset_fn)
+    data2 = data2.map(operations = decode_op)
+    data2 = data2.map(operations = normalize_op)
+    data2 = data2.repeat(2)
+    
+    for item1, item2 in zip(data1.create_dict_iterator(), data2.create_dict_iterator()):
+        assert np.array_equal(item1["image"], item2["image"])
+
+def test_apply_flow_case_0(id=0):
+    # apply control flow operations
+    data1 = ds.GeneratorDataset(generator_1d, ["data"])
+
+    def dataset_fn(ds):
+        if id == 0:
+            ds = ds.batch(4)
+        elif id == 1:
+            ds = ds.repeat(2)
+        elif id == 2:
+            ds = ds.batch(4)
+            ds = ds.repeat(2)
+        else:
+            ds = ds.shuffle(buffer_size=4)
+        return ds
+
+    data1 = data1.apply(dataset_fn)
+    num_iter = 0
+    for _ in data1.create_dict_iterator():
+        num_iter = num_iter + 1
+
+    if id == 0:
+        assert num_iter == 16
+    elif id == 1:
+        assert num_iter == 128
+    elif id == 2:
+        assert num_iter == 32
+    else:
+        assert num_iter == 64
+
+def test_apply_flow_case_1(id=1):
+    # apply control flow operations
+    data1 = ds.GeneratorDataset(generator_1d, ["data"])
+
+    def dataset_fn(ds):
+        if id == 0:
+            ds = ds.batch(4)
+        elif id == 1:
+            ds = ds.repeat(2)
+        elif id == 2:
+            ds = ds.batch(4)
+            ds = ds.repeat(2)
+        else:
+            ds = ds.shuffle(buffer_size=4)
+        return ds
+
+    data1 = data1.apply(dataset_fn)
+    num_iter = 0
+    for _ in data1.create_dict_iterator():
+        num_iter = num_iter + 1
+
+    if id == 0:
+        assert num_iter == 16
+    elif id == 1:
+        assert num_iter == 128
+    elif id == 2:
+        assert num_iter == 32
+    else:
+        assert num_iter == 64
+
+def test_apply_flow_case_2(id=2):
+    # apply control flow operations
+    data1 = ds.GeneratorDataset(generator_1d, ["data"])
+
+    def dataset_fn(ds):
+        if id == 0:
+            ds = ds.batch(4)
+        elif id == 1:
+            ds = ds.repeat(2)
+        elif id == 2:
+            ds = ds.batch(4)
+            ds = ds.repeat(2)
+        else:
+            ds = ds.shuffle(buffer_size=4)
+        return ds
+
+    data1 = data1.apply(dataset_fn)
+    num_iter = 0
+    for _ in data1.create_dict_iterator():
+        num_iter = num_iter + 1
+
+    if id == 0:
+        assert num_iter == 16
+    elif id == 1:
+        assert num_iter == 128
+    elif id == 2:
+        assert num_iter == 32
+    else:
+        assert num_iter == 64
+
+def test_apply_flow_case_3(id=3):
+    # apply control flow operations
+    data1 = ds.GeneratorDataset(generator_1d, ["data"])
+
+    def dataset_fn(ds):
+        if id == 0:
+            ds = ds.batch(4)
+        elif id == 1:
+            ds = ds.repeat(2)
+        elif id == 2:
+            ds = ds.batch(4)
+            ds = ds.repeat(2)
+        else:
+            ds = ds.shuffle(buffer_size=4)
+        return ds
+
+    data1 = data1.apply(dataset_fn)
+    num_iter = 0
+    for _ in data1.create_dict_iterator():
+        num_iter = num_iter + 1
+
+    if id == 0:
+        assert num_iter == 16
+    elif id == 1:
+        assert num_iter == 128
+    elif id == 2:
+        assert num_iter == 32
+    else:
+        assert num_iter == 64
+
+def test_apply_exception_case():
+    # apply exception operations
+    data1 = ds.GeneratorDataset(generator_1d, ["data"])
+
+    def dataset_fn(ds):
+        ds = ds.repeat(2)
+        return ds.batch(4)
+
+    def exception_fn(ds):
+        return np.array([[0], [1], [3], [4], [5]])
+
+    try:
+        data1 = data1.apply("123")
+        for _ in data1.create_dict_iterator():
+            pass
+        assert False
+    except TypeError:
+        pass
+
+    try:
+        data1 = data1.apply(exception_fn)
+        for _ in data1.create_dict_iterator():
+            pass
+        assert False
+    except TypeError:
+        pass
+
+    try:
+        data2 = data1.apply(dataset_fn)
+        data3 = data1.apply(dataset_fn)
+        for item1, item2 in zip(data1.create_dict_iterator(), data2.create_dict_iterator()):
+            pass
+        assert False
+    except ValueError:
+        pass
+ 
+if __name__ == '__main__':
+    logger.info("Running test_apply.py test_apply_generator_case() function")
+    test_apply_generator_case()
+
+    logger.info("Running test_apply.py test_apply_imagefolder_case() function")
+    test_apply_imagefolder_case()
+
+    logger.info("Running test_apply.py test_apply_flow_case(id) function")
+    test_apply_flow_case_0()
+    test_apply_flow_case_1()
+    test_apply_flow_case_2()
+    test_apply_flow_case_3()
+
+    logger.info("Running test_apply.py test_apply_exception_case() function")
+    test_apply_exception_case()
+