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//                        Kokkos v. 2.0
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#ifndef SPARSELINEARSYSTEM_CUDA_HPP
#define SPARSELINEARSYSTEM_CUDA_HPP

#if defined( BUILD_FROM_CU_FILE )

#include <cusparse_v2.h>
#include <Kokkos_Core.hpp>

namespace Kokkos {
namespace Impl {


struct CudaSparseSingleton {
  cusparseHandle_t   handle;
  cusparseMatDescr_t descra;

  CudaSparseSingleton()
  {
    cusparseCreate( & handle );
    cusparseCreateMatDescr( & descra );
    cusparseSetMatType(       descra , CUSPARSE_MATRIX_TYPE_GENERAL );
    cusparseSetMatIndexBase(  descra , CUSPARSE_INDEX_BASE_ZERO );
  }

  static CudaSparseSingleton & singleton();

};

CudaSparseSingleton & CudaSparseSingleton::singleton()
{ static CudaSparseSingleton s ; return s ; }


template<>
struct Multiply< CrsMatrix<double,Cuda> ,
                 View<double*,Cuda > ,
                 View<double*,Cuda > >
{
  typedef Cuda                                      execution_space ;
  typedef execution_space::size_type                    size_type ;
  typedef double                                    scalar_type ;
  typedef View< scalar_type* , execution_space >        vector_type ;
  typedef CrsMatrix< scalar_type , execution_space >    matrix_type ;

public:

  Multiply( const matrix_type & A ,
            const size_type nrow ,
            const size_type ncol ,
            const vector_type & x ,
            const vector_type & y )
  {
    CudaSparseSingleton & s = CudaSparseSingleton::singleton();
    const scalar_type alpha = 1 , beta = 0 ;

    cusparseStatus_t status =
      cusparseDcsrmv( s.handle ,
                      CUSPARSE_OPERATION_NON_TRANSPOSE ,
                      nrow , ncol , A.coefficients.dimension_0() ,
                      &alpha ,
                      s.descra ,
                      A.coefficients.ptr_on_device() ,
                      A.graph.row_map.ptr_on_device() ,
                      A.graph.entries.ptr_on_device() ,
                      x.ptr_on_device() ,
                      &beta ,
                      y.ptr_on_device() );

    if ( CUSPARSE_STATUS_SUCCESS != status ) {
      throw std::runtime_error( std::string("ERROR - cusparseDcsrmv " ) );
    }
  }
};


template<>
struct Multiply< CrsMatrix<float,Cuda> ,
                 View<float*,Cuda > ,
                 View<float*,Cuda > >
{
  typedef Cuda                                      execution_space ;
  typedef execution_space::size_type                    size_type ;
  typedef float                                     scalar_type ;
  typedef View< scalar_type* , execution_space >        vector_type ;
  typedef CrsMatrix< scalar_type , execution_space >    matrix_type ;

public:

  Multiply( const matrix_type & A ,
            const size_type nrow ,
            const size_type ncol ,
            const vector_type & x ,
            const vector_type & y )
  {
    CudaSparseSingleton & s = CudaSparseSingleton::singleton();
    const scalar_type alpha = 1 , beta = 0 ;

    cusparseStatus_t status =
      cusparseScsrmv( s.handle ,
                      CUSPARSE_OPERATION_NON_TRANSPOSE ,
                      nrow , ncol , A.coefficients.dimension_0() ,
                      &alpha ,
                      s.descra ,
                      A.coefficients.ptr_on_device() ,
                      A.graph.row_map.ptr_on_device() ,
                      A.graph.entries.ptr_on_device() ,
                      x.ptr_on_device() ,
                      &beta ,
                      y.ptr_on_device() );

    if ( CUSPARSE_STATUS_SUCCESS != status ) {
      throw std::runtime_error( std::string("ERROR - cusparseDcsrmv " ) );
    }
  }
};

} /* namespace Impl */
} /* namespace Kokkos */

#endif /* #if defined( __CUDACC__ ) */
#endif /* #ifndef SPARSELINEARSYSTEM_CUDA_HPP */

