Ifpack2_Details_MultiVectorLocalGatherScatter.hpp

Go to the documentation of this file.

/*@HEADER
// ***********************************************************************
//
//       Ifpack2: Tempated Object-Oriented Algebraic Preconditioner Package
//                 Copyright (2009) Sandia Corporation
//
// Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
// license for use of this work by or on behalf of the U.S. Government.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// 3. Neither the name of the Corporation nor the names of the
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY SANDIA CORPORATION "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SANDIA CORPORATION OR THE
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Questions? Contact Michael A. Heroux (maherou@sandia.gov)
//
// ***********************************************************************
//@HEADER
*/

#ifndef IFPACK2_DETAILS_MULTIVECTORLOCALGATHERSCATTER_HPP
#define IFPACK2_DETAILS_MULTIVECTORLOCALGATHERSCATTER_HPP


#include "Tpetra_MultiVector.hpp"
#include "Tpetra_Map.hpp"

namespace Ifpack2 {
namespace Details {

template<class MV_in, class MV_out>
class MultiVectorLocalGatherScatter {
public:
  void
  gather (MV_out& X_out,
          const MV_in& X_in,
          const Teuchos::ArrayView<const typename MV_in::local_ordinal_type>& perm) const
  {
    using Teuchos::ArrayRCP;
    const size_t numRows = X_out.getLocalLength ();
    const size_t numVecs = X_in.getNumVectors ();

    for (size_t j = 0; j < numVecs; ++j) {
      ArrayRCP<const typename MV_in::scalar_type> X_in_j = X_in.getData (j);
      ArrayRCP<typename MV_out::scalar_type> X_out_j = X_out.getDataNonConst (j);

      for (size_t i = 0; i < numRows; ++i) {
        const size_t i_perm = perm[i];
        X_out_j[i] = X_in_j[i_perm];
      }
    }
  }

  void
  scatter (MV_in& X_in,
           const MV_out& X_out,
           const Teuchos::ArrayView<const typename MV_in::local_ordinal_type>& perm) const
  {
    using Teuchos::ArrayRCP;
    const size_t numRows = X_out.getLocalLength ();
    const size_t numVecs = X_in.getNumVectors ();

    for (size_t j = 0; j < numVecs; ++j) {
      ArrayRCP<typename MV_in::scalar_type> X_in_j = X_in.getDataNonConst (j);
      ArrayRCP<const typename MV_out::scalar_type> X_out_j = X_out.getData (j);

      for (size_t i = 0; i < numRows; ++i) {
        const size_t i_perm = perm[i];
        X_in_j[i_perm] = X_out_j[i];
      }
    }
  }
};

} // namespace Details
} // namespace Ifpack2

#endif // IFPACK2_DETAILS_MULTIVECTORLOCALGATHERSCATTER_HPP