MultiVectorMinResSolver.h

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// This file is part of the DFT-FE code.
//
// The DFT-FE code is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE at
// the top level of the DFT-FE distribution.
//
// ---------------------------------------------------------------------
//
 
#ifndef DFTFE_MULTIVECTORMINRESSOLVER_H
#define DFTFE_MULTIVECTORMINRESSOLVER_H
 
#include "MultiVectorLinearSolverProblem.h"
#include "headers.h"
#include "BLASWrapper.h"
namespace dftfe
{
  /*
   * @brief The class provides the MinRES algorithm to solve Ax = b
   * where A is positive semi-definite matrix
   */
  class MultiVectorMinResSolver
  {
  public:
    MultiVectorMinResSolver(const MPI_Comm &mpi_comm_parent,
                            const MPI_Comm &mpi_comm_domain);
    template <dftfe::utils::MemorySpace memorySpace>
    void
    solve(MultiVectorLinearSolverProblem<memorySpace> &problem,
          std::shared_ptr<dftfe::linearAlgebra::BLASWrapper<memorySpace>>
            BLASWrapperPtr,
          dftfe::linearAlgebra::MultiVector<double, memorySpace> &xMemSpace,
          dftfe::linearAlgebra::MultiVector<double, memorySpace> &NDBCVec,
          dftfe::uInt                                             locallyOwned,
          dftfe::uInt                                             blockSize,
          const double                                            absTolerance,
          const dftfe::uInt maxNumberIterations,
          const dftfe::uInt debugLevel     = 0,
          bool              distributeFlag = true); // override;
 
  private:
    const MPI_Comm             mpi_communicator;
    const dftfe::uInt          n_mpi_processes;
    const dftfe::uInt          this_mpi_process;
    dealii::ConditionalOStream pcout;
  };
} // namespace dftfe
 
#endif // DFTFE_MULTIVECTORMINRESSOLVER_H