PreconditionerJacobi.h

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/******************************************************************************
 * Copyright (c) 2021.                                                        *
 * The Regents of the University of Michigan and DFT-EFE developers.          *
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 * This file is part of the DFT-EFE code.                                     *
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 * DFT-EFE is free software: you can redistribute it and/or modify            *
 *   it under the terms of the Lesser GNU General Public License as           *
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 *   See the Lesser GNU General Public License for more details.              *
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/*
 * @author Bikash Kanungo
 */
 
#ifndef dftefePreconditionerJacobi_h
#define dftefePreconditionerJacobi_h
 
#include <utils/MemorySpaceType.h>
#include <linearAlgebra/Preconditioner.h>
#include <linearAlgebra/Vector.h>
#include <linearAlgebra/MultiVector.h>
#include <linearAlgebra/LinearAlgebraTypes.h>
#include <linearAlgebra/BlasLapackTypedef.h>
namespace dftefe
{
  namespace linearAlgebra
  {
    template <typename ValueTypeOperator,
              typename ValueTypeOperand,
              utils::MemorySpace memorySpace>
    class PreconditionerJacobi
      : public Preconditioner<ValueTypeOperator, ValueTypeOperand, memorySpace>
    {
      //
      // typedefs
      //
    public:
      //
      // alias to define the union of ValueTypeOperator and ValueTypeOperand
      // (e.g., the union of double and complex<double> is complex<double>)
      //
      using ValueTypeUnion =
        blasLapack::scalar_type<ValueTypeOperator, ValueTypeOperand>;
 
    public:
      PreconditionerJacobi(
        const Vector<ValueTypeOperator, memorySpace> &diagonal);
 
      ~PreconditionerJacobi() = default;
 
      /*
       * @brief Function to apply the Jacobi preconditioner on an input Vector \p x
       * and store the output in \p y. That is, it stores \f$y_i=1/x_i$\f
       *
       * @param[in] x Input Vector
       * @param[out] y Output Vector
       *
       * @note The input Vector \p x can be modified inside the function for
       * performance reasons. If the user needs \p x to be constant
       * (un-modified), we suggest the user to make a copy of \p x
       * prior to calling this function
       *
       */
      // void
      // apply(Vector<ValueTypeOperand, memorySpace> &x,
      //       Vector<ValueTypeUnion, memorySpace> &  y) const override;
 
      /*
       * @brief Function to apply the Jacobi preconditioner on an input Vector \p X
       * and store the output in \p Y. That is, it stores \f$Y_i=1/X_i$\f
       *
       * @param[in] X Input Vector
       * @param[out] Y Output Vector
       *
       * @note The input Vector \p X can be modified inside the function for
       * performance reasons. If the user needs \p X to be constant
       * (un-modified), we suggest the user to make a copy of \p X
       * prior to calling this function
       *
       */
      void
      apply(MultiVector<ValueTypeOperand, memorySpace> &X,
            MultiVector<ValueTypeUnion, memorySpace> &  Y) const override;
 
      PreconditionerType
      getPreconditionerType() const override;
 
    private:
      Vector<ValueTypeOperator, memorySpace> d_diagonalInv;
      PreconditionerType                     d_pcType;
    };
 
 
  } // end of namespace linearAlgebra
} // end of namespace dftefe
#include <linearAlgebra/PreconditionerJacobi.t.cpp>
#endif // dftefePreconditionerJacobi_h