jacobi_precond.hpp

// FEAT3: Finite Element Analysis Toolbox, Version 3
// Copyright (C) 2010 by Stefan Turek & the FEAT group
// FEAT3 is released under the GNU General Public License version 3,
// see the file 'copyright.txt' in the top level directory for details.
 
#pragma once
 
// includes, FEAT
#include <kernel/solver/base.hpp>
 
namespace FEAT
{
  namespace Solver
  {
    template<typename Matrix_, typename Filter_>
    class JacobiPrecond :
      public SolverBase<typename Matrix_::VectorTypeL>
    {
    public:
      typedef Matrix_ MatrixType;
      typedef Filter_ FilterType;
      typedef typename MatrixType::VectorTypeL VectorType;
      typedef typename MatrixType::DataType DataType;
      typedef SolverBase<VectorType> BaseClass;
 
    protected:
      const MatrixType& _matrix;
      const FilterType& _filter;
      DataType _omega;
      VectorType _inv_diag;
 
    public:
      explicit JacobiPrecond(const MatrixType& matrix, const FilterType& filter, DataType omega = DataType(1)) :
        _matrix(matrix),
        _filter(filter),
        _omega(omega)
      {
      }
 
      explicit JacobiPrecond(const String& section_name, const PropertyMap* section,
        const MatrixType& matrix, const FilterType& filter) :
        BaseClass(section_name, section),
        _matrix(matrix),
        _filter(filter),
        _omega(1)
      {
        auto omega_p = section->query("omega");
        if(omega_p.second && (!omega_p.first.parse(this->_omega) || (this->_omega <= DataType(0))))
          throw ParseError(section_name + ".omega", omega_p.first, "a positive float");
      }
 
      virtual ~JacobiPrecond()
      {
      }
 
      virtual String name() const override
      {
        return "Jacobi";
      }
 
      virtual void init_symbolic() override
      {
        _inv_diag = _matrix.create_vector_r();
      }
 
      virtual void done_symbolic() override
      {
        _inv_diag.clear();
      }
 
      virtual void init_numeric() override
      {
        // extract matrix diagonal
        _matrix.extract_diag(_inv_diag);
 
        // invert diagonal elements
        _inv_diag.component_invert(_inv_diag, _omega);
      }
 
      void set_omega(DataType omega)
      {
        XASSERT(omega > DataType(0));
        _omega = omega;
      }
 
      virtual Status apply(VectorType& vec_cor, const VectorType& vec_def) override
      {
        vec_cor.component_product(_inv_diag, vec_def);
        this->_filter.filter_cor(vec_cor);
        return Status::success;
      }
    }; // class JacobiPrecond<...>
 
    template<typename Matrix_, typename Filter_>
    inline std::shared_ptr<JacobiPrecond<Matrix_, Filter_>> new_jacobi_precond(
      const Matrix_& matrix, const Filter_& filter,
      const typename Matrix_::DataType omega = typename Matrix_::DataType(1))
    {
      return std::make_shared<JacobiPrecond<Matrix_, Filter_>>(matrix, filter, omega);
    }
 
    template<typename Matrix_, typename Filter_>
    inline std::shared_ptr<JacobiPrecond<Matrix_, Filter_>> new_jacobi_precond(
      const String& section_name, const PropertyMap* section,
      const Matrix_& matrix, const Filter_& filter)
    {
      return std::make_shared<JacobiPrecond<Matrix_, Filter_>>(section_name, section, matrix, filter);
    }
 
  } // namespace Solver
} // namespace FEAT