petsc_linear_solver.h

Go to the documentation of this file.

// The libMesh Finite Element Library.
// Copyright (C) 2002-2019 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
 
// This library is free software; you can 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.
 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
 
 
#ifndef LIBMESH_PETSC_LINEAR_SOLVER_H
#define LIBMESH_PETSC_LINEAR_SOLVER_H
 
#include "libmesh/libmesh_config.h"
 
#ifdef LIBMESH_HAVE_PETSC
 
#include "libmesh/petsc_macro.h"
#include "libmesh/petsc_solver_exception.h"
 
// Petsc include files.
#ifdef I
# define LIBMESH_SAW_I
#endif
#include <petscksp.h>
#ifndef LIBMESH_SAW_I
# undef I // Avoid complex.h contamination
#endif
 
// Local includes
#include "libmesh/linear_solver.h"
 
// C++ includes
#include <cstddef>
#include <vector>
 
//--------------------------------------------------------------------
// Functions with C linkage to pass to PETSc.  PETSc will call these
// methods as needed for preconditioning
//
// Since they must have C linkage they have no knowledge of a namespace.
// Give them an obscure name to avoid namespace pollution.
extern "C"
{
#if PETSC_RELEASE_LESS_THAN(3,0,1)
 
  PetscErrorCode libmesh_petsc_preconditioner_setup (void * ctx);
 
  PetscErrorCode libmesh_petsc_preconditioner_apply(void * ctx, Vec x, Vec y);
#else
  PetscErrorCode libmesh_petsc_preconditioner_setup (PC);
  PetscErrorCode libmesh_petsc_preconditioner_apply(PC, Vec x, Vec y);
#endif
 
#if LIBMESH_ENABLE_DEPRECATED
#if PETSC_RELEASE_LESS_THAN(3,0,1)
 
  PetscErrorCode __libmesh_petsc_preconditioner_setup (void * ctx);
 
  PetscErrorCode __libmesh_petsc_preconditioner_apply(void * ctx, Vec x, Vec y);
#else
  PetscErrorCode __libmesh_petsc_preconditioner_setup (PC);
  PetscErrorCode __libmesh_petsc_preconditioner_apply(PC, Vec x, Vec y);
#endif
#endif
} // end extern "C"
 
 
namespace libMesh
{
 
// forward declarations
template <typename T> class PetscMatrix;
 
template <typename T>
class PetscLinearSolver : public LinearSolver<T>
{
public:
  PetscLinearSolver (const libMesh::Parallel::Communicator & comm_in);
 
  ~PetscLinearSolver ();
 
  virtual void clear () override;
 
  virtual void init (const char * name = nullptr) override;
 
  void init (PetscMatrix<T> * matrix,
             const char * name = nullptr);
 
  virtual void init_names (const System &) override;
 
  virtual void restrict_solve_to (const std::vector<unsigned int> * const dofs,
                                  const SubsetSolveMode subset_solve_mode=SUBSET_ZERO) override;
 
  virtual std::pair<unsigned int, Real>
  solve (SparseMatrix<T> & matrix_in,
         NumericVector<T> & solution_in,
         NumericVector<T> & rhs_in,
         const double tol,
         const unsigned int m_its) override
  {
    return this->solve(matrix_in, matrix_in, solution_in, rhs_in, tol, m_its);
  }
 
 
  virtual std::pair<unsigned int, Real>
  adjoint_solve (SparseMatrix<T> & matrix_in,
                 NumericVector<T> & solution_in,
                 NumericVector<T> & rhs_in,
                 const double tol,
                 const unsigned int m_its) override;
 
  virtual std::pair<unsigned int, Real>
  solve (SparseMatrix<T> & matrix,
         SparseMatrix<T> & preconditioner,
         NumericVector<T> & solution,
         NumericVector<T> & rhs,
         const double tol,
         const unsigned int m_its) override;
 
  virtual std::pair<unsigned int, Real>
  solve (const ShellMatrix<T> & shell_matrix,
         NumericVector<T> & solution_in,
         NumericVector<T> & rhs_in,
         const double tol,
         const unsigned int m_its) override;
 
  virtual std::pair<unsigned int, Real>
  solve (const ShellMatrix<T> & shell_matrix,
         const SparseMatrix<T> & precond_matrix,
         NumericVector<T> & solution_in,
         NumericVector<T> & rhs_in,
         const double tol,
         const unsigned int m_its) override;
 
  PC pc() { this->init(); return _pc; }
 
  KSP ksp() { this->init(); return _ksp; }
 
  void get_residual_history(std::vector<double> & hist);
 
  Real get_initial_residual();
 
  virtual LinearConvergenceReason get_converged_reason() const override;
 
private:
 
  void set_petsc_solver_type ();
 
  static PetscErrorCode _petsc_shell_matrix_mult(Mat mat, Vec arg, Vec dest);
 
  static PetscErrorCode _petsc_shell_matrix_mult_add(Mat mat, Vec arg, Vec add, Vec dest);
 
  static PetscErrorCode _petsc_shell_matrix_get_diagonal(Mat mat, Vec dest);
 
  PC _pc;
 
  KSP _ksp;
 
  IS _restrict_solve_to_is;
 
  IS _restrict_solve_to_is_complement;
 
  PetscInt _restrict_solve_to_is_local_size() const;
 
  void _create_complement_is (const NumericVector<T> & vec_in);
 
  SubsetSolveMode _subset_solve_mode;
};
 
 
/*----------------------- functions ----------------------------------*/
template <typename T>
inline
PetscLinearSolver<T>::~PetscLinearSolver ()
{
  this->clear ();
}
 
 
 
template <typename T>
inline PetscInt
PetscLinearSolver<T>::_restrict_solve_to_is_local_size() const
{
  libmesh_assert(_restrict_solve_to_is);
 
  PetscInt s;
  int ierr = ISGetLocalSize(_restrict_solve_to_is, &s);
  LIBMESH_CHKERR(ierr);
 
  return s;
}
 
 
 
template <typename T>
void
PetscLinearSolver<T>::_create_complement_is (const NumericVector<T> &
#if PETSC_VERSION_LESS_THAN(3,0,0)
                                             // unnamed to avoid compiler "unused parameter" warning
#else
                                             vec_in
#endif
                                             )
{
  libmesh_assert(_restrict_solve_to_is);
#if PETSC_VERSION_LESS_THAN(3,0,0)
  // No ISComplement in PETSc 2.3.3
  libmesh_not_implemented();
#else
  if (_restrict_solve_to_is_complement==nullptr)
    {
      int ierr = ISComplement(_restrict_solve_to_is,
                              vec_in.first_local_index(),
                              vec_in.last_local_index(),
                              &_restrict_solve_to_is_complement);
      LIBMESH_CHKERR(ierr);
    }
#endif
}
 
 
 
} // namespace libMesh
 
 
#endif // #ifdef LIBMESH_HAVE_PETSC
#endif // LIBMESH_PETSC_LINEAR_SOLVER_H