petsc_solver.cc

// ---------------------------------------------------------------------
//
// Copyright (C) 2004 - 2018 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library 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 deal.II distribution.
//
// ---------------------------------------------------------------------


#include <deal.II/base/logstream.h>
#include <deal.II/base/std_cxx14/memory.h>
#include <deal.II/lac/petsc_solver.h>

#ifdef DEAL_II_WITH_PETSC

#  include <deal.II/lac/exceptions.h>
#  include <deal.II/lac/petsc_compatibility.h>
#  include <deal.II/lac/petsc_matrix_base.h>
#  include <deal.II/lac/petsc_vector_base.h>
#  include <deal.II/lac/petsc_precondition.h>
#  include <cmath>

#include <petscversion.h>

DEAL_II_NAMESPACE_OPEN

namespace PETScWrappers
{

  SolverBase::SolverData::~SolverData ()
  {
    destroy_krylov_solver (ksp);
  }



  SolverBase::SolverBase (SolverControl  &cn,
                          const MPI_Comm &mpi_communicator)
    :
    solver_control (cn),
    mpi_communicator (mpi_communicator)
  {}



  void
  SolverBase::solve (const MatrixBase         &A,
                     VectorBase               &x,
                     const VectorBase         &b,
                     const PreconditionerBase &preconditioner)
  {
    /*
      TODO: PETSc duplicates communicators, so this does not work (you put MPI_COMM_SELF in, but get something other out when you ask PETSc for the communicator. This mainly fails due to the MatrixFree classes, that can not ask PETSc for a communicator. //Timo Heister
    Assert(A.get_mpi_communicator()==mpi_communicator, ExcMessage("PETSc Solver and Matrix need to use the same MPI_Comm."));
    Assert(x.get_mpi_communicator()==mpi_communicator, ExcMessage("PETSc Solver and Vector need to use the same MPI_Comm."));
    Assert(b.get_mpi_communicator()==mpi_communicator, ExcMessage("PETSc Solver and Vector need to use the same MPI_Comm."));
    */

    // first create a solver object if this
    // is necessary
    if (solver_data.get() == nullptr)
      {
        solver_data = std_cxx14::make_unique<SolverData>();

        PetscErrorCode ierr = KSPCreate (mpi_communicator, &solver_data->ksp);
        AssertThrow (ierr == 0, ExcPETScError(ierr));

        // let derived classes set the solver
        // type, and the preconditioning
        // object set the type of
        // preconditioner
        set_solver_type (solver_data->ksp);

        ierr = KSPSetPC (solver_data->ksp, preconditioner.get_pc());
        AssertThrow (ierr == 0, ExcPETScError(ierr));

        // make sure the preconditioner has an associated matrix set
        const Mat B = preconditioner;
        AssertThrow (B != nullptr,
                     ExcMessage("PETSc preconditioner should have an"
                                "associated matrix set to be used in solver."));

        // setting the preconditioner overwrites the used matrices.
        // hence, we need to set the matrices after the preconditioner.
#if DEAL_II_PETSC_VERSION_LT(3, 5, 0)
        // the last argument is irrelevant here,
        // since we use the solver only once anyway
        ierr = KSPSetOperators (solver_data->ksp, A, preconditioner,
                                SAME_PRECONDITIONER);
#else
        ierr = KSPSetOperators (solver_data->ksp, A, preconditioner);
#endif
        AssertThrow (ierr == 0, ExcPETScError(ierr));

        // then a convergence monitor
        // function. that function simply
        // checks with the solver_control
        // object we have in this object for
        // convergence
        ierr = KSPSetConvergenceTest (solver_data->ksp, &convergence_test,
                                      reinterpret_cast<void *>(&solver_control),
                                      nullptr);
        AssertThrow (ierr == 0, ExcPETScError(ierr));
      }

    // set the command line option prefix name
    PetscErrorCode ierr = KSPSetOptionsPrefix(solver_data->ksp, prefix_name.c_str());
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // set the command line options provided
    // by the user to override the defaults
    ierr = KSPSetFromOptions (solver_data->ksp);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // then do the real work: set up solver
    // internal data and solve the
    // system.
    ierr = KSPSetUp (solver_data->ksp);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    ierr = KSPSolve (solver_data->ksp, b, x);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // do not destroy solver object
//    solver_data.reset ();

    // in case of failure: throw
    // exception
    if (solver_control.last_check() != SolverControl::success)
      AssertThrow(false, SolverControl::NoConvergence (solver_control.last_step(),
                                                       solver_control.last_value()));
    // otherwise exit as normal
  }


  void
  SolverBase::set_prefix(const std::string &prefix)
  {
    prefix_name = prefix ;
  }


  void
  SolverBase::reset()
  {
    solver_data.reset ();
  }


  SolverControl &
  SolverBase::control() const
  {
    return solver_control;
  }


  int
  SolverBase::convergence_test (KSP                 /*ksp*/,
                                const PetscInt      iteration,
                                const PetscReal     residual_norm,
                                KSPConvergedReason *reason,
                                void               *solver_control_x)
  {
    SolverControl &solver_control = *reinterpret_cast<SolverControl *>(solver_control_x);

    const SolverControl::State state
      = solver_control.check (iteration, residual_norm);

    switch (state)
      {
      case ::SolverControl::iterate:
        *reason = KSP_CONVERGED_ITERATING;
        break;

      case ::SolverControl::success:
        *reason = static_cast<KSPConvergedReason>(1);
        break;

      case ::SolverControl::failure:
        if (solver_control.last_step() > solver_control.max_steps())
          *reason = KSP_DIVERGED_ITS;
        else
          *reason = KSP_DIVERGED_DTOL;
        break;

      default:
        Assert (false, ExcNotImplemented());
      }

    // return without failure
    return 0;
  }

  void
  SolverBase::initialize(const PreconditionerBase &preconditioner)
  {
    PetscErrorCode ierr;

    solver_data = std_cxx14::make_unique<SolverData>();

    ierr = KSPCreate (mpi_communicator, &solver_data->ksp);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // let derived classes set the solver
    // type, and the preconditioning
    // object set the type of
    // preconditioner
    set_solver_type (solver_data->ksp);

    ierr = KSPSetPC (solver_data->ksp, preconditioner.get_pc());
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // then a convergence monitor
    // function. that function simply
    // checks with the solver_control
    // object we have in this object for
    // convergence
    ierr = KSPSetConvergenceTest (solver_data->ksp, &convergence_test,
                                  reinterpret_cast<void *>(&solver_control),
                                  nullptr);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // set the command line options provided
    // by the user to override the defaults
    ierr = KSPSetFromOptions (solver_data->ksp);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }



  /* ---------------------- SolverRichardson ------------------------ */

  SolverRichardson::AdditionalData::
  AdditionalData (const double omega)
    :
    omega (omega)
  {}



  SolverRichardson::SolverRichardson (SolverControl        &cn,
                                      const MPI_Comm       &mpi_communicator,
                                      const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverRichardson::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPRICHARDSON);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // set the damping factor from the data
    ierr = KSPRichardsonSetScale (ksp, additional_data.omega);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // in the deal.II solvers, we always
    // honor the initial guess in the
    // solution vector. do so here as well:
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // Hand over the absolute
    // tolerance and the maximum
    // iteration number to the PETSc
    // convergence criterion. The
    // custom deal.II SolverControl
    // object is ignored by the PETSc
    // Richardson method (when no
    // PETSc monitoring is present),
    // since in this case PETSc
    // uses a faster version of
    // the Richardson iteration,
    // where no residual is
    // available.
    ierr = KSPSetTolerances(ksp, PETSC_DEFAULT, this->solver_control.tolerance(),
                            PETSC_DEFAULT, this->solver_control.max_steps()+1);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SolverChebychev ------------------------ */

  SolverChebychev::SolverChebychev (SolverControl        &cn,
                                    const MPI_Comm       &mpi_communicator,
                                    const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverChebychev::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPCHEBYSHEV);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // in the deal.II solvers, we always
    // honor the initial guess in the
    // solution vector. do so here as well:
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SolverCG ------------------------ */

  SolverCG::SolverCG (SolverControl        &cn,
                      const MPI_Comm       &mpi_communicator,
                      const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverCG::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPCG);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // in the deal.II solvers, we always
    // honor the initial guess in the
    // solution vector. do so here as well:
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SolverBiCG ------------------------ */

  SolverBiCG::SolverBiCG (SolverControl        &cn,
                          const MPI_Comm       &mpi_communicator,
                          const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverBiCG::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPBICG);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // in the deal.II solvers, we always
    // honor the initial guess in the
    // solution vector. do so here as well:
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SolverGMRES ------------------------ */

  SolverGMRES::AdditionalData::
  AdditionalData (const unsigned int restart_parameter,
                  const bool right_preconditioning)
    :
    restart_parameter (restart_parameter),
    right_preconditioning (right_preconditioning)
  {}



  SolverGMRES::SolverGMRES (SolverControl        &cn,
                            const MPI_Comm       &mpi_communicator,
                            const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverGMRES::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPGMRES);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // set the restart parameter from the
    // data. we would like to use the simple
    // code that is commented out, but this
    // leads to nasty warning and error
    // messages due to some stupidity on
    // PETSc's side: KSPGMRESSetRestart is
    // implemented as a macro in which return
    // statements are hidden. This may work
    // if people strictly follow the PETSc
    // coding style of always having
    // functions return an integer error
    // code, but the present function isn't
    // like this.
    /*
        ierr = KSPGMRESSetRestart (ksp, additional_data.restart_parameter);
        AssertThrow (ierr == 0, ExcPETScError(ierr));
    */
    // so rather expand their macros by hand,
    // and do some equally nasty stuff that at
    // least doesn't yield warnings...
    int (*fun_ptr)(KSP,int);
    ierr = PetscObjectQueryFunction((PetscObject)(ksp),
                                    "KSPGMRESSetRestart_C",
                                    (void (* *)())&fun_ptr);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    ierr = (*fun_ptr)(ksp,additional_data.restart_parameter);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // Set preconditioning side to
    // right
    if (additional_data.right_preconditioning)
      {
        ierr = KSPSetPCSide(ksp, PC_RIGHT);
        AssertThrow (ierr == 0, ExcPETScError(ierr));
      }

    // in the deal.II solvers, we always
    // honor the initial guess in the
    // solution vector. do so here as well:
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SolverBicgstab ------------------------ */

  SolverBicgstab::SolverBicgstab (SolverControl        &cn,
                                  const MPI_Comm       &mpi_communicator,
                                  const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverBicgstab::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPBCGS);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // in the deal.II solvers, we always
    // honor the initial guess in the
    // solution vector. do so here as well:
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SolverCGS ------------------------ */

  SolverCGS::SolverCGS (SolverControl        &cn,
                        const MPI_Comm       &mpi_communicator,
                        const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverCGS::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPCGS);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // in the deal.II solvers, we always
    // honor the initial guess in the
    // solution vector. do so here as well:
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SolverTFQMR ------------------------ */

  SolverTFQMR::SolverTFQMR (SolverControl        &cn,
                            const MPI_Comm       &mpi_communicator,
                            const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverTFQMR::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPTFQMR);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // in the deal.II solvers, we always
    // honor the initial guess in the
    // solution vector. do so here as well:
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SolverTCQMR ------------------------ */

  SolverTCQMR::SolverTCQMR (SolverControl        &cn,
                            const MPI_Comm       &mpi_communicator,
                            const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverTCQMR::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPTCQMR);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // in the deal.II solvers, we always
    // honor the initial guess in the
    // solution vector. do so here as well:
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SolverCR ------------------------ */

  SolverCR::SolverCR (SolverControl        &cn,
                      const MPI_Comm       &mpi_communicator,
                      const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverCR::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPCR);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // in the deal.II solvers, we always
    // honor the initial guess in the
    // solution vector. do so here as well:
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SolverLSQR ------------------------ */

  SolverLSQR::SolverLSQR (SolverControl        &cn,
                          const MPI_Comm       &mpi_communicator,
                          const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverLSQR::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPLSQR);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // in the deal.II solvers, we always
    // honor the initial guess in the
    // solution vector. do so here as well:
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SolverPreOnly ------------------------ */

  SolverPreOnly::SolverPreOnly (SolverControl        &cn,
                                const MPI_Comm       &mpi_communicator,
                                const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data)
  {}


  void
  SolverPreOnly::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPPREONLY);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    // The KSPPREONLY solver of
    // PETSc never calls the convergence
    // monitor, which leads to failure
    // even when everything was ok.
    // Therefore the SolverControl status
    // is set to some nice values, which
    // guarantee a nice result at the end
    // of the solution process.
    solver_control.check (1, 0.0);

    // Using the PREONLY solver with
    // a nonzero initial guess leads
    // PETSc to produce some error messages.
    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_FALSE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }


  /* ---------------------- SparseDirectMUMPS------------------------ */

  SparseDirectMUMPS::SolverDataMUMPS::~SolverDataMUMPS ()
  {
    destroy_krylov_solver (ksp);
    // the 'pc' object is owned by the 'ksp' object, and consequently
    // does not have to be destroyed explicitly here
  }


  SparseDirectMUMPS::SparseDirectMUMPS (SolverControl     &cn,
                                        const MPI_Comm       &mpi_communicator,
                                        const AdditionalData &data)
    :
    SolverBase (cn, mpi_communicator),
    additional_data (data),
    symmetric_mode(false)
  {}


  void
  SparseDirectMUMPS::set_solver_type (KSP &ksp) const
  {
    PetscErrorCode ierr = KSPSetType (ksp, KSPPREONLY);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    solver_control.check (1, 0.0);

    ierr = KSPSetInitialGuessNonzero (ksp, PETSC_FALSE);
    AssertThrow (ierr == 0, ExcPETScError(ierr));
  }

  void
  SparseDirectMUMPS::solve (const MatrixBase &A,
                            VectorBase       &x,
                            const VectorBase &b)
  {
#ifdef DEAL_II_PETSC_WITH_MUMPS

    Mat F;

    PetscInt ival=2, icntl=7;
    PetscInt its;
    PetscReal rnorm;

    if (solver_data == nullptr)
      {
        solver_data = std_cxx14::make_unique<SolverDataMUMPS >();

        PetscErrorCode ierr = KSPCreate (mpi_communicator, &solver_data->ksp);
        AssertThrow (ierr == 0, ExcPETScError(ierr));

#if DEAL_II_PETSC_VERSION_LT(3, 5, 0)
        ierr = KSPSetOperators (solver_data->ksp, A, A,
                                DIFFERENT_NONZERO_PATTERN);
#else
        ierr = KSPSetOperators (solver_data->ksp, A, A);
#endif
        AssertThrow (ierr == 0, ExcPETScError(ierr));

        set_solver_type (solver_data->ksp);

        ierr = KSPGetPC (solver_data->ksp, & solver_data->pc);
        AssertThrow (ierr == 0, ExcPETScError(ierr));

        if (symmetric_mode)
          ierr = PCSetType (solver_data->pc, PCCHOLESKY);
        else
          ierr = PCSetType (solver_data->pc, PCLU);
        AssertThrow (ierr == 0, ExcPETScError(ierr));

        ierr = KSPSetConvergenceTest (solver_data->ksp, &convergence_test,
                                      reinterpret_cast<void *>(&solver_control),
                                      PETSC_NULL);
        AssertThrow (ierr == 0, ExcPETScError(ierr));

#if DEAL_II_PETSC_VERSION_LT(3, 9, 0)
        ierr = PCFactorSetMatSolverPackage (solver_data->pc, MATSOLVERMUMPS);
#else
        ierr = PCFactorSetMatSolverType (solver_data->pc, MATSOLVERMUMPS);
#endif
        AssertThrow (ierr == 0, ExcPETScError (ierr));

#if DEAL_II_PETSC_VERSION_LT(3, 9, 0)
        ierr = PCFactorSetUpMatSolverPackage (solver_data->pc);
#else
        ierr = PCFactorSetUpMatSolverType (solver_data->pc);
#endif
        AssertThrow (ierr == 0, ExcPETScError(ierr));

        ierr = PCFactorGetMatrix(solver_data->pc, &F);
        AssertThrow (ierr == 0, ExcPETScError(ierr));

        ierr = MatMumpsSetIcntl (F, icntl, ival);
        AssertThrow (ierr == 0, ExcPETScError(ierr));

        ierr = KSPSetOptionsPrefix(solver_data->ksp, prefix_name.c_str());
        AssertThrow (ierr == 0, ExcPETScError(ierr));

        ierr = KSPSetFromOptions (solver_data->ksp);
        AssertThrow (ierr == 0, ExcPETScError(ierr));

      }

    PetscErrorCode ierr = KSPSolve (solver_data->ksp, b, x);
    AssertThrow (ierr == 0, ExcPETScError(ierr));

    if (solver_control.last_check() != SolverControl::success)
      {
        AssertThrow(false, SolverControl::NoConvergence (solver_control.last_step(),
                                                         solver_control.last_value()));
      }
    else
      {
        ierr = KSPGetIterationNumber (solver_data->ksp, &its);
        AssertThrow (ierr == 0, ExcPETScError(ierr));
        ierr = KSPGetResidualNorm (solver_data->ksp, &rnorm);
        AssertThrow (ierr == 0, ExcPETScError(ierr));
      }

#else  // DEAL_II_PETSC_WITH_MUMPS
    Assert (false,
            ExcMessage ("Your PETSc installation does not include a copy of "
                        "the MUMPS package necessary for this solver. You will need to configure "
                        "PETSc so that it includes MUMPS, recompile it, and then re-configure "
                        "and recompile deal.II as well."));

    // Cast to void to silence compiler warnings
    (void) A;
    (void) x;
    (void) b;
#endif

  }

  PetscErrorCode SparseDirectMUMPS::convergence_test (KSP               /*ksp*/,
                                                      const PetscInt      iteration,
                                                      const PetscReal     residual_norm,
                                                      KSPConvergedReason *reason,
                                                      void               *solver_control_x)
  {
    SolverControl &solver_control = *reinterpret_cast<SolverControl *>(solver_control_x);

    const SolverControl::State state
      = solver_control.check (iteration, residual_norm);

    switch (state)
      {
      case ::SolverControl::iterate:
        *reason = KSP_CONVERGED_ITERATING;
        break;

      case ::SolverControl::success:
        *reason = static_cast<KSPConvergedReason>(1);
        break;

      case ::SolverControl::failure:
        if (solver_control.last_step() > solver_control.max_steps())
          *reason = KSP_DIVERGED_ITS;
        else
          *reason = KSP_DIVERGED_DTOL;
        break;

      default:
        Assert (false, ExcNotImplemented());
      }

    return 0;
  }

  void
  SparseDirectMUMPS::set_symmetric_mode(const bool flag)
  {
    symmetric_mode = flag;
  }

}

DEAL_II_NAMESPACE_CLOSE

#endif // DEAL_II_WITH_PETSC