petsc_nonlinear_solver.h

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// The libMesh Finite Element Library.
// Copyright (C) 2002-2026 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_NONLINEAR_SOLVER_H
#define LIBMESH_PETSC_NONLINEAR_SOLVER_H
 
#include "libmesh/libmesh_config.h"
 
// Petsc include files.
#ifdef LIBMESH_HAVE_PETSC
 
// Local includes
#include "libmesh/nonlinear_solver.h"
#include "libmesh/petsc_macro.h"
#include "libmesh/wrapped_petsc.h"
#include "libmesh/petsc_dm_wrapper.h"
#include "libmesh/petsc_mffd_matrix.h"
 
// PETSc includes
#ifdef I
# define LIBMESH_SAW_I
#endif
#include <petscsnes.h>
#ifndef LIBMESH_SAW_I
# undef I // Avoid complex.h contamination
#endif
 
namespace libMesh
{
class ResidualContext;
 
// Allow users access to these functions in case they want to reuse them.  Users shouldn't
// need access to these most of the time as they are used internally by this object.
extern "C"
{
  PetscErrorCode libmesh_petsc_recalculate_monitor(SNES snes, PetscInt it, PetscReal norm, void* mctx);
  PetscErrorCode libmesh_petsc_snes_monitor (SNES, PetscInt its, PetscReal fnorm, void *);
  PetscErrorCode libmesh_petsc_snes_residual (SNES, Vec x, Vec r, void * ctx);
  PetscErrorCode libmesh_petsc_snes_fd_residual (SNES, Vec x, Vec r, void * ctx);
  PetscErrorCode libmesh_petsc_snes_mffd_residual (SNES snes, Vec x, Vec r, void * ctx);
  PetscErrorCode libmesh_petsc_snes_mffd_interface (void * ctx, Vec x, Vec r);
  PetscErrorCode libmesh_petsc_snes_jacobian (SNES, Vec x, Mat jac, Mat pc, void * ctx);
  PetscErrorCode libmesh_petsc_snes_precheck(SNESLineSearch, Vec X, Vec Y, PetscBool * changed, void * context);
  PetscErrorCode libmesh_petsc_snes_postcheck(SNESLineSearch, Vec x, Vec y, Vec w, PetscBool * changed_y, PetscBool * changed_w, void * context);
  PetscErrorCode libmesh_petsc_linesearch_shellfunc(SNESLineSearch linesearch, void * ctx);
}
 
template <typename T>
class PetscNonlinearSolver : public NonlinearSolver<T>
{
public:
  typedef NonlinearImplicitSystem sys_type;
 
  explicit
  PetscNonlinearSolver (sys_type & system);
 
  ~PetscNonlinearSolver ();
 
  virtual void clear () override;
 
  virtual void init (const char * name = nullptr) override;
 
  SNES snes(const char * name = nullptr);
 
  virtual std::pair<unsigned int, Real>
  solve (SparseMatrix<T> &,                     // System Jacobian Matrix
         NumericVector<T> &,                    // Solution vector
         NumericVector<T> &,                    // Residual vector
         const double,                         // Stopping tolerance
         const unsigned int) override; // N. Iterations
 
  virtual void print_converged_reason() override;
 
  SNESConvergedReason get_converged_reason();
 
  virtual int get_total_linear_iterations() override;
 
  virtual unsigned get_current_nonlinear_iteration_number() const override
  { return _current_nonlinear_iteration_number; }
 
  void set_residual_zero_out(bool state) { _zero_out_residual = state; }
 
  void set_jacobian_zero_out(bool state) { _zero_out_jacobian = state; }
 
  void use_default_monitor(bool state) { _default_monitor = state; }
 
  void set_snesmf_reuse_base(bool state) { _snesmf_reuse_base = state; }
 
  bool snes_mf_reuse_base() const { return _snesmf_reuse_base; }
 
  void set_computing_base_vector(bool computing_base_vector) { _computing_base_vector = computing_base_vector; }
 
  bool computing_base_vector() const { return _computing_base_vector; }
 
  class ComputeLineSearchObject
  {
  public:
    virtual ~ComputeLineSearchObject () = default;
 
    virtual void linesearch (SNESLineSearch linesearch) = 0;
  };
 
  std::unique_ptr<ComputeLineSearchObject> linesearch_object;
 
  void setup_default_monitor();
 
  virtual bool reuse_preconditioner() const override;
 
  virtual unsigned int reuse_preconditioner_max_linear_its() const override;
 
  virtual void force_new_preconditioner() override;
 
protected:
 
  WrappedPetsc<SNES> _snes;
 
  SNESConvergedReason _reason;
 
  PetscInt _n_linear_iterations;
 
  unsigned _current_nonlinear_iteration_number;
 
  bool _zero_out_residual;
 
  bool _zero_out_jacobian;
 
  bool _default_monitor;
 
  bool _snesmf_reuse_base;
 
  void build_mat_null_space(NonlinearImplicitSystem::ComputeVectorSubspace * computeSubspaceObject,
                            void (*)(std::vector<NumericVector<Number> *> &, sys_type &),
                            MatNullSpace *);
 
  bool _computing_base_vector;
 
  bool _setup_reuse;
 
#if defined(LIBMESH_ENABLE_AMR) && defined(LIBMESH_HAVE_METAPHYSICL)
  PetscDMWrapper _dm_wrapper;
#endif
 
  PetscMFFDMatrix<Number> _mffd_jac;
 
private:
  friend ResidualContext libmesh_petsc_snes_residual_helper (SNES snes, Vec x, void * ctx);
  friend PetscErrorCode libmesh_petsc_snes_residual (SNES snes, Vec x, Vec r, void * ctx);
  friend PetscErrorCode libmesh_petsc_snes_fd_residual (SNES snes, Vec x, Vec r, void * ctx);
  friend PetscErrorCode libmesh_petsc_snes_mffd_residual (SNES snes, Vec x, Vec r, void * ctx);
  friend PetscErrorCode libmesh_petsc_snes_jacobian (SNES snes, Vec x, Mat jac, Mat pc, void * ctx);
  friend PetscErrorCode libmesh_petsc_snes_precheck (SNESLineSearch,
                                                     Vec X,
                                                     Vec Y,
                                                     PetscBool * changed,
                                                     void * context);
};
 
} // namespace libMesh
 
 
#endif // #ifdef LIBMESH_HAVE_PETSC
#endif // LIBMESH_PETSC_NONLINEAR_SOLVER_H