fem_system.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_FEM_SYSTEM_H
#define LIBMESH_FEM_SYSTEM_H
 
// Local Includes
#include "libmesh/diff_system.h"
#include "libmesh/fem_physics.h"
 
// C++ includes
#include <cstddef>
 
namespace libMesh
{
 
// Forward Declarations
class DiffContext;
class FEMContext;
 
 
class FEMSystem : public DifferentiableSystem,
                  public FEMPhysics
{
public:
 
  FEMSystem (EquationSystems & es,
             const std::string & name,
             const unsigned int number);
 
  FEMSystem (const FEMSystem &) = delete;
  FEMSystem & operator= (const FEMSystem &) = delete;
  FEMSystem (FEMSystem &&) = delete;
  FEMSystem & operator= (FEMSystem &&) = delete;
  virtual ~FEMSystem ();
 
  typedef FEMSystem sys_type;
 
  typedef DifferentiableSystem Parent;
 
  virtual void assembly (bool get_residual,
                         bool get_jacobian,
                         bool apply_heterogeneous_constraints = false,
                         bool apply_no_constraints = false) override;
 
  virtual void solve () override;
 
  void mesh_position_get();
 
  void mesh_position_set();
 
  virtual std::unique_ptr<DiffContext> build_context() override;
 
  /*
   * Prepares the result of a build_context() call for use.
   *
   * Most FEMSystem-based problems will need to reimplement this in order to
   * call FE::get_*() as their particular physics requires.
   */
  virtual void init_context(DiffContext &) override;
 
  virtual void postprocess () override;
 
  virtual void assemble_qoi (const QoISet & indices = QoISet()) override;
 
  virtual void assemble_qoi_derivative (const QoISet & qoi_indices = QoISet(),
                                        bool include_liftfunc = true,
                                        bool apply_constraints = true) override;
 
  bool fe_reinit_during_postprocess;
 
  Real numerical_jacobian_h;
 
  Real numerical_jacobian_h_for_var(unsigned int var_num) const;
 
  void set_numerical_jacobian_h_for_var(unsigned int var_num, Real new_h);
 
  Real verify_analytic_jacobians;
 
  typedef bool (TimeSolver::*TimeSolverResPtr)(bool, DiffContext &);
 
  void numerical_jacobian (TimeSolverResPtr res,
                           FEMContext & context) const;
 
  void numerical_elem_jacobian (FEMContext & context) const;
 
  void numerical_side_jacobian (FEMContext & context) const;
 
  void numerical_nonlocal_jacobian (FEMContext & context) const;
 
protected:
  virtual void init_data () override;
 
private:
  std::vector<Real> _numerical_jacobian_h_for_var;
};
 
// --------------------------------------------------------------
// FEMSystem inline methods
inline
Real
FEMSystem::numerical_jacobian_h_for_var(unsigned int var_num) const
{
  if ((var_num >= _numerical_jacobian_h_for_var.size()) ||
      _numerical_jacobian_h_for_var[var_num] == Real(0))
    return numerical_jacobian_h;
 
  return _numerical_jacobian_h_for_var[var_num];
}
 
inline
void FEMSystem::set_numerical_jacobian_h_for_var(unsigned int var_num,
                                                 Real new_h)
{
  if (_numerical_jacobian_h_for_var.size() <= var_num)
    _numerical_jacobian_h_for_var.resize(var_num+1,Real(0));
 
  libmesh_assert_greater(new_h, Real(0));
 
  _numerical_jacobian_h_for_var[var_num] = new_h;
}
 
} // namespace libMesh
 
 
#endif // LIBMESH_FEM_SYSTEM_H