newmark_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_NEWMARK_SYSTEM_H
#define LIBMESH_NEWMARK_SYSTEM_H
 
// Local Includes
#include "libmesh/linear_implicit_system.h"
 
// C++ includes
 
namespace libMesh
{
 
class NewmarkSystem : public LinearImplicitSystem
{
public:
 
  NewmarkSystem (EquationSystems & es,
                 const std::string & name,
                 const unsigned int number);
 
  NewmarkSystem (const NewmarkSystem &) = delete;
  NewmarkSystem & operator= (const NewmarkSystem &) = delete;
  NewmarkSystem (NewmarkSystem &&) = default;
  NewmarkSystem & operator= (NewmarkSystem &&) = delete;
  virtual ~NewmarkSystem ();
 
  typedef NewmarkSystem sys_type;
 
  virtual void clear () override;
 
  virtual void reinit () override;
 
  virtual void assemble () override;
 
  virtual std::string system_type () const override { return "Newmark"; }
 
 
  //---------------------------------------------------------
  // These members are specific to the Newmark system
  //
 
  void initial_conditions ();
 
  void compute_matrix ();
 
  void update_rhs ();
 
  void update_u_v_a ();
 
  void set_newmark_parameters (const Real delta_T = _default_timestep,
                               const Real alpha   = _default_alpha,
                               const Real delta   = _default_delta);
 
private:
 
  Real _a_0;
  Real _a_1;
  Real _a_2;
  Real _a_3;
  Real _a_4;
  Real _a_5;
  Real _a_6;
  Real _a_7;
 
  bool _finished_assemble;
 
  static const Real _default_alpha;
 
  static const Real _default_delta;
 
  static const Real _default_timestep;
};
 
} // namespace libMesh
 
#endif // LIBMESH_NEWMARK_SYSTEM_H