newmark_system.h

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// The libMesh Finite Element Library.
// Copyright (C) 2002-2018 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 ();

  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