ode.hpp

Go to the documentation of this file.

// Copyright (c) 2010, Lawrence Livermore National Security, LLC. Produced at
// the Lawrence Livermore National Laboratory. LLNL-CODE-443211. All Rights
// reserved. See file COPYRIGHT for details.
//
// This file is part of the MFEM library. For more information and source code
// availability see http://mfem.org.
//
// MFEM 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) version 2.1 dated February 1999.

#ifndef MFEM_ODE
#define MFEM_ODE

#include "../config/config.hpp"
#include "operator.hpp"

namespace mfem
{

class ODESolver
{
protected:
   TimeDependentOperator *f; // f(.,t) : R^n --> R^n

public:
   ODESolver() : f(NULL) { }

   virtual void Init(TimeDependentOperator &_f) { f = &_f; }

   virtual void Step(Vector &x, double &t, double &dt) = 0;

   virtual ~ODESolver() { }
};


class ForwardEulerSolver : public ODESolver
{
private:
   Vector dxdt;

public:
   virtual void Init(TimeDependentOperator &_f);

   virtual void Step(Vector &x, double &t, double &dt);
};


class RK2Solver : public ODESolver
{
private:
   double a;
   Vector dxdt, x1;

public:
   RK2Solver(const double _a = 2./3.) : a(_a) { }

   virtual void Init(TimeDependentOperator &_f);

   virtual void Step(Vector &x, double &t, double &dt);
};


class RK3SSPSolver : public ODESolver
{
private:
   Vector y, k;

public:
   virtual void Init(TimeDependentOperator &_f);

   virtual void Step(Vector &x, double &t, double &dt);
};


class RK4Solver : public ODESolver
{
private:
   Vector y, k, z;

public:
   virtual void Init(TimeDependentOperator &_f);

   virtual void Step(Vector &x, double &t, double &dt);
};


class ExplicitRKSolver : public ODESolver
{
private:
   int s;
   const double *a, *b, *c;
   Vector y, *k;

public:
   ExplicitRKSolver(int _s, const double *_a, const double *_b,
                    const double *_c);

   virtual void Init(TimeDependentOperator &_f);

   virtual void Step(Vector &x, double &t, double &dt);

   virtual ~ExplicitRKSolver();
};


class RK6Solver : public ExplicitRKSolver
{
private:
   static const double a[28], b[8], c[7];

public:
   RK6Solver() : ExplicitRKSolver(8, a, b, c) { }
};


class RK8Solver : public ExplicitRKSolver
{
private:
   static const double a[66], b[12], c[11];

public:
   RK8Solver() : ExplicitRKSolver(12, a, b, c) { }
};


class BackwardEulerSolver : public ODESolver
{
protected:
   Vector k;

public:
   virtual void Init(TimeDependentOperator &_f);

   virtual void Step(Vector &x, double &t, double &dt);
};


class ImplicitMidpointSolver : public ODESolver
{
protected:
   Vector k;

public:
   virtual void Init(TimeDependentOperator &_f);

   virtual void Step(Vector &x, double &t, double &dt);
};


class SDIRK23Solver : public ODESolver
{
protected:
   double gamma;
   Vector k, y;

public:
   SDIRK23Solver(int gamma_opt = 1);

   virtual void Init(TimeDependentOperator &_f);

   virtual void Step(Vector &x, double &t, double &dt);
};


class SDIRK34Solver : public ODESolver
{
protected:
   Vector k, y, z;

public:
   virtual void Init(TimeDependentOperator &_f);

   virtual void Step(Vector &x, double &t, double &dt);
};


class SDIRK33Solver : public ODESolver
{
protected:
   Vector k, y;

public:
   virtual void Init(TimeDependentOperator &_f);

   virtual void Step(Vector &x, double &t, double &dt);
};

}

#endif