/usr/include/sofa/component/odesolver/RungeKutta4Solver.h is in libsofa1-dev 1.0~beta4-10ubuntu2.
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* SOFA, Simulation Open-Framework Architecture, version 1.0 beta 4 *
* (c) 2006-2009 MGH, INRIA, USTL, UJF, CNRS *
* *
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *
*******************************************************************************
* SOFA :: Modules *
* *
* Authors: The SOFA Team and external contributors (see Authors.txt) *
* *
* Contact information: contact@sofa-framework.org *
******************************************************************************/
#ifndef SOFA_COMPONENT_ODESOLVER_RUNGEKUTTA4SOLVER_H
#define SOFA_COMPONENT_ODESOLVER_RUNGEKUTTA4SOLVER_H
#include <sofa/core/componentmodel/behavior/OdeSolver.h>
#include <sofa/component/odesolver/OdeSolverImpl.h>
namespace sofa
{
namespace component
{
namespace odesolver
{
/** A popular time integration method, much more precise than the EulerSolver */
class SOFA_COMPONENT_ODESOLVER_API RungeKutta4Solver : public sofa::component::odesolver::OdeSolverImpl
{
public:
void solve (double dt);
/// Given an input derivative order (0 for position, 1 for velocity, 2 for acceleration),
/// how much will it affect the output derivative of the given order.
/// @TODO use real factors depending on the current RK4 step
virtual double getIntegrationFactor(int inputDerivative, int outputDerivative) const
{
const double dt = getContext()->getDt();
double matrix[3][3] = {
{ 1, dt/2, 0},
{ 0, 1, dt/2},
{ 0, 0, 0}};
if (inputDerivative >= 3 || outputDerivative >= 3)
return 0;
else
return matrix[outputDerivative][inputDerivative];
}
/// Given a solution of the linear system,
/// how much will it affect the output derivative of the given order.
/// @TODO use real factors depending on the current RK4 step
virtual double getSolutionIntegrationFactor(int outputDerivative) const
{
const double dt = getContext()->getDt();
double vect[3] = { 0.0, dt/2, 1};
if (outputDerivative >= 3)
return 0;
else
return vect[outputDerivative];
}
};
} // namespace odesolver
} // namespace component
} // namespace sofa
#endif
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