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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_INTERACTIONFORCEFIELD_REPULSIVESPRINGFORCEFIELD_INL
#define SOFA_COMPONENT_INTERACTIONFORCEFIELD_REPULSIVESPRINGFORCEFIELD_INL
#include <sofa/component/interactionforcefield/RepulsiveSpringForceField.h>
#include <sofa/component/forcefield/StiffSpringForceField.inl>
namespace sofa
{
namespace component
{
namespace interactionforcefield
{
template<class DataTypes>
void RepulsiveSpringForceField<DataTypes>::addForce(VecDeriv& f1, VecDeriv& f2, const VecCoord& x1, const VecCoord& x2, const VecDeriv& v1, const VecDeriv& v2)
{
const helper::vector<Spring>& springs= this->springs.getValue();
this->dfdx.resize(springs.size());
f1.resize(x1.size());
f2.resize(x2.size());
for (unsigned int i=0; i<springs.size(); i++)
{
#if 1
int a = springs[i].m1;
int b = springs[i].m2;
Coord u = x2[b]-x1[a];
Real d = u.norm();
if (d < springs[i].initpos)
{
Real inverseLength = 1.0f/d;
u *= inverseLength;
Real elongation = (Real)(d - springs[i].initpos);
Deriv relativeVelocity = v2[b]-v1[a];
Real elongationVelocity = dot(u,relativeVelocity);
Real forceIntensity = (Real)(springs[i].ks*elongation+springs[i].kd*elongationVelocity);
Deriv force = u*forceIntensity;
f1[a]+=force;
f2[b]-=force;
Mat& m = this->dfdx[i];
Real tgt = forceIntensity * inverseLength;
for( int j=0; j<N; ++j )
{
for( int k=0; k<N; ++k )
{
m[j][k] = ((Real)springs[i].ks-tgt) * u[j] * u[k];
}
m[j][j] += tgt;
}
}
else
#endif
{
Mat& m = this->dfdx[i];
for( int j=0; j<N; ++j )
for( int k=0; k<N; ++k )
m[j][k] = 0.0;
}
}
}
template <class DataTypes>
double RepulsiveSpringForceField<DataTypes>::getPotentialEnergy()
{
serr<<"RepulsiveSpringForceField::getPotentialEnergy-not-implemented !!!"<<sendl;
return 0;
}
} // namespace interactionforcefield
} // namespace component
} // namespace sofa
#endif
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