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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 *
******************************************************************************/
// Author: François Faure, INRIA-UJF, (C) 2006
//
// Copyright: See COPYING file that comes with this distribution
#include <sofa/component/odesolver/EulerImplicitSolver.h>
#include <sofa/simulation/common/MechanicalVisitor.h>
#include <sofa/core/ObjectFactory.h>
#include <math.h>
#include <iostream>
#include "sofa/helper/system/thread/CTime.h"
namespace sofa
{
namespace component
{
namespace odesolver
{
using namespace sofa::defaulttype;
using namespace core::componentmodel::behavior;
EulerImplicitSolver::EulerImplicitSolver()
: f_rayleighStiffness( initData(&f_rayleighStiffness,0.1,"rayleighStiffness","Rayleigh damping coefficient related to stiffness") )
, f_rayleighMass( initData(&f_rayleighMass,0.1,"rayleighMass","Rayleigh damping coefficient related to mass"))
, f_velocityDamping( initData(&f_velocityDamping,0.,"vdamping","Velocity decay coefficient (no decay if null)") )
, f_verbose( initData(&f_verbose,false,"verbose","Dump system state at each iteration") )
{
}
void EulerImplicitSolver::init()
{
if (!this->getTags().empty())
{
sout << "EulerImplicitSolver: responsible for the following objects with tags " << this->getTags() << " :" << sendl;
helper::vector<core::objectmodel::BaseObject*> objs;
this->getContext()->get<core::objectmodel::BaseObject>(&objs,this->getTags(),sofa::core::objectmodel::BaseContext::SearchDown);
for (unsigned int i=0;i<objs.size();++i)
sout << " " << objs[i]->getClassName() << ' ' << objs[i]->getName() << sendl;
}
}
void EulerImplicitSolver::solve(double dt, sofa::core::componentmodel::behavior::BaseMechanicalState::VecId xResult, sofa::core::componentmodel::behavior::BaseMechanicalState::VecId vResult)
{
MultiVector pos(this, VecId::position());
MultiVector vel(this, VecId::velocity());
MultiVector f(this, VecId::force());
MultiVector b(this, VecId::V_DERIV);
//MultiVector p(this, VecId::V_DERIV);
//MultiVector q(this, VecId::V_DERIV);
//MultiVector q2(this, VecId::V_DERIV);
//MultiVector r(this, VecId::V_DERIV);
MultiVector x(this, VecId::V_DERIV);
double h = dt;
//const bool printLog = f_printLog.getValue();
const bool verbose = f_verbose.getValue();
//projectResponse(vel); // initial velocities are projected to the constrained space
// compute the right-hand term of the equation system
// accumulation through mappings is disabled as it will be done by addMBKv after all factors are computed
computeForce(b, true, false); // b = f0
// new more powerful visitors
// b += (h+rs)df/dx v - rd M v
// values are not cleared so that contributions from computeForces are kept and accumulated through mappings once at the end
addMBKv(b, (f_rayleighMass.getValue() == 0.0 ? 0.0 : -f_rayleighMass.getValue()), 0, h+f_rayleighStiffness.getValue(), false, true);
b.teq(h); // b = h(f0 + (h+rs)df/dx v - rd M v)
if( verbose )
serr<<"EulerImplicitSolver, f0 = "<< b <<sendl;
projectResponse(b); // b is projected to the constrained space
if( verbose )
serr<<"EulerImplicitSolver, projected f0 = "<< b <<sendl;
MultiMatrix matrix(this);
matrix = MechanicalMatrix::K * (-h*(h+f_rayleighStiffness.getValue())) + MechanicalMatrix::M * (1+h*f_rayleighMass.getValue());
//if( verbose )
// serr<<"EulerImplicitSolver, matrix = "<< (MechanicalMatrix::K * (-h*(h+f_rayleighStiffness.getValue())) + MechanicalMatrix::M * (1+h*f_rayleighMass.getValue())) << " = " << matrix <<sendl;
matrix.solve(x, b);
// projectResponse(x);
// x is the solution of the system
// apply the solution
MultiVector newPos(this, xResult);
MultiVector newVel(this, vResult);
#ifdef SOFA_NO_VMULTIOP // unoptimized version
//vel.peq( x ); // vel = vel + x
newVel.eq(vel, x);
//pos.peq( vel, h ); // pos = pos + h vel
newPos.eq(pos, newVel, h);
#else // single-operation optimization
{
typedef core::componentmodel::behavior::BaseMechanicalState::VMultiOp VMultiOp;
VMultiOp ops;
ops.resize(2);
ops[0].first = (VecId)newVel;
ops[0].second.push_back(std::make_pair((VecId)vel,1.0));
ops[0].second.push_back(std::make_pair((VecId)x,1.0));
ops[1].first = (VecId)newPos;
ops[1].second.push_back(std::make_pair((VecId)pos,1.0));
ops[1].second.push_back(std::make_pair((VecId)newVel,h));
simulation::MechanicalVMultiOpVisitor vmop(ops);
vmop.setTags(this->getTags());
vmop.execute(this->getContext());
}
#endif
addSeparateGravity(dt, newVel); // v += dt*g . Used if mass wants to added G separately from the other forces to v.
if (f_velocityDamping.getValue()!=0.0)
newVel *= exp(-h*f_velocityDamping.getValue());
if( verbose )
{
serr<<"EulerImplicitSolver, final x = "<< newPos <<sendl;
serr<<"EulerImplicitSolver, final v = "<< newVel <<sendl;
}
#ifdef SOFA_HAVE_LAPACK
applyConstraints();
#endif
}
SOFA_DECL_CLASS(EulerImplicitSolver)
int EulerImplicitSolverClass = core::RegisterObject("Implicit time integrator using backward Euler scheme")
.add< EulerImplicitSolver >()
.addAlias("EulerImplicit")
.addAlias("ImplicitEulerSolver")
.addAlias("ImplicitEuler")
;
} // namespace odesolver
} // namespace component
} // namespace sofa
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