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libmultiscale/src/stimulation/stimulation_rigidify.cc
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/**
* @file stimulation_rigidify.cc
*
* @author Guillaume Anciaux <guillaume.anciaux@epfl.ch>
*
* @date Wed Jul 09 21:59:47 2014
*
* @brief This stimulator allows to reduce the force to let a group act like a
* rigid body
*
* @section LICENSE
*
* Copyright (©) 2010-2011 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
* LibMultiScale 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 3 of the License, or (at your option) any
* later version.
*
* LibMultiScale 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 LibMultiScale. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include "stimulation_rigidify.hh"
#include "lib_continuum.hh"
#include "lib_dd.hh"
#include "lib_md.hh"
#include "lm_common.hh"
#include "lm_communicator.hh"
#include "ref_point_data.hh"
/* -------------------------------------------------------------------------- */
__BEGIN_LIBMULTISCALE__
/* -------------------------------------------------------------------------- */
StimulationRigidify::StimulationRigidify(const std::string &name)
: LMObject(name) {
for (UInt i = 0; i < 3; ++i) {
total_force[i] = 0.;
}
factor = 1.;
}
/* -------------------------------------------------------------------------- */
StimulationRigidify::~StimulationRigidify() {}
/* -------------------------------------------------------------------------- */
template <typename Cont> void StimulationRigidify::stimulate(Cont &cont) {
constexpr UInt Dim = Cont::Dim;
UInt cpt = cont.size();
Vector<Dim> f = Vector<Dim>::Zero();
for (auto &&at : cont) {
f += at.force();
}
// then reduce for multiple processors
CommGroup &group = cont.getCommGroup();
group.allReduce(f.data(), Dim, "reduce force", OP_SUM);
group.allReduce(&cpt, 1, "reduce number atoms", OP_SUM);
f += total_force.cast<Real>().block<Dim, 1u>(0, 0);
f /= cpt;
for (auto &&at : cont) {
at.force() = f / factor;
}
}
/* -------------------------------------------------------------------------- */
/* LMDESC RIGIDIFY
This stimulator allows to reduce the force acting over a set of degrees of
freedom to a single scalar and assign this last to all forces of that set.
Such a set will then act like a rigid body. More precisely the algorithm
is:\\
\begin{equation}
f_{global} = \sum_i f_i + f^{ext}
\end{equation}
\begin{equation}
f_i := \frac{f_{global}}{\#dof \cdot factor}
\end{equation}
where $\#dof$ is the number of dof in the subset $f^{ext}$ (GLOBAL\_FORCE) is
an external force
applied onto the rigid body and $factor$ (FACTOR) is a flexibility factor to
accelerate
linear motion.
*/
/* LMHERITATE action_interface */
/* LMEXAMPLE STIMULATION rigid RIGIDIFY INPUT md GLOBAL_FORCE 1 0 0 MASS_FACTOR
* 1e-3 */
//! most generic stimulate function
void StimulationRigidify::declareParams() {
StimulationInterface::declareParams();
this->changeDefault("STAGE", PRE_STEP3);
/* LMKEYWORD TOTAL_FORCE
Specifiy the external force to be applied to the rigid body.
*/
this->parseVectorKeyword("TOTAL_FORCE", spatial_dimension, total_force);
/* LMKEYWORD FACTOR
Correction factor to augment/reduce the forces applied to the rigid body.
*/
this->parseKeyword("FACTOR", factor, 1.);
}
/* -------------------------------------------------------------------------- */
DECLARE_STIMULATION_MAKE_CALL(StimulationRigidify)
__END_LIBMULTISCALE__
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