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tamaas/src/bem_polonski.cpp
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bem_polonski.cpp
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/**
*
* @author Guillaume Anciaux <guillaume.anciaux@epfl.ch>
*
* @section LICENSE
*
* Copyright (©) 2016 EPFL (Ecole Polytechnique Fédérale de
* Lausanne) Laboratory (LSMS - Laboratoire de Simulation en Mécanique des
* Solides)
*
* Tamaas 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.
*
* Tamaas 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 Tamaas. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include <vector>
#include "surface.hh"
#include "bem_polonski.hh"
#include "fft_plan_manager.hh"
#include "fftransform.hh"
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <sstream>
#include <cmath>
/* -------------------------------------------------------------------------- */
#define TIMER
#include "surface_timer.hh"
/* -------------------------------------------------------------------------- */
__BEGIN_TAMAAS__
BemPolonski::BemPolonski(Surface<Real> & p) :
BemFFTBase(p),
surface_t(p.size(),p.getL()),
surface_r(p.size(),p.getL()),
surface_spectral_r(p.size(),p.getL()),
pold(p.size(),p.getL()){
e_star = 1.;
max_iterations = 10000;
}
BemPolonski::~BemPolonski() {}
Real BemPolonski::computeEquilibrium(Real epsilon,
Real pressure){
this->computeSpectralInfluenceOverDisplacement();
this->surface_t = 0.;
this->surface_r = 0.;
this->surface_spectral_r = 0.;
this->pold = 0.;
this->surface_displacements = 0.;
Real delta = 0.;
Real Gold = 1.;
Real f = 1e300;
Real fPrevious = 1e300;
Real current_pressure = SurfaceStatistics::computeAverage(surface_tractions);
if (current_pressure <= 0.) surface_tractions = pressure;
this->enforcePressureBalance(pressure);
convergence_iterations.clear();
nb_iterations = 0;
while(f > epsilon && nb_iterations < max_iterations) {
fPrevious = f;
this->computeDisplacementsFromTractions();
this->computeGaps();
Real gbar = this->computeMeanGapsInContact();
this->gap -= gbar;
Real G = this->computeG();
//std::cout << "G vaut "<< G<< std::endl;
this->updateT(G,Gold,delta);
Real tau = this->computeTau();
pold = this->surface_tractions;
Gold = G;
delta = this->updateTractions(tau);
//Projection on admissible space
this->enforcePressureBalance(pressure);
f = this->computeF();
if (nb_iterations % dump_freq == 0){
Real A = SurfaceStatistics::computeContactAreaRatio(surface_tractions);
std::cout << std::scientific << std::setprecision(10)
<< nb_iterations << " "
<< f << " " << f-fPrevious << " " << A
<< std::endl;
}
convergence_iterations.push_back(f);
++nb_iterations;
}
return f;
}
/* -------------------------------------------------------------------------- */
void BemPolonski::computeGaps() {
UInt size = surface.size();
#pragma omp parallel for
for (UInt i=0; i < size*size; i++) {
gap(i) = surface_displacements(i) - surface(i);
}
}
/* -------------------------------------------------------------------------- */
Real BemPolonski::computeMeanGapsInContact(){
STARTTIMER("computeMeanGapsInContact");
UInt n = surface.size();
UInt size = n*n;
Real res = 0.;
UInt nb_contact = 0;
#pragma omp parallel for reduction(+: nb_contact,res)
for (UInt i = 0; i < size; ++i) {
if (this->surface_tractions(i) <= 0) continue;
++nb_contact;
res += this->gap(i);
}
res /= nb_contact;
STOPTIMER("computeMeanGapsInContact");
return res;
}
/* -------------------------------------------------------------------------- */
Real BemPolonski::computeG(){
STARTTIMER("computeG");
UInt n = surface.size();
UInt size = n*n;
Real res = 0.;
#pragma omp parallel for reduction(+: res)
for (UInt i = 0; i < size; ++i) {
if (this->surface_tractions(i) <= 0) continue;
Real val = this->gap(i);
res += val*val;
}
STOPTIMER("computeG");
return res;
}
/* -------------------------------------------------------------------------- */
void BemPolonski::updateT(Real G, Real Gold, Real delta){
STARTTIMER("updateT");
UInt n = surface.size();
UInt size = n*n;
Real factor = delta*G/Gold;
#pragma omp parallel for
for (UInt i = 0; i < size; ++i) {
if (this->surface_tractions(i) <= 0) this->surface_t(i) = 0.;
else{
this->surface_t(i) *= factor;
this->surface_t(i) += this->gap(i);
}
}
STOPTIMER("updateT");
}
/* -------------------------------------------------------------------------- */
Real BemPolonski::computeTau(){
STARTTIMER("computeTau");
surface_r = surface_t;
FFTransform<Real> & surface_r_transform =
FFTPlanManager::get().createPlan(surface_r, surface_spectral_r);
surface_r_transform.forwardTransform();
UInt n = surface.size();
UInt size = n*n;
#pragma omp parallel for
for (UInt i = 0; i < size; ++i) {
surface_spectral_r(i) *= this->surface_spectral_influence_disp(i);
}
surface_r_transform.backwardTransform();
Real rbar = 0;
UInt nb_contact = 0;
#pragma omp parallel for reduction(+: nb_contact,rbar)
for (UInt i = 0; i < size; ++i) {
if (this->surface_tractions(i) <= 0) continue;
++nb_contact;
rbar += surface_r(i);
}
rbar /= nb_contact;
surface_r -= rbar;
Real tau_sum1 = 0.,tau_sum2 = 0.;
#pragma omp parallel for reduction(+: tau_sum1, tau_sum2)
for (UInt i = 0; i < size; ++i) {
if (this->surface_tractions(i) <= 0) continue;
tau_sum1 += this->gap(i)*surface_t(i);
tau_sum2 += surface_r(i)*surface_t(i);
}
Real tau = tau_sum1/tau_sum2;
STOPTIMER("computeTau");
return tau;
}
/* -------------------------------------------------------------------------- */
Real BemPolonski::updateTractions(Real tau){
STARTTIMER("updateTractions");
UInt n = surface.size();
UInt size = n*n;
#pragma omp parallel for
for (UInt i = 0; i < size; ++i) {
if (this->surface_tractions(i) <= 0) continue;
this->surface_tractions(i) -= tau*this->surface_t(i);
if (this->surface_tractions(i) < 0.) this->surface_tractions(i) = 0;
}
//compute number of interpenetration without contact
UInt nb_iol = 0;
#pragma omp parallel for reduction(+: nb_iol)
for (UInt i = 0; i < size; ++i) {
if (this->surface_tractions(i) <= 0. &&
this->gap(i) < 0.){
this->surface_tractions(i) -= tau*this->gap(i);
++nb_iol;
}
}
Real delta = 0;
if (nb_iol > 0) delta = 0.;
else delta = 1.;
STOPTIMER("updateTractions");
return delta;
}
/* -------------------------------------------------------------------------- */
void BemPolonski::enforcePressureBalance(Real applied_pressure){
STARTTIMER("enforcePressureBalance");
UInt n = surface.size();
UInt size = n*n;
Real pressure = 0.;
#pragma omp parallel for reduction(+: pressure)
for (UInt i = 0; i < size; ++i) {
pressure += this->surface_tractions(i);
}
pressure *= 1./size;
for (UInt i = 0; i < size; ++i) {
this->surface_tractions(i) *= applied_pressure/pressure;
}
STOPTIMER("enforcePressureBalance");
}
/* -------------------------------------------------------------------------- */
Real BemPolonski::computeF() {
UInt n = surface.size();
UInt size = n*n;
Real res = 0;
Real d_max = SurfaceStatistics::computeMaximum(surface_displacements);
Real t_sum = std::abs(SurfaceStatistics::computeSum(surface_tractions));
Real s_max = SurfaceStatistics::computeMaximum(surface);
#pragma omp parallel for reduction(+:res)
for (UInt i = 0; i < size; ++i) {
res += std::abs(surface_tractions(i) * (surface_displacements(i)-d_max-surface(i)+s_max));
// res +=
// this->surface_tractions[i].real()
// *(surface_displacements[i].real() - surface[i].real());
}
return res/std::abs(t_sum);
}
/* -------------------------------------------------------------------------- */
__END_TAMAAS__
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