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bem_gigi.cpp
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Wed, Jul 10, 04:10

bem_gigi.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_gigi.hh"
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <sstream>
#include <cmath>
/* -------------------------------------------------------------------------- */
#define TIMER
#include "surface_timer.hh"
/* -------------------------------------------------------------------------- */
Real BemGigi::computeEquilibrium(Real epsilon,
Real pressure,
int nthreads){
this->setNumberOfThreads(nthreads);
this->computeSpectralInfluenceOverDisplacement();
this->surface_t = 0.;
this->surface_r = 0.;
this->surface_spectral_r = 0.;
this->surface_w = 0.;
this->surface_q = 0.;
this->surface_spectral_q = 0.;
this->pold = 0.;
this->surface_displacements = 0.;
Real Gold = 1.;
Real Rold = 1.;
Real tau = 0.;
Real f = 1e300;
Real fPrevious = 1e300;
// Real current_pressure = SurfaceStatistics::computeAverage(surface_tractions);
surface_tractions = pressure;
this->enforcePressureBalance(pressure);
convergence_iterations.clear();
nb_iterations = 0;
while(f > epsilon && nb_iterations < max_iterations) {
++nb_iterations;
fPrevious = f;
this->computeDisplacements();
this->functional->computeGradF();
this->functional->centerGradFOnContactArea();
Real R = this->computeR();
this->updateW(R,Rold);
Real alpha = this->computeAlpha();
pold = this->surface_tractions;
Rold = R;
Gold = R;
this->updatePressurea(alpha);
tau=alpha;
this->computeGaps();
UInt Iol=this->computeIol();
Real G = this->computeG();
//Inner loop
while(G > epsilon) {
++nb_iterations;
this->emptyoverlap(tau);
this->enforcePressureBalance(pressure);
this->functional->computeF();
f = this->functional->getF();
fPrevious = f;
this->computeDisplacements();
this->computeGaps();
Real gbar = this->computeMeanGapsInContact();
this->gap -= gbar;
G = this->computeG();
this->updateT(G,Gold);
Real tau = this->computeTau();
pold = this->surface_tractions;
Gold = G;
this->updatePressureb(tau);
Iol= this->computeIol();
}
this->enforcePressureBalance(pressure);
this->functional->computeF();
f = this->functional->getF();
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);
}
return f;
}
/* -------------------------------------------------------------------------- */
void BemGigi::truncatePressure(){
STARTTIMER("truncatePressure");
unsigned int n = surface.size();
unsigned int size = n*n;
#pragma omp parallel for
for (unsigned int i = 0; i < size; ++i) {
if (this->surface_tractions(i) < 0.) this->surface_tractions(i) = 0;
}
STOPTIMER("truncatePressure");
}
/* -------------------------------------------------------------------------- */
Real BemGigi::computeR(){
STARTTIMER("computeR");
unsigned int n = surface.size();
unsigned int size = n*n;
Real res = 0.;
Surface<Real> & gradF = this->functional->getGradF();
#pragma omp parallel for reduction(+: res)
for (unsigned int i = 0; i < size; ++i) {
Real val = gradF(i);
res += val*val;
}
STOPTIMER("computeR");
return res;
}
/* -------------------------------------------------------------------------- */
Real BemGigi::computeIol(){
STARTTIMER("computeIol");
unsigned int n = surface.size();
unsigned int size = n*n;
UInt Iol = 0;
#pragma omp parallel for
for (unsigned int i = 0; i < size; ++i) {
if (this->surface_tractions(i) <= 0. && this->gap(i) < 0.){
++Iol;}
}
STOPTIMER("Iol");
return Iol;
}
/* -------------------------------------------------------------------------- */
void BemGigi::updateW(Real R, Real Rold){
STARTTIMER("updateW");
unsigned int n = surface.size();
unsigned int size = n*n;
Real factor = R/Rold;
Surface<Real> & gradF = this->functional->getGradF();
#pragma omp parallel for
for (unsigned int i = 0; i < size; ++i) {
this->surface_w(i) *= factor;
this->surface_w(i) += gradF(i);
}
STOPTIMER("updateW");
}
/* -------------------------------------------------------------------------- */
void BemGigi::updateT(Real G, Real Gold){
STARTTIMER("updateT");
unsigned int n = surface.size();
unsigned int size = n*n;
Real factor = G/Gold;
#pragma omp parallel for
for (unsigned int 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 BemGigi::computeAlpha(){
STARTTIMER("computeAlpha");
surface_spectral_q = surface_w;
surface_spectral_q.FFTTransform(nthreads);
unsigned int n = surface.size();
unsigned int size = n*n;
#pragma omp parallel for
for (unsigned int i = 0; i < size; ++i) {
surface_spectral_q(i) *= this->surface_spectral_influence_disp(i);
}
surface_spectral_q.FFTITransform(surface_q,nthreads);
Real qbar = 0;
UInt nb_contact = 0;
#pragma omp parallel for reduction(+: nb_contact,qbar)
for (unsigned int i = 0; i < size; ++i) {
++nb_contact;
qbar += surface_q(i);
}
qbar /= nb_contact;
surface_q -= qbar;
Real alpha_sum1 = 0.,alpha_sum2 = 0.;
Surface<Real> & gradF = this->functional->getGradF();
#pragma omp parallel for reduction(+: alpha_sum1, alpha_sum2)
for (unsigned int i = 0; i < size; ++i) {
alpha_sum1 += gradF(i)*surface_w(i);
alpha_sum2 += surface_q(i)*surface_w(i);
}
Real alpha = alpha_sum1/alpha_sum2;
STOPTIMER("computeAlpha");
return alpha;
}
/* -------------------------------------------------------------------------- */
void BemGigi::updatePressurea(Real alpha ){
STARTTIMER("updatePressurea");
unsigned int n = surface.size();
unsigned int size = n*n;
#pragma omp parallel for
for (unsigned int i = 0; i < size; ++i) {
this->surface_tractions(i) -= alpha*this->surface_w(i);
}
STOPTIMER("updatePressurea");
}
/* -------------------------------------------------------------------------- */
void BemGigi::updatePressureb(Real tau ){
STARTTIMER("updatePressureb");
unsigned int n = surface.size();
unsigned int size = n*n;
#pragma omp parallel for
for (unsigned int i = 0; i < size; ++i) {
if (this->surface_tractions(i) <= 0) continue;
this->surface_tractions(i) -= tau*this->surface_t(i);
}
STOPTIMER("updatePressureb");
}
/* -------------------------------------------------------------------------- */
void BemGigi::emptyoverlap(Real tau){
STARTTIMER("emptyoverlap");
unsigned int n = surface.size();
unsigned int size = n*n;
#pragma omp parallel for
for (unsigned int i = 0; i < size; ++i) {
if (this->surface_tractions(i) <= 0. && this->gap(i) < 0.){
this->surface_tractions(i) = -this->surface_tractions(i)-tau*this->gap(i); }
}
STOPTIMER("emptyoverlap");
}
/* -------------------------------------------------------------------------- */
void BemGigi::enforcePressureBalance(Real applied_pressure){
STARTTIMER("enforcePressureBalance");
unsigned int n = surface.size();
unsigned int size = n*n;
Real pressure = 0.;
#pragma omp parallel for reduction(+: pressure)
for (unsigned int i = 0; i < size; ++i) {
pressure += this->surface_tractions(i);
}
pressure *= 1./size;
// std::cerr << std::scientific << std::setprecision(10)
// << "pressure " << pressure << std::endl;
#pragma omp parallel for
for (unsigned int i = 0; i < size; ++i) {
this->surface_tractions(i) *= applied_pressure/pressure;
}
STOPTIMER("enforcePressureBalance");
}
/* -------------------------------------------------------------------------- */
/* -------------------------------------------------------------------------- */
void BemGigi::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 BemGigi::computeMeanGapsInContact(){
STARTTIMER("computeMeanGapsInContact");
unsigned int n = surface.size();
unsigned int size = n*n;
Real res = 0.;
UInt nb_contact = 0;
#pragma omp parallel for reduction(+: nb_contact,res)
for (unsigned int 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 BemGigi::computeG(){
STARTTIMER("computeG");
unsigned int n = surface.size();
unsigned int size = n*n;
Real res = 0.;
#pragma omp parallel for reduction(+: res)
for (unsigned int i = 0; i < size; ++i) {
if (this->surface_tractions(i) <= 0) continue;
Real val = this->gap(i);
res += val*val;
}
// std::cout << res << std::endl;
STOPTIMER("computeG");
return res;
}
/* -------------------------------------------------------------------------- */
Real BemGigi::computeTau(){
STARTTIMER("computeTau");
surface_spectral_r = surface_t;
surface_spectral_r.FFTTransform(nthreads);
unsigned int n = surface.size();
unsigned int size = n*n;
#pragma omp parallel for
for (unsigned int i = 0; i < size; ++i) {
surface_spectral_r(i) *= this->surface_spectral_influence_disp(i);
}
surface_spectral_r.FFTITransform(surface_r,nthreads);
Real rbar = 0;
UInt nb_contact = 0;
#pragma omp parallel for reduction(+: nb_contact,rbar)
for (unsigned int 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 (unsigned int 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;
}

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