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rTAMAAS tamaas
bem_gigipol.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_gigipol.hh"
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <sstream>
#include <cmath>
/* -------------------------------------------------------------------------- */
#define TIMER
#include "surface_timer.hh"
/* -------------------------------------------------------------------------- */
__BEGIN_TAMAAS__
void
BemGigipol
::
computeTractionsFromDisplacements
()
{
this
->
applyInverseInfluenceFunctions
(
this
->
true_displacements
,
this
->
surface_tractions
);
}
Real
BemGigipol
::
computeEquilibrium
(
Real
epsilon
,
Real
mean_displacement
)
{
this
->
computeSpectralInfluenceOverDisplacement
();
this
->
surface_t
=
0.
;
this
->
surface_r
=
0.
;
this
->
search_direction
=
0.
;
this
->
pold
=
0.
;
this
->
surface_displacements
=
0.
;
Real
delta
=
0.
;
Real
Gold
=
1.
;
Real
f
=
1e300
;
Real
fPrevious
=
1e300
;
UInt
n
=
surface
.
size
();
UInt
size
=
n
*
n
;
this
->
true_displacements
=
0
;
//this->true_displacements = SurfaceStatistics::computeAverage(surface, 0);
this
->
computeGaps
();
this
->
optimizeToMeanDisplacement
(
mean_displacement
);
this
->
computeGaps
();
convergence_iterations
.
clear
();
nb_iterations
=
0
;
max_iterations
=
5000
;
while
(
f
>
epsilon
&&
nb_iterations
<
max_iterations
)
{
fPrevious
=
f
;
this
->
functional
->
computeGradFU
();
this
->
search_direction
=
this
->
functional
->
getGradF
();
Real
gbar
=
this
->
computeMeanPressuresInNonContact
();
this
->
search_direction
-=
gbar
;
Real
G
=
this
->
computeG
();
this
->
updateT
(
G
,
Gold
,
delta
);
Real
tau
=
this
->
computeTau
();
this
->
old_displacements
=
this
->
true_displacements
;
Gold
=
G
;
#pragma omp parallel for
for
(
unsigned
int
i
=
0
;
i
<
size
;
++
i
)
{
this
->
true_displacements
(
i
)
-=
tau
*
this
->
surface_t
(
i
);
}
//Projection on admissible space
this
->
computeGaps
();
#pragma omp parallel for
for
(
unsigned
int
i
=
0
;
i
<
size
;
++
i
)
{
if
(
this
->
gap
(
i
)
<
0
){
this
->
true_displacements
(
i
)
=
this
->
surface
(
i
);}
}
this
->
computeGaps
();
delta
=
this
->
updateDisplacements
(
tau
,
mean_displacement
);
//Projection on admissible space
this
->
computeGaps
();
this
->
enforceMeanDisplacement
(
mean_displacement
);
this
->
computeGaps
();
this
->
computePressures
();
f
=
this
->
computeStoppingCriterion
();
if
(
nb_iterations
%
dump_freq
==
0
){
std
::
cout
<<
"G vaut "
<<
G
<<
std
::
endl
;
std
::
cout
<<
"f vaut "
<<
f
<<
std
::
endl
;
std
::
cout
<<
std
::
scientific
<<
std
::
setprecision
(
10
)
<<
nb_iterations
<<
" "
<<
f
<<
" "
<<
f
-
fPrevious
<<
" "
<<
'G'
<<
" "
<<
G
<<
" "
<<
std
::
endl
;
}
convergence_iterations
.
push_back
(
f
);
++
nb_iterations
;
}
this
->
computePressures
();
return
f
;
}
/* -------------------------------------------------------------------------- */
Real
BemGigipol
::
computeStoppingCriterion
()
{
UInt
n
=
surface
.
size
();
UInt
size
=
n
*
n
;
Real
res
=
0
;
Real
t_sum
=
std
::
abs
(
SurfaceStatistics
::
computeSum
(
this
->
true_displacements
));
this
->
computeTractionsFromDisplacements
();
this
->
functional
->
computeGradFU
();
const
Surface
<
Real
>
&
gradF
=
this
->
functional
->
getGradF
();
Real
min
=
SurfaceStatistics
::
computeMinimum
(
gradF
);
#pragma omp parallel for reduction(+:res)
for
(
UInt
i
=
0
;
i
<
size
;
++
i
)
{
res
+=
std
::
abs
((
gradF
(
i
)
-
min
)
*
(
this
->
true_displacements
(
i
)
-
surface
(
i
)));
// res +=
// this->surface_tractions[i].real()
// *(surface_displacements[i].real() - surface[i].real());
}
return
res
/
std
::
abs
(
t_sum
);
}
/* -------------------------------------------------------------------------- */
Real
BemGigipol
::
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
->
gap
(
i
)
>
0.
)
{
Real
val
=
this
->
search_direction
(
i
);
res
+=
val
*
val
;}
}
STOPTIMER
(
"computeG"
);
return
res
;
}
/* -------------------------------------------------------------------------- */
/* -------------------------------------------------------------------------- */
Real
BemGigipol
::
computeMeanPressuresInNonContact
(){
STARTTIMER
(
"computeMeanPressuresInNonContact"
);
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
->
gap
(
i
)
==
0.
)
continue
;
++
nb_contact
;
res
+=
this
->
search_direction
(
i
);
}
res
/=
nb_contact
;
STOPTIMER
(
"computeMeanPressuresInNonContact"
);
return
res
;
}
/* -------------------------------------------------------------------------- */
void
BemGigipol
::
optimizeToMeanDisplacement
(
Real
imposed_mean
)
{
Real
target_value
=
imposed_mean
-
SurfaceStatistics
::
computeAverage
(
surface
,
0
);
UInt
n
=
surface
.
size
();
UInt
size
=
n
*
n
;
// Initial guesses for upper and lower bound
Real
step_min
=
-
10
;
Real
step_max
=
10
;
// Gaps for upper and lower bound
Real
gap_min
=
positiveGapAverage
(
step_min
);
Real
gap_max
=
positiveGapAverage
(
step_max
);
UInt
max_expansion
=
8
;
// Expand bounds if necessary
for
(
UInt
i
=
0
;
gap_max
<
target_value
&&
i
<
max_expansion
;
i
++
,
step_max
*=
10
)
gap_max
=
positiveGapAverage
(
step_max
);
for
(
UInt
i
=
0
;
gap_min
>
target_value
&&
i
<
max_expansion
;
i
++
,
step_min
*=
10
)
gap_min
=
positiveGapAverage
(
step_min
);
Real
g
=
0.
;
Real
epsilon
=
1e-12
;
Real
step
=
0
;
while
(
fabs
(
g
-
target_value
)
>
epsilon
)
{
step
=
(
step_min
+
step_max
)
/
2.
;
g
=
positiveGapAverage
(
step
);
if
(
g
>
target_value
)
step_max
=
step
;
else
if
(
g
<
target_value
)
step_min
=
step
;
else
{
step_max
=
step
;
step_min
=
step
;
}
}
step
=
(
step_min
+
step_max
)
/
2.
;
#pragma omp parallel for
for
(
UInt
i
=
0
;
i
<
size
;
i
++
)
{
gap
(
i
)
+=
step
;
if
(
gap
(
i
)
<
0
)
gap
(
i
)
=
0
;
true_displacements
(
i
)
=
gap
(
i
)
+
surface
(
i
);
}
}
/* -------------------------------------------------------------------------- */
Real
BemGigipol
::
positiveGapAverage
(
Real
shift
)
{
UInt
n
=
surface
.
size
();
Real
res
=
0
;
#pragma omp parallel for reduction(+: res)
for
(
UInt
i
=
0
;
i
<
n
*
n
;
i
++
)
{
Real
shifted_gap
=
gap
(
i
)
+
shift
;
res
+=
shifted_gap
*
(
shifted_gap
>
0
);
}
return
res
/
(
n
*
n
);
}
/* -------------------------------------------------------------------------- */
void
BemGigipol
::
updateT
(
Real
G
,
Real
Gold
,
Real
delta
){
STARTTIMER
(
"updateT"
);
unsigned
int
n
=
surface
.
size
();
unsigned
int
size
=
n
*
n
;
Real
factor
=
delta
*
G
/
Gold
;
#pragma omp parallel for
for
(
unsigned
int
i
=
0
;
i
<
size
;
++
i
)
{
if
(
this
->
gap
(
i
)
==
0.
)
this
->
surface_t
(
i
)
=
0.
;
else
{
this
->
surface_t
(
i
)
*=
factor
;
this
->
surface_t
(
i
)
+=
this
->
search_direction
(
i
);
}
}
STOPTIMER
(
"updateT"
);
}
/* -------------------------------------------------------------------------- */
Real
BemGigipol
::
computeTau
()
{
STARTTIMER
(
"computeOptimalStep"
);
const
UInt
n
=
surface
.
size
();
const
UInt
size
=
n
*
n
;
this
->
applyInverseInfluenceFunctions
(
surface_t
,
surface_r
);
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
->
gap
(
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
->
gap
(
i
)
==
0
)
continue
;
tau_sum1
+=
this
->
search_direction
(
i
)
*
surface_t
(
i
);
tau_sum2
+=
surface_r
(
i
)
*
surface_t
(
i
);
}
Real
tau
=
tau_sum1
/
tau_sum2
;
STOPTIMER
(
"computeTau"
);
return
tau
;
}
/* -------------------------------------------------------------------------- */
Real
BemGigipol
::
updateDisplacements
(
Real
tau
,
Real
mean_displacement
)
{
STARTTIMER
(
"updateDisplacements"
);
unsigned
int
n
=
surface
.
size
();
unsigned
int
size
=
n
*
n
;
//compute number of interpenetration without contact
UInt
nb_iol
=
0
;
#pragma omp parallel for reduction(+: nb_iol)
for
(
unsigned
int
i
=
0
;
i
<
size
;
++
i
)
{
if
(
this
->
search_direction
(
i
)
<
0
&&
this
->
gap
(
i
)
==
0.
){
this
->
true_displacements
(
i
)
-=
tau
*
this
->
search_direction
(
i
);
++
nb_iol
;
}
}
Real
delta
=
0
;
if
(
nb_iol
>
0
)
delta
=
0.
;
else
delta
=
1.
;
return
delta
;
STOPTIMER
(
"updateDisplacements"
);
}
/* -------------------------------------------------------------------------- */
void
BemGigipol
::
enforceMeanDisplacement
(
Real
mean_displacement
)
{
STARTTIMER
(
"enforceMeanDisplacement"
);
UInt
n
=
surface
.
size
();
UInt
size
=
n
*
n
;
Real
moyenne_surface
=
SurfaceStatistics
::
computeAverage
(
this
->
surface
,
0
);
Real
average
=
SurfaceStatistics
::
computeAverage
(
this
->
true_displacements
,
0
);
Real
factor
=
(
mean_displacement
-
moyenne_surface
)
/
(
average
-
moyenne_surface
);
#pragma omp parallel for
for
(
UInt
i
=
0
;
i
<
size
;
++
i
)
{
this
->
true_displacements
(
i
)
=
factor
*
(
this
->
true_displacements
(
i
)
-
this
->
surface
(
i
))
+
this
->
surface
(
i
);
}
STOPTIMER
(
"enforceMeanDisplacement"
);
}
/* -------------------------------------------------------------------------- */
void
BemGigipol
::
computePressures
()
{
this
->
computeTractionsFromDisplacements
();
this
->
functional
->
computeGradFU
();
const
Surface
<
Real
>
&
gradF
=
this
->
functional
->
getGradF
();
Real
min
=
SurfaceStatistics
::
computeMinimum
(
gradF
);
this
->
surface_tractions
-=
min
;
}
/* -------------------------------------------------------------------------- */
__END_TAMAAS__
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