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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 *
******************************************************************************/
#include <sofa/component/forcefield/TensorForceField.h>
#include <sofa/core/ObjectFactory.h>
#include <sofa/helper/system/gl.h>
#include <fstream> // for reading the file
#include <iostream> //for debugging
#include <sofa/defaulttype/Vec3Types.h>
using std::cerr;
using std::endl;
namespace sofa
{
namespace component
{
namespace forcefield
{
//dunnno how it was defined, but it works anyway...
static unsigned int vertexEdge[4][4]={{0,0,1,2,},{0,0,3,4},{1,3,0,5},{2,4,5,0}};
template <class DataTypes>
TensorForceField<DataTypes>::TensorForceField(const char* filename) {
load(filename);
initialize();
}
template <class DataTypes>
TensorForceField<DataTypes>::TensorForceField(
component::MechanicalObject<DataTypes>* object, const char* filename
)
: object_(object), alpha_(0.0), lambda_(2.80e5), mu_(3.1e4) {
load(filename);
initialize();
}
template<class DataTypes>
void
TensorForceField<DataTypes>::load(const char *filename) {
// opening the wrapping file
std::ifstream in(filename);
// read the young Modulues E and the Poisson coefficient nu and compute the
// lambda and mu lame coefficients from them
// TODO : change this to E and nu.
Real E, nu;
in >> E >> nu;
lambda_ = E * nu / ((1 + nu) * (1 - 2 * nu));
mu_ = E / (2 * (1 + nu));
// Read the damping factor alpha
in >> alpha_;
// read the name of the file containing the forcefield geometry
std::string filename2;
in >> filename2;
// we have all we need, so close the wrapping file
in.close();
std::ifstream input(filename2.c_str());
// read nb vertices and tetrahedra
unsigned int nbVertices,nbTetrahedra;
unsigned int dummyUInt;
input >> nbTetrahedra >> nbVertices;
// skips next 15 integers
for (int i = 0; i < 15; ++i)
input >> dummyUInt;
// read tetrahedra
unsigned int **vertexTetrahedronTable = new unsigned int * [nbTetrahedra];
for (unsigned int i = 0; i < nbTetrahedra; ++i)
vertexTetrahedronTable[i] = new unsigned int [4];
for (unsigned int i = 0; i < nbTetrahedra; ++i) {
for (int j = 0; j < 4; ++j) {
input >> vertexTetrahedronTable[i][j];
// the file indices are 1-based, so we convert them to a 0-base
--vertexTetrahedronTable[i][j];
}
}
// read vertices
Real px, py, pz;
for (unsigned int i = 0; i < nbVertices; ++i) {
input >> px >> py >> pz;
vertex_.push_back( Coord(px, py, pz) );
}
// we have read all we needed, so close the geometry file
input.close();
// defining tetrahedra
for (unsigned int i = 0; i < nbTetrahedra; ++i) {
Tetrahedron tetra;
tetra.vertex[0] = vertexTetrahedronTable[i][0];
tetra.vertex[1] = vertexTetrahedronTable[i][1];
tetra.vertex[2] = vertexTetrahedronTable[i][2];
tetra.vertex[3] = vertexTetrahedronTable[i][3];
// defining the edges of the current tetrahedron
for (int i = 1; i < 4; ++i) {
int v0 = tetra.vertex[i];
for (int j = 0; j < i; ++j) {
int v1 = tetra.vertex[j];
int e = getEdge(v0, v1);
tetra.edge[ vertexEdge[i][j] ] = e;
}
}
//defining the triangles of the current tetrahedron
for (int i = 0; i < 4; ++i) {
int v0 = tetra.vertex[(i+1)%4];
int v1 = tetra.vertex[(i+2)%4];
int v2 = tetra.vertex[(i+3)%4];
int tr = getTriangle(v0,v1,v2);
tetra.triangle[i] = tr;
}
tetra.index = tetrahedron_.size();
tetrahedron_.push_back(tetra);
}
// freeing allocated ressources
for (unsigned int i = 0; i < nbTetrahedra; ++i)
delete vertexTetrahedronTable[i];
delete vertexTetrahedronTable;
return;
}
template<class DataTypes>
void
TensorForceField<DataTypes>::initialize() {
// setting all tensors to null
for (unsigned int i = 0; i < vertex_.size(); ++i) {
vertexTensor_.push_back(VertexTensor());
vertexTensor_[i].resetToNull();
}
for (unsigned int i = 0; i < edge_.size(); ++i) {
edgeTensor_.push_back(EdgeTensor());
edgeTensor_[i].resetToNull();
}
// computing rest volume and triangles shapeVectors for all tetrahedrons
for (unsigned int i = 0; i < tetrahedron_.size(); ++i) {
Real a[3] = {vertex_[ tetrahedron_[i].vertex[0] ][0],
vertex_[ tetrahedron_[i].vertex[0] ][1],
vertex_[ tetrahedron_[i].vertex[0] ][2]};
Real b[3] = {vertex_[ tetrahedron_[i].vertex[1] ][0],
vertex_[ tetrahedron_[i].vertex[1] ][1],
vertex_[ tetrahedron_[i].vertex[1] ][2]};
Real c[3] = {vertex_[ tetrahedron_[i].vertex[2] ][0],
vertex_[ tetrahedron_[i].vertex[2] ][1],
vertex_[ tetrahedron_[i].vertex[2] ][2]};
Real d[3] = {vertex_[ tetrahedron_[i].vertex[3] ][0],
vertex_[ tetrahedron_[i].vertex[3] ][1],
vertex_[ tetrahedron_[i].vertex[3] ][2]};
Real ab[3] = {b[0] - a[0], b[1] - a[1], b[2] - a[2]};
Real ac[3] = {c[0] - a[0], c[1] - a[1], c[2] - a[2]};
Real ca[3] = {a[0] - c[0], a[1] - c[1], a[2] - c[2]};
Real ad[3] = {d[0] - a[0], d[1] - a[1], d[2] - a[2]};
Real bc[3] = {c[0] - b[0], c[1] - b[1], c[2] - b[2]};
Real cb[3] = {b[0] - c[0], b[1] - c[1], b[2] - c[2]};
Real bd[3] = {d[0] - b[0], d[1] - b[1], d[2] - b[2]};
// restVolume = dot(cross(ab, ac), ad) / 6.0
tetrahedron_[i].restVolume = ((ab[1] * ac[2] - ab[2] * ac[1]) * ad[0] +
(ab[2] * ac[0] - ab[0] * ac[2]) * ad[1] +
(ab[0] * ac[1] - ab[1] * ac[0]) * ad[2]) /
6.0f;
// tetrahedron_[i].triangleShapeVector[0] = cross (bc, bd)
tetrahedron_[i].triangleShapeVector[0][0] = bc[1] * bd[2] - bc[2] * bd[1];
tetrahedron_[i].triangleShapeVector[0][1] = bc[2] * bd[0] - bc[0] * bd[2];
tetrahedron_[i].triangleShapeVector[0][2] = bc[0] * bd[1] - bc[1] * bd[0];
// tetrahedron_[i].triangleShapeVector[0] = cross (ad, ac)
tetrahedron_[i].triangleShapeVector[1][0] = ad[1] * ac[2] - ad[2] * ac[1];
tetrahedron_[i].triangleShapeVector[1][1] = ad[2] * ac[0] - ad[0] * ac[2];
tetrahedron_[i].triangleShapeVector[1][2] = ad[0] * ac[1] - ad[1] * ac[0];
// tetrahedron_[i].triangleShapeVector[0] = cross (ab, ad)
tetrahedron_[i].triangleShapeVector[2][0] = ab[1] * ad[2] - ab[2] * ad[1];
tetrahedron_[i].triangleShapeVector[2][1] = ab[2] * ad[0] - ab[0] * ad[2];
tetrahedron_[i].triangleShapeVector[2][2] = ab[0] * ad[1] - ab[1] * ad[0];
// tetrahedron_[i].triangleShapeVector[0] = cross (cb, ca)
tetrahedron_[i].triangleShapeVector[0][0] = cb[1] * ca[2] - cb[2] * ca[1];
tetrahedron_[i].triangleShapeVector[0][1] = cb[2] * ca[0] - cb[0] * ca[2];
tetrahedron_[i].triangleShapeVector[0][2] = cb[0] * ca[1] - cb[1] * ca[0];
}
// initializing elastic tensors;
for (unsigned int i = 0; i < tetrahedron_.size(); ++i)
addElasticTensors( tetrahedron_[i] );
}
template<class DataTypes>
void
TensorForceField<DataTypes>::addForce () {
// getting the containing mechanical object's data
VecDeriv& f = *object_->getF();
const VecCoord& p = *object_->getX();
const VecDeriv& v = *object_->getV();
f.resize( p.size() ); // ??really needed??
// computing difference between current position and rest position
sofa::helper::vector< Coord > pos;
for (unsigned int i = 0; i < p.size(); ++i ) {
Coord dif = p[i] - vertex_[i];
pos.push_back(dif);
}
// la force au point i est egale a la matrice de raideur (tenseur) au
// point i * le deplacement du point i par rapport a sa position de repos plus
// la somme des matrices de raideur sur chacune des arretes partant du point i
// * le deplacement du point a l'autre bout de l'arrete.
// Adding vertices' contribution.
// TODO Check for sign correctness
for (unsigned int i = 0; i < vertex_.size(); ++i) {
f[i][0] -= vertexTensor_[i].tensor[0][0] * (pos[i][0] + alpha_ * v[i][0]) +
vertexTensor_[i].tensor[0][1] * (pos[i][1] + alpha_ * v[i][1]) +
vertexTensor_[i].tensor[0][2] * (pos[i][2] + alpha_ * v[i][2]);
f[i][1] -= vertexTensor_[i].tensor[1][0] * (pos[i][0] + alpha_ * v[i][0]) +
vertexTensor_[i].tensor[1][1] * (pos[i][1] + alpha_ * v[i][1]) +
vertexTensor_[i].tensor[1][2] * (pos[i][2] + alpha_ * v[i][2]);
f[i][2] -= vertexTensor_[i].tensor[2][0] * (pos[i][0] + alpha_ * v[i][0]) +
vertexTensor_[i].tensor[2][1] * (pos[i][1] + alpha_ * v[i][1]) +
vertexTensor_[i].tensor[2][2] * (pos[i][2] + alpha_ * v[i][2]);
}
// Adding edges' contribution.
// TODO Check for sign correctness
// TODO Check for transposition correctness
for (unsigned int i = 0; i < edge_.size(); ++i) {
int v0 = edge_[i].vertex[0];
int v1 = edge_[i].vertex[1];
f[v0][0] -= edgeTensor_[i].tensor[0][0] * (pos[v1][0] + alpha_ * v[v1][0]) +
edgeTensor_[i].tensor[1][0] * (pos[v1][1] + alpha_ * v[v1][1]) +
edgeTensor_[i].tensor[2][0] * (pos[v1][2] + alpha_ * v[v1][2]);
f[v0][1] -= edgeTensor_[i].tensor[0][1] * (pos[v1][0] + alpha_ * v[v1][0]) +
edgeTensor_[i].tensor[1][1] * (pos[v1][1] + alpha_ * v[v1][1]) +
edgeTensor_[i].tensor[2][1] * (pos[v1][2] + alpha_ * v[v1][2]);
f[v0][2] -= edgeTensor_[i].tensor[0][2] * (pos[v1][0] + alpha_ * v[v1][0]) +
edgeTensor_[i].tensor[1][2] * (pos[v1][1] + alpha_ * v[v1][1]) +
edgeTensor_[i].tensor[2][2] * (pos[v1][2] + alpha_ * v[v1][2]);
f[v1][0] -= edgeTensor_[i].tensor[0][0] * (pos[v0][0] + alpha_ * v[v0][0]) +
edgeTensor_[i].tensor[0][1] * (pos[v0][1] + alpha_ * v[v0][1]) +
edgeTensor_[i].tensor[0][2] * (pos[v0][2] + alpha_ * v[v0][2]);
f[v1][1] -= edgeTensor_[i].tensor[1][0] * (pos[v0][0] + alpha_ * v[v0][0]) +
edgeTensor_[i].tensor[1][1] * (pos[v0][1] + alpha_ * v[v0][1]) +
edgeTensor_[i].tensor[1][2] * (pos[v0][2] + alpha_ * v[v0][2]);
f[v1][2] -= edgeTensor_[i].tensor[2][0] * (pos[v0][0] + alpha_ * v[v0][0]) +
edgeTensor_[i].tensor[2][1] * (pos[v0][1] + alpha_ * v[v0][1]) +
edgeTensor_[i].tensor[2][2] * (pos[v0][2] + alpha_ * v[v0][2]);
}
}
template<class DataTypes>
void
TensorForceField<DataTypes>::addDForce() {
// getting the containing mechanical object's data
VecDeriv& f = *object_->getF();
// use Dx instead of X
const VecCoord& p = *object_->getDx();
const VecDeriv& v = *object_->getV();
f.resize( p.size() ); // ??really needed??
// computing difference between current position and rest position
/*sofa::helper::vector< Coord > pos;
for (unsigned int i = 0; i < p.size(); ++i ) {
Coord dif = p[i] - vertex_[i];
pos.push_back(dif);
}*/
// la force au point i est egale a la matrice de raideur (tenseur) au
// point i * le deplacement du point i par rapport a sa position de repos plus
// la somme des matrices de raideur sur chacune des arretes partant du point i
// * le deplacement du point a l'autre bout de l'arrete.
// Adding vertices' contribution.
// TODO Check for sign correctness
for (unsigned int i = 0; i < vertex_.size(); ++i) {
f[i][0] -= vertexTensor_[i].tensor[0][0] * (p[i][0] + alpha_ * v[i][0]) +
vertexTensor_[i].tensor[0][1] * (p[i][1] + alpha_ * v[i][1]) +
vertexTensor_[i].tensor[0][2] * (p[i][2] + alpha_ * v[i][2]);
f[i][1] -= vertexTensor_[i].tensor[1][0] * (p[i][0] + alpha_ * v[i][0]) +
vertexTensor_[i].tensor[1][1] * (p[i][1] + alpha_ * v[i][1]) +
vertexTensor_[i].tensor[1][2] * (p[i][2] + alpha_ * v[i][2]);
f[i][2] -= vertexTensor_[i].tensor[2][0] * (p[i][0] + alpha_ * v[i][0]) +
vertexTensor_[i].tensor[2][1] * (p[i][1] + alpha_ * v[i][1]) +
vertexTensor_[i].tensor[2][2] * (p[i][2] + alpha_ * v[i][2]);
}
// Adding edges' contribution.
// TODO Check for sign correctness
// TODO Check for transposition correctness
for (unsigned int i = 0; i < edge_.size(); ++i) {
int v0 = edge_[i].vertex[0];
int v1 = edge_[i].vertex[1];
f[v0][0] -= edgeTensor_[i].tensor[0][0] * (p[v1][0] + alpha_ * v[v1][0]) +
edgeTensor_[i].tensor[1][0] * (p[v1][1] + alpha_ * v[v1][1]) +
edgeTensor_[i].tensor[2][0] * (p[v1][2] + alpha_ * v[v1][2]);
f[v0][1] -= edgeTensor_[i].tensor[0][1] * (p[v1][0] + alpha_ * v[v1][0]) +
edgeTensor_[i].tensor[1][1] * (p[v1][1] + alpha_ * v[v1][1]) +
edgeTensor_[i].tensor[2][1] * (p[v1][2] + alpha_ * v[v1][2]);
f[v0][2] -= edgeTensor_[i].tensor[0][2] * (p[v1][0] + alpha_ * v[v1][0]) +
edgeTensor_[i].tensor[1][2] * (p[v1][1] + alpha_ * v[v1][1]) +
edgeTensor_[i].tensor[2][2] * (p[v1][2] + alpha_ * v[v1][2]);
f[v1][0] -= edgeTensor_[i].tensor[0][0] * (p[v0][0] + alpha_ * v[v0][0]) +
edgeTensor_[i].tensor[0][1] * (p[v0][1] + alpha_ * v[v0][1]) +
edgeTensor_[i].tensor[0][2] * (p[v0][2] + alpha_ * v[v0][2]);
f[v1][1] -= edgeTensor_[i].tensor[1][0] * (p[v0][0] + alpha_ * v[v0][0]) +
edgeTensor_[i].tensor[1][1] * (p[v0][1] + alpha_ * v[v0][1]) +
edgeTensor_[i].tensor[1][2] * (p[v0][2] + alpha_ * v[v0][2]);
f[v1][2] -= edgeTensor_[i].tensor[2][0] * (p[v0][0] + alpha_ * v[v0][0]) +
edgeTensor_[i].tensor[2][1] * (p[v0][1] + alpha_ * v[v0][1]) +
edgeTensor_[i].tensor[2][2] * (p[v0][2] + alpha_ * v[v0][2]);
}
}
template <class DataTypes>
double TensorForceField<DataTypes>::getPotentialEnergy()
{
cerr<<"TensorForceField::getPotentialEnergy-not-implemented !!!"<<endl;
return 0;
}
template<class DataTypes>
void TensorForceField<DataTypes>::draw() {
if (!getContext()->getShowForceFields()) return;
const VecCoord& p1 = *object_->getX();
glDisable(GL_LIGHTING);
glColor4f(1,1,1,1);
glBegin(GL_LINES);
for (unsigned int i = 0; i < edge_.size(); ++i) {
glVertex3d(p1[edge_[i].vertex[0]][0],
p1[edge_[i].vertex[0]][1],
p1[edge_[i].vertex[0]][2]);
glVertex3d(p1[edge_[i].vertex[1]][0],
p1[edge_[i].vertex[1]][1],
p1[edge_[i].vertex[1]][2]);
}
glEnd();
}
template<class DataTypes>
void TensorForceField<DataTypes>::initTextures() {
}
template<class DataTypes>
void TensorForceField<DataTypes>::update() {
}
// search for the edge connecting the given vertices, create it if not found
template<class DataTypes>
int
TensorForceField<DataTypes>::getEdge(const int v0, const int v1) {
for (unsigned int i = 0; i < edge_.size(); ++i) {
if (
(edge_[i].vertex[0] == v0 && edge_[i].vertex[1] == v1) ||
(edge_[i].vertex[0] == v1 && edge_[i].vertex[1] == v0)
)
return i;
}
// edge wasn't found, we have to create it
Edge e;
e.index = edge_.size();
e.vertex[0] = v0;
e.vertex[1] = v1;
edge_.push_back(e);
return e.index;
}
// search for the triangle connecting the given vertices, create it if not found
template<class DataTypes>
int
TensorForceField<DataTypes>::getTriangle(const int v0, const int v1,
const int v2) {
for (unsigned int i = 0; i < triangle_.size(); ++i) {
int tv0 = triangle_[i].vertex[0];
int tv1 = triangle_[i].vertex[1];
int tv2 = triangle_[i].vertex[2];
if (
(tv0 == v0 && tv1 == v1 && tv2 == v2) ||
(tv0 == v0 && tv1 == v2 && tv2 == v1) ||
(tv0 == v1 && tv1 == v0 && tv2 == v2) ||
(tv0 == v1 && tv1 == v2 && tv2 == v0) ||
(tv0 == v2 && tv1 == v0 && tv2 == v1) ||
(tv0 == v2 && tv1 == v1 && tv2 == v0)
)
return i;
}
// triangle wasn't found, we have to create it
Triangle t;
t.index = triangle_.size();
t.vertex[0] = v0;
t.vertex[1] = v1;
t.vertex[2] = v2;
triangle_.push_back(t);
return t.index;
}
// add the elastic tensors for the given tetrahedron
template<class DataTypes>
void TensorForceField<DataTypes>::addElasticTensors(Tetrahedron& tetra) {
Real si[3];
Real sj[3];
Real t[3][3];
Real id[3][3] = {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}};
for (int i = 0; i < 4; ++i) {
for (int j = i; j < 4; ++j) {
// si is the shape vector of triangle[i]
si[0] = tetra.triangleShapeVector[i][0];
si[1] = tetra.triangleShapeVector[i][1];
si[2] = tetra.triangleShapeVector[i][2];
// sj is the shape vector of triangle[j]
sj[0] = tetra.triangleShapeVector[j][0];
sj[1] = tetra.triangleShapeVector[j][1];
sj[2] = tetra.triangleShapeVector[j][2];
Real dot = (si[0] * sj[0]) + (si[1] * sj[1]) + (si[2] * sj[2]);
// mij is the tensor product of si sj
Real mij[3][3] = {{si[0] * sj[0], si[0] * sj[1], si[0] * sj[2]},
{si[1] * sj[0], si[1] * sj[1], si[1] * sj[2]},
{si[2] * sj[0], si[2] * sj[1], si[2] * sj[2]}};
Real mijTransp[3][3] = {{si[0] * sj[0], si[1] * sj[0], si[2] * sj[0]},
{si[0] * sj[1], si[1] * sj[1], si[2] * sj[1]},
{si[0] * sj[2], si[1] * sj[2], si[2] * sj[2]}};
// t is the edge or vertex tensor
for (int k = 0; k < 3; ++k) {
for (int l = 0; l < 3; ++l) {
t[k][l] = lambda_ * mij[k][l] +
mu_ * ( mijTransp[k][l] + dot * id[k][l] );
// divide by (6.0 * volume)^2 to get the real shape vectors in the
// products ( (x) -> ^2) and multiplied by volume from the volumetric
// integration
t[k][l] /= 36.0f * tetra.restVolume;
}
}
// add t to the tensor stored in edges or vertices
if (i==j) {
// t is the tensor for the vertex
for (int k = 0; k < 3; ++k) {
for (int l = 0; l < 3; ++l) {
vertexTensor_[tetra.vertex[i]].tensor[k][l] += t[k][l];
}
}
}
else {
// t (or its transposed, depending on the tetrahedron orientation) is
// the tensor for the edge.
if ( edge_[ tetra.edge[ vertexEdge[i][j] ] ].vertex[0] ==
tetra.vertex[i] ) {
for (int k = 0; k < 3; ++k) {
for (int l = 0; l < 3; ++l) {
edgeTensor_[tetra.edge[vertexEdge[i][j]]].tensor[k][l]+= t[k][l];
}
}
}
else {
for (int k = 0; k < 3; ++k) {
for (int l = 0; l < 3; ++l) {
edgeTensor_[tetra.edge[vertexEdge[i][j]]].tensor[k][l]+= t[l][k];
}
}
}
}
}
}
}
//--- the following seems to be needed for factory registering
SOFA_DECL_CLASS(TensorForceField)
using namespace sofa::defaulttype;
template<class DataTypes>
void create(TensorForceField<DataTypes>*& obj,
simulation::tree::xml::ObjectDescription* arg) {
simulation::tree::xml::createWithParentAndFilename<
TensorForceField<DataTypes>, component::MechanicalObject<DataTypes>
> (obj, arg);
}
#ifndef SOFA_FLOAT
Creator<simulation::tree::xml::ObjectFactory, TensorForceField<Vec3dTypes> >
TensorForceFieldVec3dClass("TensorForceField", true);
template class TensorForceField<Vec3dTypes>;
#endif
#ifndef SOFA_DOUBLE
Creator<simulation::tree::xml::ObjectFactory, TensorForceField<Vec3fTypes> >
TensorForceFieldVec3fClass("TensorForceField", true);
template class TensorForceField<Vec3fTypes>; // doesn't work for now
#endif
} // namespace forcefield
} // namespace component
} // namespace sofa
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