double StVKInternalForces::ComputeEnergyContribution(double * vertexDisplacements, int elementLow, int elementHigh, double * buffer)
{
if (buffer == NULL)
buffer = this->buffer;
int numVertices = volumetricMesh->getNumVertices();
double energy = 0;
// ---- linear
ResetVector(buffer);
AddLinearTermsContribution(vertexDisplacements, buffer, elementLow, elementHigh);
for (int i=0; i< 3 * numVertices; i++)
energy += 0.5 * buffer[i] * vertexDisplacements[i];
// ---- quadratic
ResetVector(buffer);
AddQuadraticTermsContribution(vertexDisplacements, buffer, elementLow, elementHigh);
double oneThird = 1.0 / 3;
for (int i=0; i< 3 * numVertices; i++)
energy += oneThird * buffer[i] * vertexDisplacements[i];
// ---- cubic
ResetVector(buffer);
AddCubicTermsContribution(vertexDisplacements, buffer, elementLow, elementHigh);
double oneQuarter = 1.0 / 4;
for (int i=0; i< 3 * numVertices; i++)
energy += oneQuarter * buffer[i] * vertexDisplacements[i];
return energy;
}
// the master function
void StVKStiffnessMatrix::ComputeStiffnessMatrix(double * vertexDisplacements, SparseMatrix * sparseMatrix)
{
//PerformanceCounter stiffnessCounter;
sparseMatrix->ResetToZero();
AddLinearTermsContribution(vertexDisplacements, sparseMatrix);
AddQuadraticTermsContribution(vertexDisplacements, sparseMatrix);
AddCubicTermsContribution(vertexDisplacements, sparseMatrix);
//stiffnessCounter.StopCounter();
//printf("Stiffness matrix: %G\n", stiffnessCounter.GetElapsedTime());
}
void StVKInternalForces::ComputeForces(double * vertexDisplacements, double * forces)
{
//PerformanceCounter forceCounter;
ResetVector(forces);
AddLinearTermsContribution(vertexDisplacements, forces);
AddQuadraticTermsContribution(vertexDisplacements, forces);
AddCubicTermsContribution(vertexDisplacements, forces);
if (addGravity)
{
int n = volumetricMesh->getNumVertices();
for(int i=0; i<3*n; i++)
forces[i] -= gravityForce[i];
}
//forceCounter.StopCounter();
//printf("Internal forces: %G\n", forceCounter.GetElapsedTime());
}
void StVKHessianTensor::ComputeStiffnessMatrixCorrection(double * u, double * du, SparseMatrix * dK)
{
dK->ResetToZero();
AddQuadraticTermsContribution(u, du, dK);
AddCubicTermsContribution(u, du, dK);
}
