void
IntElLine1PhF :: computeCovarBaseVectorAt(IntegrationPoint *ip, FloatArray &G)
{
FloatMatrix dNdxi;
FEInterpolation *interp = this->giveInterpolation();
interp->evaldNdxi( dNdxi, ip->giveNaturalCoordinates(), FEIElementGeometryWrapper(this) );
G.resize(2);
G.zero();
int numNodes = this->giveNumberOfNodes();
for ( int i = 1; i <= dNdxi.giveNumberOfRows(); i++ ) {
double X1_i = 0.5 * ( this->giveNode(i)->giveCoordinate(1) + this->giveNode(i + numNodes / 2)->giveCoordinate(1) ); // (mean) point on the fictious mid surface
double X2_i = 0.5 * ( this->giveNode(i)->giveCoordinate(2) + this->giveNode(i + numNodes / 2)->giveCoordinate(2) );
G.at(1) += dNdxi.at(i, 1) * X1_i;
G.at(2) += dNdxi.at(i, 1) * X2_i;
}
}
void
IntElLine2IntPen :: computeCovarBaseVectorAt(IntegrationPoint *ip, FloatArray &G)
{
// printf("Entering IntElLine2IntPen :: computeCovarBaseVectorAt\n");
// Since we are averaging over the whole element, always evaluate the base vectors at xi = 0.
FloatArray xi_0 = {0.0};
FloatMatrix dNdxi;
FEInterpolation *interp = this->giveInterpolation();
// interp->evaldNdxi( dNdxi, ip->giveNaturalCoordinates(), FEIElementGeometryWrapper(this) );
interp->evaldNdxi( dNdxi, xi_0, FEIElementGeometryWrapper(this) );
G.resize(2);
G.zero();
int numNodes = this->giveNumberOfNodes();
for ( int i = 1; i <= dNdxi.giveNumberOfRows(); i++ ) {
double X1_i = 0.5 * ( this->giveNode(i)->giveCoordinate(1) + this->giveNode(i + numNodes / 2)->giveCoordinate(1) ); // (mean) point on the fictious mid surface
double X2_i = 0.5 * ( this->giveNode(i)->giveCoordinate(2) + this->giveNode(i + numNodes / 2)->giveCoordinate(2) );
G.at(1) += dNdxi.at(i, 1) * X1_i;
G.at(2) += dNdxi.at(i, 1) * X2_i;
}
}