inline UL& get_rev_diag( UL x )
{
if( x <size_max()/2 )
{
PUL ind = tri_ind(x , size_x() , size_y() );
return get_x_y( ind.first , size_y() - ind.second - 1 );
}
else
{
UL xm = size_max() - x -1;
PUL ind = tri_ind(xm , size_x() , size_y() );
return get_x_y( size_x() - ind.first - 1 , ind.second );
}
}
// make C8 element stiffness matrix
void CHak3DCont_8::makeKe()
{
int i,j,k,inc; //,err;
double sum, Jdet;
Coord3D gp;
Coord3D np[8];
if(Ke){delete [] Ke;}
Ke = new double [300]();
// read in node coordinates
getNcrd(np);
// get material property matrix
double *Em = Mat->getD();
double B[144]; // Strain displacement matrix (6 x 24)
double Bt[144]; // Auxillary matrix
// use 2 point Gauss rule (8 points total)
for(i=0;i<8;i++)
{
gp.x = gauss2 * c8_pos[i].x;
gp.y = gauss2 * c8_pos[i].y;
gp.z = gauss2 * c8_pos[i].z;
// compute isoparametric B matrix (6 x 24)
Jdet = C8_isoBMat(gp, np, B);
if(Jdet < 1.0E-12 || Jdet > 1.0E+15)
{
std::cout << "\nERROR in makeKe for C8 element, Jdet = " << Jdet;
}
// first multiply B^T * D
cblas_dgemm(CblasRowMajor, CblasTrans, CblasNoTrans, 24, 6, 6, 1.0, B, 24, Em, 6, 0.0, Bt, 6);
// complete multiplication (for upper triangle only)
for(j=0;j<24;j++) // rows
{
for(k=j;k<24;k++) // columns (upper triangle)
{
sum = 0.0;
for(inc=0;inc<6;inc++)
{
sum += Bt[index2(j,inc,6)]*B[index2(inc,k,24)];
}
Ke[tri_ind(24,j,k)] += sum*Jdet; //*weight;
}
}
}
}
