void dmtxm(double prod[3][3], /* Out: product of the two matrices */
double mat1[3][3], /* In: matrix 1 */
double mat2[3][3])
{ /* In: matrix 2 */
double trans[3][3];
dm_trans(trans, mat1);
prod[0][0] = trans[0][0] * mat2[0][0] + trans[0][1] * mat2[1][0] + trans[0][2] * mat2[2][0];
prod[0][1] = trans[0][0] * mat2[0][1] + trans[0][1] * mat2[1][1] + trans[0][2] * mat2[2][1];
prod[0][2] = trans[0][0] * mat2[0][2] + trans[0][1] * mat2[1][2] + trans[0][2] * mat2[2][2];
prod[1][0] = trans[1][0] * mat2[0][0] + trans[1][1] * mat2[1][0] + trans[1][2] * mat2[2][0];
prod[1][1] = trans[1][0] * mat2[0][1] + trans[1][1] * mat2[1][1] + trans[1][2] * mat2[2][1];
prod[1][2] = trans[1][0] * mat2[0][2] + trans[1][1] * mat2[1][2] + trans[1][2] * mat2[2][2];
prod[2][0] = trans[2][0] * mat2[0][0] + trans[2][1] * mat2[1][0] + trans[2][2] * mat2[2][0];
prod[2][1] = trans[2][0] * mat2[0][1] + trans[2][1] * mat2[1][1] + trans[2][2] * mat2[2][1];
prod[2][2] = trans[2][0] * mat2[0][2] + trans[2][1] * mat2[1][2] + trans[2][2] * mat2[2][2];
return;
}
void dmxmt(double prod[3][3], /* Out: Product of the two matrices */
double mat1[3][3], /* In: Matrix 1 */
double mat2[3][3])
{ /* In: Matrix 2 */
double trans[3][3];
dm_trans(trans, mat2);
prod[0][0] = mat1[0][0] * trans[0][0] + mat1[0][1] * trans[1][0] + mat1[0][2] * trans[2][0];
prod[0][1] = mat1[0][0] * trans[0][1] + mat1[0][1] * trans[1][1] + mat1[0][2] * trans[2][1];
prod[0][2] = mat1[0][0] * trans[0][2] + mat1[0][1] * trans[1][2] + mat1[0][2] * trans[2][2];
prod[1][0] = mat1[1][0] * trans[0][0] + mat1[1][1] * trans[1][0] + mat1[1][2] * trans[2][0];
prod[1][1] = mat1[1][0] * trans[0][1] + mat1[1][1] * trans[1][1] + mat1[1][2] * trans[2][1];
prod[1][2] = mat1[1][0] * trans[0][2] + mat1[1][1] * trans[1][2] + mat1[1][2] * trans[2][2];
prod[2][0] = mat1[2][0] * trans[0][0] + mat1[2][1] * trans[1][0] + mat1[2][2] * trans[2][0];
prod[2][1] = mat1[2][0] * trans[0][1] + mat1[2][1] * trans[1][1] + mat1[2][2] * trans[2][1];
prod[2][2] = mat1[2][0] * trans[0][2] + mat1[2][1] * trans[1][2] + mat1[2][2] * trans[2][2];
return;
}
