void
StructuralInterfaceMaterial :: give2dStiffnessMatrix_Eng(FloatMatrix &answer, MatResponseMode mode, GaussPoint *gp, TimeStep *tStep)
{
FloatMatrix answer3D;
give3dStiffnessMatrix_Eng(answer3D, mode, gp, tStep);
IntArray mask = {1, 3};
answer.beSubMatrixOf(answer3D, mask, mask);
#if 0
//debug
printf("analytical tangent \n");
answer3D.printYourself();
FloatMatrix answerNum;
StructuralInterfaceMaterial :: giveStiffnessMatrix_dTdj_Num(answerNum, mode, gp, tStep);
printf("numerical tangent \n");
answerNum.printYourself();
FloatMatrix comp;
comp = answer3D;
comp.subtract(answerNum);
printf("difference in numerical tangent to mat method \n");
comp.printYourself();
#endif
}
void
StructuralInterfaceMaterial :: give1dStiffnessMatrix_Eng(FloatMatrix &answer, MatResponseMode mode, GaussPoint *gp, TimeStep *tStep)
{
FloatMatrix answer3D;
give3dStiffnessMatrix_Eng(answer3D, mode, gp, tStep);
answer.resize(1, 1);
answer.at(1, 1) = answer3D.at(3, 3);
}
