Method getLaplacianMatrix

tools/Assembler/ref/Assembler3D.cpp:220–248

}

ZSparseMatrix Assembler3D::getLaplacianMatrix() {
    typedef Eigen::Triplet<double> T;
    std::vector<T> triplets;

    for (size_t i=0; i<m_mesh->getNbrElements(); ++i)
    {
        VectorI idx = m_mesh->getElement(i);
        assert(idx.size() == 4);

        Eigen::MatrixXd &dN = m_DN[i];

        // Small strain-displacement matrix
        // B = grad u for approximation.
        Eigen::MatrixXd B(3,4);
        B << dN(0,0),dN(1,0), dN(2,0),dN(3,0),
             dN(0,1),dN(1,1), dN(2,1),dN(3,1),
             dN(0,2),dN(1,2), dN(2,2),dN(3,2);

        Eigen::MatrixXd k_el = B.transpose() * B * m_mesh->getElementVolume(i);

        for (size_t j=0; j<4; ++j)
            for (size_t k=0; k<4; ++k)
                triplets.push_back(T(idx[j],idx[k], k_el(j,k)));
    }

    Eigen::SparseMatrix<double> L = Eigen::SparseMatrix<double>(m_mesh->getNbrNodes(),m_mesh->getNbrNodes());
    L.setFromTriplets(triplets.begin(), triplets.end());
    return ZSparseMatrix(L);
}

ZSparseMatrix Assembler3D::getDisplacementStrainMatrix() {
    typedef Eigen::Triplet<double> T;