Method assemble

tools/Assembler/Assemblers/ElasticityTensorAssembler.cpp:9–48

using namespace PyMesh;

ZSparseMatrix ElasticityTensorAssembler::assemble(FESettingPtr setting) {
    typedef FESetting::FEMeshPtr FEMeshPtr;
    typedef FESetting::MaterialPtr MaterialPtr;

    typedef Eigen::Triplet<Float> T;
    std::vector<T> entries;

    FEMeshPtr mesh = setting->get_mesh();
    MaterialPtr material = setting->get_material();

    const size_t dim = mesh->getDim();
    const size_t num_elements = mesh->getNbrElements();
    MatrixI order = MatrixOrder::get_order(dim);
    size_t num_entries_per_element = dim * (dim+1) / 2;

    for (size_t i=0; i<num_elements; i++) {
        size_t base = i * num_entries_per_element;
        VectorF coord = mesh->getElementCenter(i);
        for (size_t j=0; j<dim; j++) {
            for (size_t k=j; k<dim; k++) {
                size_t tensor_row = order(j, k);
                for (size_t m=0; m<dim; m++) {
                    for (size_t n=0; n<dim; n++) {
                        size_t tensor_col = order(m, n);
                        Float entry = material->get_material_tensor(j,k,m,n,coord);
                        if (entry != 0.0) {
                            entries.push_back(T(base + tensor_row,
                                        base + tensor_col, entry));
                        }
                    }
                }
            }
        }
    }

    ZSparseMatrix C(num_elements * num_entries_per_element,
            num_elements* num_entries_per_element);
    C.setFromTriplets(entries.begin(), entries.end());
    return C;
}