void add_matrix_to_matrix(double scalar,
const fei::Matrix& src_matrix,
fei::Matrix& dest_matrix)
{
fei::SharedPtr<fei::VectorSpace> vspace = src_matrix.getMatrixGraph()->getRowSpace();
int numRows = vspace->getNumIndices_Owned();
std::vector<int> rows(numRows);
vspace->getIndices_Owned(numRows, &rows[0], numRows);
std::vector<int> indices;
std::vector<double> coefs;
for(size_t i=0; i<rows.size(); ++i) {
int rowlen = 0;
src_matrix.getRowLength(rows[i], rowlen);
if ((int)indices.size() < rowlen) {
indices.resize(rowlen);
coefs.resize(rowlen);
}
src_matrix.copyOutRow(rows[i], rowlen, &coefs[0], &indices[0]);
for(int j=0; j<rowlen; ++j) {
coefs[j] *= scalar;
}
double* coefPtr = &coefs[0];
dest_matrix.sumIn(1, &rows[i], rowlen, &indices[0], &coefPtr);
}
}
void assemble_elem_matrices_and_vectors(stk::mesh::BulkData& mesh,
stk::mesh::FieldBase& field,
stk::linsys::DofMapper& dof_mapper,
fei::Matrix& matrix,
fei::Vector& rhs)
{
stk::mesh::fem::FEMMetaData &fem = stk::mesh::fem::FEMMetaData::get(mesh);
const stk::mesh::EntityRank element_rank = fem.element_rank();
const std::vector<stk::mesh::Bucket*>& mesh_buckets = mesh.buckets(element_rank);
std::vector<stk::mesh::Bucket*> part_buckets;
stk::mesh::Selector select_owned(stk::mesh::MetaData::get(mesh).locally_owned_part());
stk::mesh::get_buckets(select_owned, mesh_buckets, part_buckets);
int field_id = dof_mapper.get_field_id(field);
stk::mesh::Entity& first_entity = *(part_buckets[0]->begin());
stk::mesh::PairIterRelation rel = first_entity.relations(stk::mesh::fem::FEMMetaData::NODE_RANK);
int num_nodes_per_elem = rel.second - rel.first;
fei::SharedPtr<fei::MatrixGraph> matgraph = matrix.getMatrixGraph();
int pattern_id = matgraph->definePattern(num_nodes_per_elem, stk::mesh::fem::FEMMetaData::NODE_RANK, field_id);
std::vector<int> node_ids(num_nodes_per_elem);
const int field_size = dof_mapper.get_fei_VectorSpace()->getFieldSize(field_id);
const int matsize = num_nodes_per_elem*field_size*num_nodes_per_elem*field_size;
const int vecsize = num_nodes_per_elem*field_size;
std::vector<double> elem_matrix_1d(matsize, 0);
std::vector<double*> elem_matrix_2d(vecsize);
std::vector<double> elem_vector(vecsize, 0);
for(size_t i=0; i<elem_matrix_2d.size(); ++i) {
elem_matrix_2d[i] = &elem_matrix_1d[i*vecsize];
}
//fill our dummy elem-matrix:
//This dummy matrix will be the same for every element. A real application
//would form a different elem-matrix for each element.
for(size_t i=0; i<elem_matrix_2d.size(); ++i) {
double* row = elem_matrix_2d[i];
if (i>=1) row[i-1] = -1;
row[i] = 2;
if (i<elem_matrix_2d.size()-1) row[i+1] = -1;
elem_vector[i] = 1;
}
std::vector<int> eqn_indices(vecsize);
for(size_t i=0; i<part_buckets.size(); ++i) {
stk::mesh::Bucket::iterator
b_iter = part_buckets[i]->begin(),
b_end = part_buckets[i]->end();
for(; b_iter != b_end; ++b_iter) {
stk::mesh::Entity& elem = *b_iter;
rel = elem.relations(stk::mesh::fem::FEMMetaData::NODE_RANK);
for(int j=0; rel.first != rel.second; ++rel.first, ++j) {
node_ids[j] = rel.first->entity()->identifier();
}
matgraph->getPatternIndices(pattern_id, &node_ids[0], eqn_indices);
matrix.sumIn(vecsize, &eqn_indices[0], vecsize, &eqn_indices[0],
&elem_matrix_2d[0]);
rhs.sumIn(vecsize, &eqn_indices[0], &elem_vector[0]);
}
}
}