* the vector is a set of pairs `(fe_index,dof_index)` that identifies
* the `fe_index` (an element of the `fes` argument to this function) of
* an element and the `dof_index` indicates the how-manyth degree of freedom
- * of that element on a vertex participates in this identity.
+ * of that element on a vertex participates in this identity. Now,
+ * every `fe_index` can appear only once in these sets (for each identity,
+ * only one degree of freedom of a finite element can be involved --
+ * otherwise we would have identities between different DoFs of the same
+ * element, which would make the element not unisolvent), and as a
+ * consequence the function does not actually return a set of
+ * `(fe_index,dof_index)` pairs for each identity, but instead a `std::map`
+ * from `fe_index` to `dof_index`, which is conceptually of course
+ * equivalent to a `std::set` of pairs, but in practice is easier to query.
*/
- std::vector<std::set<std::pair<unsigned int, unsigned int>>>
+ std::vector<std::map<unsigned int, unsigned int>>
hp_vertex_dof_identities(const std::set<unsigned int> &fes) const;
/**
* Same as hp_vertex_dof_indices(), except that the function treats degrees
* of freedom on lines.
*/
- std::vector<std::set<std::pair<unsigned int, unsigned int>>>
+ std::vector<std::map<unsigned int, unsigned int>>
hp_line_dof_identities(const std::set<unsigned int> &fes) const;
/**
* Same as hp_vertex_dof_indices(), except that the function treats degrees
* of freedom on quads.
*/
- std::vector<std::set<std::pair<unsigned int, unsigned int>>>
+ std::vector<std::map<unsigned int, unsigned int>>
hp_quad_dof_identities(const std::set<unsigned int> &fes,
const unsigned int face_no = 0) const;
// exists
if (identities.get() == nullptr)
{
- std::vector<std::set<std::pair<unsigned int, unsigned int>>>
+ std::vector<std::map<unsigned int, unsigned int>>
complete_identities;
switch (structdim)
// pairs (fe_index,dof_index). Because we put in exactly
// two fe indices, we know that each entry of the outer
// vector needs to contain a set of exactly two such
- // pairs. Check this.
+ // pairs. Check this. While there, also check that
+ // the two entries actually reference fe_index_1 and
+ // fe_index_2:
for (const auto &complete_identity : complete_identities)
- Assert(complete_identity.size() == 2, ExcInternalError());
+ {
+ Assert(complete_identity.size() == 2, ExcInternalError());
+ Assert(complete_identity.find(fe_index_1) !=
+ complete_identity.end(),
+ ExcInternalError());
+ Assert(complete_identity.find(fe_index_2) !=
+ complete_identity.end(),
+ ExcInternalError());
+ }
#endif
// Next reduce these sets of two pairs by removing the
// fe_index parts: We know which indices we have. But we
// have to make sure in which order we consider the
// pair, by considering whether the fe_index part we are
- // throwing away matched fe_index_1 or fe_index_2.
+ // throwing away matched fe_index_1 or fe_index_2. Fortunately,
+ // this is easy to do because we can ask the std::map for the
+ // dof_index that matches a given fe_index:
DoFIdentities reduced_identities;
for (const auto &complete_identity : complete_identities)
{
- std::pair<unsigned int, unsigned int> reduced_identity(
- complete_identity.begin()->second,
- (++complete_identity.begin())->second);
- if (complete_identity.begin()->first == fe_index_1)
- reduced_identities.emplace_back(reduced_identity);
- else if (complete_identity.begin()->first == fe_index_2)
- reduced_identities.emplace_back(reduced_identity.second,
- reduced_identity.first);
- else
- Assert(false, ExcInternalError());
+ const unsigned int dof_index_1 =
+ complete_identity.at(fe_index_1);
+ const unsigned int dof_index_2 =
+ complete_identity.at(fe_index_2);
+
+ reduced_identities.emplace_back(dof_index_1, dof_index_2);
}
#ifdef DEBUG
* Implement the action of the hp_*_dof_identities() functions
* in a generic way.
*/
- std::vector<std::set<std::pair<unsigned int, unsigned int>>>
+ std::vector<std::map<unsigned int, unsigned int>>
compute_hp_dof_identities(
const std::set<unsigned int> &fes,
const std::function<std::vector<std::pair<unsigned int, unsigned int>>(
const auto reduced_identities =
query_identities(fe_index_1, fe_index_2);
- std::vector<std::set<std::pair<unsigned int, unsigned int>>>
- complete_identities;
+ std::vector<std::map<unsigned int, unsigned int>> complete_identities;
for (const auto &reduced_identity : reduced_identities)
{
// Each identity returned by query_identities() is a pair of
// dof indices. Prefix each with its fe index and put the result
// into a vector
- std::set<std::pair<unsigned int, unsigned int>>
- complete_identity = {{fe_index_1, reduced_identity.first},
- {fe_index_2, reduced_identity.second}};
+ std::map<unsigned int, unsigned int> complete_identity = {
+ {fe_index_1, reduced_identity.first},
+ {fe_index_2, reduced_identity.second}};
complete_identities.emplace_back(std::move(complete_identity));
}
// run through because it modifies the graph and thus invalidates
// iterators. But because SG stores all of these edges, we can remove them
// all from G after collecting the edges in SG.)
- std::vector<std::set<Node>> identities;
+ std::vector<std::map<unsigned int, unsigned int>> identities;
while (identities_graph.size() > 0)
{
Graph sub_graph; // SG
// At this point we're sure that we have extracted a complete
// sub-graph ("clique"). The DoFs involved are all identical then, and
// we will store this identity so we can return it later.
- identities.emplace_back(std::move(sub_graph_nodes));
+ //
+ // The sub-graph is given as a set of Node objects, which is just
+ // a collection of (fe_index,dof_index) pairs. Because each
+ // fe_index can only appear once there, a better data structure
+ // is a std::map from fe_index to dof_index, which can conveniently
+ // be initialized from a range of iterators to pairs:
+ identities.emplace_back(sub_graph_nodes.begin(),
+ sub_graph_nodes.end());
+ Assert(identities.back().size() == sub_graph_nodes.size(),
+ ExcInternalError());
}
return identities;
template <int dim, int spacedim>
- std::vector<std::set<std::pair<unsigned int, unsigned int>>>
+ std::vector<std::map<unsigned int, unsigned int>>
FECollection<dim, spacedim>::hp_vertex_dof_identities(
const std::set<unsigned int> &fes) const
{
template <int dim, int spacedim>
- std::vector<std::set<std::pair<unsigned int, unsigned int>>>
+ std::vector<std::map<unsigned int, unsigned int>>
FECollection<dim, spacedim>::hp_line_dof_identities(
const std::set<unsigned int> &fes) const
{
template <int dim, int spacedim>
- std::vector<std::set<std::pair<unsigned int, unsigned int>>>
+ std::vector<std::map<unsigned int, unsigned int>>
FECollection<dim, spacedim>::hp_quad_dof_identities(
const std::set<unsigned int> &fes,
const unsigned int face_no) const
projects / dealii.git / commitdiff