diff options
author | Vincent Rouvreau <vincent.rouvreau@inria.fr> | 2022-04-05 10:30:57 +0200 |
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committer | Vincent Rouvreau <vincent.rouvreau@inria.fr> | 2022-04-05 10:30:57 +0200 |
commit | 0d25c9db02cdc20c4b7ca1f48780eb7129ee8b82 (patch) | |
tree | 7fc33cf0a9bc8a5d5c15db714500d4440d32f2e2 /src | |
parent | b066b4376abf66ddc76e61a6a815a409b05fe59b (diff) |
Boundary and its opposite vertex iterator for the simplex tree
Diffstat (limited to 'src')
4 files changed, 160 insertions, 1 deletions
diff --git a/src/Simplex_tree/include/gudhi/Simplex_tree.h b/src/Simplex_tree/include/gudhi/Simplex_tree.h index d48f6616..63a7f190 100644 --- a/src/Simplex_tree/include/gudhi/Simplex_tree.h +++ b/src/Simplex_tree/include/gudhi/Simplex_tree.h @@ -187,6 +187,12 @@ class Simplex_tree { typedef Simplex_tree_boundary_simplex_iterator<Simplex_tree> Boundary_simplex_iterator; /** \brief Range over the simplices of the boundary of a simplex. */ typedef boost::iterator_range<Boundary_simplex_iterator> Boundary_simplex_range; + /** \brief Iterator over the simplices of the boundary and its opposite vertex of a simplex. + * + * 'value_type' is std::pair<Simplex_handle, Vertex_handle>. */ + typedef Simplex_tree_boundary_opposite_vertex_simplex_iterator<Simplex_tree> Boundary_opposite_vertex_simplex_iterator; + /** \brief Range over the simplices of the boundary and its opposite vertex of a simplex. */ + typedef boost::iterator_range<Boundary_opposite_vertex_simplex_iterator> Boundary_opposite_vertex_simplex_range; /** \brief Iterator over the simplices of the simplicial complex. * * 'value_type' is Simplex_handle. */ @@ -296,6 +302,23 @@ class Simplex_tree { Boundary_simplex_iterator(this)); } + /** \brief Returns a range over the simplices of the boundary and its opposite vertex of a simplex. + * + * The boundary and its opposite vertex of a simplex is the set of codimension \f$1\f$ subsimplices of the simplex. + * If the simplex is \f$[v_0, \cdots ,v_d]\f$, with canonical orientation induced by \f$ v_0 < \cdots < v_d \f$, the + * iterator enumerates the simplices of the boundary in the order: + * \f$[v_0,\cdots,\widehat{v_i},\cdots,v_d]\f$ for \f$i\f$ from \f$0\f$ to \f$d\f$, where \f$\widehat{v_i}\f$ means + * that the vertex \f$v_i\f$ is omitted from boundary, but returned as the second element of the pair, known as the + * the opposite vertex of the boundary. + * + * @param[in] sh Simplex for which the boundary and its opposite vertex is computed. + * @return Iterator on a pair of SimplexHandle (a boundary) and a VertexHandle (its opposite vertex). */ + template<class SimplexHandle> + Boundary_opposite_vertex_simplex_range boundary_opposite_vertex_simplex_range(SimplexHandle sh) { + return Boundary_opposite_vertex_simplex_range(Boundary_opposite_vertex_simplex_iterator(this, sh), + Boundary_opposite_vertex_simplex_iterator(this)); + } + /** @} */ // end range and iterator methods /** \name Constructor/Destructor * @{ */ diff --git a/src/Simplex_tree/include/gudhi/Simplex_tree/Simplex_tree_iterators.h b/src/Simplex_tree/include/gudhi/Simplex_tree/Simplex_tree_iterators.h index e5522cc7..841b4d49 100644 --- a/src/Simplex_tree/include/gudhi/Simplex_tree/Simplex_tree_iterators.h +++ b/src/Simplex_tree/include/gudhi/Simplex_tree/Simplex_tree_iterators.h @@ -5,6 +5,7 @@ * Copyright (C) 2014 Inria * * Modification(s): + * - 2022/04 Vincent Rouvreau: Add Simplex_tree_boundary_opposite_vertex_simplex_iterator for alpha and cech purpose * - YYYY/MM Author: Description of the modification */ @@ -17,6 +18,7 @@ #include <boost/container/static_vector.hpp> #include <vector> +#include <utility> // for std::pair namespace Gudhi { @@ -123,7 +125,7 @@ class Simplex_tree_boundary_simplex_iterator : public boost::iterator_facade< private: friend class boost::iterator_core_access; -// valid when iterating along the SAME boundary. + // valid when iterating along the SAME boundary. bool equal(Simplex_tree_boundary_simplex_iterator const& other) const { return sh_ == other.sh_; } @@ -178,6 +180,104 @@ class Simplex_tree_boundary_simplex_iterator : public boost::iterator_facade< Simplex_handle sh_; // current Simplex_handle in the boundary SimplexTree * st_; // simplex containing the simplicial complex }; + +/* \brief Iterator over the simplices of the boundary and opposite vertex of a simplex. + * + * Forward iterator, value_type is std::pair<SimplexTree::Simplex_handle, SimplexTree::Vertex_handle>.*/ +template<class SimplexTree> +class Simplex_tree_boundary_opposite_vertex_simplex_iterator : public boost::iterator_facade< + Simplex_tree_boundary_opposite_vertex_simplex_iterator<SimplexTree>, + std::pair<typename SimplexTree::Simplex_handle, typename SimplexTree::Vertex_handle> const, boost::forward_traversal_tag> { + public: + using Simplex_handle = typename SimplexTree::Simplex_handle; + using Vertex_handle = typename SimplexTree::Vertex_handle; + using Siblings = typename SimplexTree::Siblings; + + // For cython purpose only. The object it initializes should be overwritten ASAP and never used before it is + // overwritten. + Simplex_tree_boundary_opposite_vertex_simplex_iterator() + : sib_(nullptr), + st_(nullptr) { + } + + // any end() iterator + explicit Simplex_tree_boundary_opposite_vertex_simplex_iterator(SimplexTree * st) + : last_(st->null_vertex()), + next_(st->null_vertex()), + sib_(nullptr), + baov_(st->null_simplex(), st->null_vertex()), + st_(st) { + } + + template<class SimplexHandle> + Simplex_tree_boundary_opposite_vertex_simplex_iterator(SimplexTree * st, SimplexHandle sh) + : last_(sh->first), + next_(st->null_vertex()), + sib_(nullptr), + baov_(st->null_simplex(), sh->first), + st_(st) { + // Only check once at the beginning instead of for every increment, as this is expensive. + if (SimplexTree::Options::contiguous_vertices) + GUDHI_CHECK(st_->contiguous_vertices(), "The set of vertices is not { 0, ..., n } without holes"); + Siblings * sib = st->self_siblings(sh); + next_ = sib->parent(); + sib_ = sib->oncles(); + if (sib_ != nullptr) { + if (SimplexTree::Options::contiguous_vertices && sib_->oncles() == nullptr) + // Only relevant for edges + baov_.first = sib_->members_.begin()+next_; + else + baov_.first = sib_->find(next_); + } + } + + private: + friend class boost::iterator_core_access; + + // valid when iterating along the SAME boundary. + bool equal(Simplex_tree_boundary_opposite_vertex_simplex_iterator const& other) const { + return (baov_.first == other.baov_.first); + } + + std::pair<Simplex_handle, Vertex_handle> const& dereference() const { + return baov_; + } + + void increment() { + if (sib_ == nullptr) { + baov_.first = st_->null_simplex(); + return; // ------>> + } + Siblings * for_sib = sib_; + Siblings * new_sib = sib_->oncles(); + auto rit = suffix_.rbegin(); + for (; rit != suffix_.rend(); ++rit) { + baov_.first = for_sib->find(*rit); + for_sib = baov_.first->second.children(); + } + baov_.first = for_sib->find(last_); // baov_.first points to the right simplex now + suffix_.push_back(next_); + next_ = sib_->parent(); + sib_ = new_sib; + if (suffix_.empty()) + baov_.second = last_; + else + baov_.second = suffix_.back(); + } + + // Most of the storage should be moved to the range, iterators should be light. + Vertex_handle last_; // last vertex of the simplex + Vertex_handle next_; // next vertex to push in suffix_ + // 40 seems a conservative bound on the dimension of a Simplex_tree for now, + // as it would not fit on the biggest hard-drive. + boost::container::static_vector<Vertex_handle, 40> suffix_; + // static_vector still has some overhead compared to a trivial hand-made + // version using std::aligned_storage, or compared to making suffix_ static. + Siblings * sib_; // where the next search will start from + std::pair<Simplex_handle, Vertex_handle> baov_; // a pair containing the current Simplex_handle in the boundary and its opposite vertex + SimplexTree * st_; // simplex containing the simplicial complex +}; + /*---------------------------------------------------------------------------*/ /* \brief Iterator over the simplices of a simplicial complex. * diff --git a/src/Simplex_tree/include/gudhi/Simplex_tree/Simplex_tree_siblings.h b/src/Simplex_tree/include/gudhi/Simplex_tree/Simplex_tree_siblings.h index b53bad29..ae25d290 100644 --- a/src/Simplex_tree/include/gudhi/Simplex_tree/Simplex_tree_siblings.h +++ b/src/Simplex_tree/include/gudhi/Simplex_tree/Simplex_tree_siblings.h @@ -36,6 +36,7 @@ class Simplex_tree_siblings { template<class T> friend class Simplex_tree_boundary_simplex_iterator; template<class T> friend class Simplex_tree_complex_simplex_iterator; template<class T> friend class Simplex_tree_skeleton_simplex_iterator; + template<class T> friend class Simplex_tree_boundary_opposite_vertex_simplex_iterator; typedef typename SimplexTree::Vertex_handle Vertex_handle; typedef typename SimplexTree::Filtration_value Filtration_value; diff --git a/src/Simplex_tree/test/simplex_tree_unit_test.cpp b/src/Simplex_tree/test/simplex_tree_unit_test.cpp index bdd41d34..2c8a376c 100644 --- a/src/Simplex_tree/test/simplex_tree_unit_test.cpp +++ b/src/Simplex_tree/test/simplex_tree_unit_test.cpp @@ -991,3 +991,38 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(simplex_tree_reset_filtration, typeST, list_of_tes } +BOOST_AUTO_TEST_CASE_TEMPLATE(simplex_tree_boundaries_and_opposite_vertex_iterator, typeST, list_of_tested_variants) { + std::clog << "********************************************************************" << std::endl; + std::clog << "TEST OF BOUNDARIES AND OPPOSITE VERTEX ITERATORS" << std::endl; + typeST st; + + st.insert_simplex_and_subfaces({2, 1, 0}, 3.); + st.insert_simplex_and_subfaces({3, 0}, 2.); + st.insert_simplex_and_subfaces({3, 4, 5}, 3.); + st.insert_simplex_and_subfaces({0, 1, 6, 7}, 4.); + + /* Inserted simplex: */ + /* 1 6 */ + /* o---o */ + /* /X\7/ */ + /* o---o---o---o */ + /* 2 0 3\X/4 */ + /* o */ + /* 5 */ + using Simplex = std::vector<typename typeST::Vertex_handle>; + // simplices must be kept sorted by vertex number for std::vector to use operator== - cf. last BOOST_CHECK + std::vector<Simplex> simplices = {{0, 1, 2}, {0, 3}, {0, 1, 6, 7}, {3,4,5}, {3,5}}; + for (auto simplex : simplices) { + for(auto boundary_and_opposite_vertex : st.boundary_opposite_vertex_simplex_range(st.find(simplex))) { + Simplex output; + for (auto vertex : st.simplex_vertex_range(boundary_and_opposite_vertex.first)) { + std::clog << vertex << " "; + output.emplace_back(vertex); + } + std::clog << " - opposite vertex = " << boundary_and_opposite_vertex.second << std::endl; + output.emplace_back(boundary_and_opposite_vertex.second); + std::sort(output.begin(), output.end()); + BOOST_CHECK(simplex == output); + } + } +} |