From 425b462d361286822ee0ed7b5fe00881ba312ea3 Mon Sep 17 00:00:00 2001 From: vrouvrea Date: Fri, 5 Dec 2014 13:32:54 +0000 Subject: Moved into trunk git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/gudhi/trunk@341 636b058d-ea47-450e-bf9e-a15bfbe3eedb --- .../gudhi/Skeleton_blocker_simplifiable_complex.h | 525 +++++++++++++++++++++ 1 file changed, 525 insertions(+) create mode 100644 src/Skeleton_blocker/include/gudhi/Skeleton_blocker_simplifiable_complex.h (limited to 'src/Skeleton_blocker/include/gudhi/Skeleton_blocker_simplifiable_complex.h') diff --git a/src/Skeleton_blocker/include/gudhi/Skeleton_blocker_simplifiable_complex.h b/src/Skeleton_blocker/include/gudhi/Skeleton_blocker_simplifiable_complex.h new file mode 100644 index 00000000..4f9060ef --- /dev/null +++ b/src/Skeleton_blocker/include/gudhi/Skeleton_blocker_simplifiable_complex.h @@ -0,0 +1,525 @@ +/* + * Skeleton_blocker_simplifiable_complex.h + * + * Created on: Feb 4, 2014 + * Author: dsalinas + */ + +#ifndef GUDHI_SKELETON_BLOCKERS_SIMPLIFIABLE_COMPLEX_H_ +#define GUDHI_SKELETON_BLOCKERS_SIMPLIFIABLE_COMPLEX_H_ + +#include "gudhi/Skeleton_blocker/Skeleton_blocker_sub_complex.h" + +namespace Gudhi{ + +namespace skbl { + +/** + * \brief Class that allows simplification operation on a simplicial complex represented + * by a skeleton/blockers pair. + */ +template +class Skeleton_blocker_simplifiable_complex : public Skeleton_blocker_complex +{ + template friend class Skeleton_blocker_sub_complex; + +public: + + typedef Skeleton_blocker_complex SkeletonBlockerComplex; + + typedef typename SkeletonBlockerComplex::Graph_edge Graph_edge; + + typedef typename SkeletonBlockerComplex::boost_adjacency_iterator boost_adjacency_iterator; + typedef typename SkeletonBlockerComplex::Edge_handle Edge_handle; + typedef typename SkeletonBlockerComplex::boost_vertex_handle boost_vertex_handle; + typedef typename SkeletonBlockerComplex::Vertex_handle Vertex_handle; + typedef typename SkeletonBlockerComplex::Root_vertex_handle Root_vertex_handle; + typedef typename SkeletonBlockerComplex::Simplex_handle Simplex_handle; + typedef typename SkeletonBlockerComplex::Root_simplex_handle Root_simplex_handle; + typedef typename SkeletonBlockerComplex::Blocker_handle Blocker_handle; + + + typedef typename SkeletonBlockerComplex::Root_simplex_iterator Root_simplex_iterator; + typedef typename SkeletonBlockerComplex::Simplex_handle_iterator Simplex_handle_iterator; + typedef typename SkeletonBlockerComplex::BlockerMap BlockerMap; + typedef typename SkeletonBlockerComplex::BlockerPair BlockerPair; + typedef typename SkeletonBlockerComplex::BlockerMapIterator BlockerMapIterator; + typedef typename SkeletonBlockerComplex::BlockerMapConstIterator BlockerMapConstIterator; + + typedef typename SkeletonBlockerComplex::Visitor Visitor; + + + /** @name Constructors / Destructors / Initialization + */ + //@{ + Skeleton_blocker_simplifiable_complex(int num_vertices_ = 0,Visitor* visitor_=NULL): + Skeleton_blocker_complex(num_vertices_,visitor_){ } + + + /** + * @brief Constructor with a list of simplices + * @details The list of simplices must be the list + * of simplices of a simplicial complex, sorted with increasing dimension. + * todo take iterator instead + */ + Skeleton_blocker_simplifiable_complex(std::list& simplices,Visitor* visitor_=NULL): + Skeleton_blocker_complex(simplices,visitor_) + {} + + + + virtual ~Skeleton_blocker_simplifiable_complex(){ + } + + //@} + + /** + * Returns true iff the blocker 'sigma' is popable. + * To define popable, let us call 'L' the complex that + * consists in the current complex without the blocker 'sigma'. + * A blocker 'sigma' is then "popable" if the link of 'sigma' + * in L is reducible. + * + */ + virtual bool is_popable_blocker(Blocker_handle sigma) const{ + assert(this->contains_blocker(*sigma)); + Skeleton_blocker_link_complex link_blocker_sigma; + build_link_of_blocker(*this,*sigma,link_blocker_sigma); + + bool res = link_blocker_sigma.is_contractible()==CONTRACTIBLE; + return res; + } + + + + +private: + /** + * @returns the list of blockers of the simplex + * + * @todo a enlever et faire un iterateur sur tous les blockers a la place + */ + std::list get_blockers(){ + std::list res; + for (auto blocker : this->blocker_range()){ + res.push_back(blocker); + } + return res; + } + + + +public: + + /** + * Removes all the popable blockers of the complex and delete them. + * @returns the number of popable blockers deleted + */ + void remove_popable_blockers(){ + std::list vertex_to_check; + for(auto v : this->vertex_range()) + vertex_to_check.push_front(v); + + while(!vertex_to_check.empty()){ + Vertex_handle v = vertex_to_check.front(); + vertex_to_check.pop_front(); + + bool blocker_popable_found=true; + while (blocker_popable_found){ + blocker_popable_found = false; + for(auto block : this->blocker_range(v)){ + if (this->is_popable_blocker(block)) { + for(Vertex_handle nv : *block) + if(nv!=v) vertex_to_check.push_back(nv); + this->delete_blocker(block); + blocker_popable_found = true; + break; + } + } + } + } + } + + + /** + * Removes all the popable blockers of the complex passing through v and delete them. + */ + void remove_popable_blockers(Vertex_handle v){ + bool blocker_popable_found=true; + while (blocker_popable_found){ + blocker_popable_found = false; + for(auto block : this->blocker_range(v)){ + if (is_popable_blocker(block)) { + this->delete_blocker(block); + blocker_popable_found = true; + } + } + } + } + + + /** + * Remove the star of the vertex 'v' + */ + void remove_star(Vertex_handle v){ + // we remove the blockers that are not consistent anymore + + update_blockers_after_remove_star_of_vertex_or_edge(v); + + while (this->degree(v) > 0) + { + Vertex_handle w( * (adjacent_vertices(v.vertex, this->skeleton).first)); + this->remove_edge(v,w); + } + this->remove_vertex(v); + } + +private: + /** + * after removing the star of a simplex, blockers sigma that contains this simplex must be removed. + * Furthermore, all simplices tau of the form sigma \setminus simplex_to_be_removed must be added + * whenever the dimension of tau is at least 2. + */ + void update_blockers_after_remove_star_of_vertex_or_edge(const Simplex_handle& simplex_to_be_removed){ + std::list blockers_to_update; + if(simplex_to_be_removed.empty()) return; + + auto v0 = simplex_to_be_removed.first_vertex(); + for (auto blocker : this->blocker_range(v0)){ + if(blocker->contains(simplex_to_be_removed)) + blockers_to_update.push_back(blocker); + } + + for(auto blocker_to_update : blockers_to_update){ + Simplex_handle sub_blocker_to_be_added; + bool sub_blocker_need_to_be_added = + (blocker_to_update->dimension()-simplex_to_be_removed.dimension()) >= 2; + if(sub_blocker_need_to_be_added){ + sub_blocker_to_be_added = *blocker_to_update; + sub_blocker_to_be_added.difference(simplex_to_be_removed); + } + this->delete_blocker(blocker_to_update); + if(sub_blocker_need_to_be_added) + this->add_blocker(sub_blocker_to_be_added); + } + } + + + +public: + /** + * Remove the star of the edge connecting vertices a and b. + * @returns the number of blocker that have been removed + */ + void remove_star(Vertex_handle a, Vertex_handle b){ + update_blockers_after_remove_star_of_vertex_or_edge(Simplex_handle(a,b)); + // we remove the edge + this->remove_edge(a,b); + } + + + /** + * Remove the star of the edge 'e'. + */ + void remove_star(Edge_handle e){ + return remove_star(this->first_vertex(e),this->second_vertex(e)); + } + + /** + * Remove the star of the simplex 'sigma' which needs to belong to the complex + */ + void remove_star(const Simplex_handle& sigma){ + assert(this->contains(sigma)); + if (sigma.dimension()==0) + remove_star(sigma.first_vertex()); + else + if (sigma.dimension()==1) + remove_star(sigma.first_vertex(),sigma.last_vertex()); + else + update_blockers_after_remove_star_of_simplex(sigma); + } + +private: + void update_blockers_after_remove_star_of_simplex(const Simplex_handle& sigma){ + std::list blockers_to_remove; + for (auto blocker : this->blocker_range(sigma.first_vertex())){ + if(blocker->contains(sigma)) + blockers_to_remove.push_back(blocker); + } + for(auto blocker_to_update : blockers_to_remove) + this->delete_blocker(blocker_to_update); + this->add_blocker(sigma); + } + +public: + + enum simplifiable_status{ NOT_HOMOTOPY_EQ,MAYBE_HOMOTOPY_EQ,HOMOTOPY_EQ}; + simplifiable_status is_remove_star_homotopy_preserving(const Simplex_handle& simplex){ + return MAYBE_HOMOTOPY_EQ; + } + + + + enum contractible_status{ NOT_CONTRACTIBLE,MAYBE_CONTRACTIBLE,CONTRACTIBLE}; + /** + * @brief %Test if the complex is reducible using a strategy defined in the class + * (by default it tests if the complex is a cone) + * @details Note that NO could be returned if some invariant ensures that the complex + * is not a point (for instance if the euler characteristic is different from 1). + * This function will surely have to return MAYBE in some case because the + * associated problem is undecidable but it in practice, it can often + * be solved with the help of geometry. + */ + virtual contractible_status is_contractible() const{ + if (this->is_cone()) return CONTRACTIBLE; + else return MAYBE_CONTRACTIBLE; + // return this->is_cone(); + } + + + /** @Edge contraction operations + */ + //@{ + + + + /** + * @return If ignore_popable_blockers is true + * then the result is true iff the link condition at edge ab is satisfied + * or equivalently iff no blocker contains ab. + * If ignore_popable_blockers is false then the + * result is true iff all blocker containing ab are popable. + */ + bool link_condition(Vertex_handle a, Vertex_handle b,bool ignore_popable_blockers = false) const{ + for (auto blocker : this->const_blocker_range(a)) + if ( blocker->contains(b) ){ + // false if ignore_popable_blockers is false + // otherwise the blocker has to be popable + return ignore_popable_blockers && is_popable_blocker(blocker); + } + return true; + } + + /** + * @return If ignore_popable_blockers is true + * then the result is true iff the link condition at edge ab is satisfied + * or equivalently iff no blocker contains ab. + * If ignore_popable_blockers is false then the + * result is true iff all blocker containing ab are popable. + */ + bool link_condition(Edge_handle & e,bool ignore_popable_blockers = false) const{ + const Graph_edge& edge = (*this)[e]; + assert(this->get_address(edge.first())); + assert(this->get_address(edge.second())); + Vertex_handle a(*this->get_address(edge.first())); + Vertex_handle b(*this->get_address(edge.second())); + return link_condition(a,b,ignore_popable_blockers); + } + + +protected: + /** + * Compute simplices beta such that a.beta is an order 0 blocker + * that may be used to construct a new blocker after contracting ab. + * Suppose that the link condition Link(ab) = Link(a) inter Link(b) + * is satisfied. + */ + void tip_blockers(Vertex_handle a, Vertex_handle b, std::vector & buffer) const{ + for (auto const & blocker : this->const_blocker_range(a)) + { + Simplex_handle beta = (*blocker); + beta.remove_vertex(a); + buffer.push_back(beta); + } + + Simplex_handle n; + this->add_neighbours(b,n); + this->remove_neighbours(a,n); + n.remove_vertex(a); + + + for (Vertex_handle y : n) + { + Simplex_handle beta; + beta.add_vertex( y ); + buffer.push_back(beta); + } + } + + +private: + + /** + * @brief "Replace" the edge 'bx' by the edge 'ax'. + * Assume that the edge 'bx' was present whereas 'ax' was not. + * Precisely, it does not replace edges, but remove 'bx' and then add 'ax'. + * The visitor 'on_swaped_edge' is called just after edge 'ax' had been added + * and just before edge 'bx' had been removed. That way, it can + * eventually access to information of 'ax'. + */ + void swap_edge(Vertex_handle a,Vertex_handle b,Vertex_handle x){ + this->add_edge(a,x); + if (this->visitor) this->visitor->on_swaped_edge(a,b,x); + this->remove_edge(b,x); + } + + +private: + /** + * @brief removes all blockers passing through the edge 'ab' + */ + void delete_blockers_around_vertex(Vertex_handle v){ + std::list blockers_to_delete; + for (auto blocker : this->blocker_range(v)){ + blockers_to_delete.push_back(blocker); + } + while (!blockers_to_delete.empty()){ + this->remove_blocker(blockers_to_delete.back()); + blockers_to_delete.pop_back(); + } + + } + /** + * @brief removes all blockers passing through the edge 'ab' + */ + void delete_blockers_around_edge(Vertex_handle a, Vertex_handle b){ + std::list blocker_to_delete; + for (auto blocker : this->blocker_range(a)) + if (blocker->contains(b)) blocker_to_delete.push_back(blocker); + while (!blocker_to_delete.empty()) + { + this->delete_blocker(blocker_to_delete.back()); + blocker_to_delete.pop_back(); + } + } + +public: + + /** + * Contracts the edge. + * @remark If the link condition Link(ab) = Link(a) inter Link(b) is not satisfied, + * it removes first all blockers passing through 'ab' + */ + void contract_edge(Edge_handle edge){ + contract_edge(this->first_vertex(edge),this->second_vertex(edge)); + } + + + /** + * Contracts the edge connecting vertices a and b. + * @remark If the link condition Link(ab) = Link(a) inter Link(b) is not satisfied, + * it removes first all blockers passing through 'ab' + */ + void contract_edge(Vertex_handle a, Vertex_handle b){ + assert(this->contains_vertex(a)); + assert(this->contains_vertex(b)); + assert(this->contains_edge(a,b)); + + // if some blockers passes through 'ab', we remove them. + if (!link_condition(a,b)) + delete_blockers_around_edge(a,b); + + std::set blockers_to_add; + + get_blockers_to_be_added_after_contraction(a,b,blockers_to_add); + + delete_blockers_around_vertices(a,b); + + update_edges_after_contraction(a,b); + + this->remove_vertex(b); + + notify_changed_edges(a); + + for(auto block : blockers_to_add) + this->add_blocker(block); + + assert(this->contains_vertex(a)); + assert(!this->contains_vertex(b)); + } + + +private: + + void get_blockers_to_be_added_after_contraction(Vertex_handle a,Vertex_handle b,std::set& blockers_to_add){ + blockers_to_add.clear(); + + typedef Skeleton_blocker_link_complex > LinkComplexType; + + LinkComplexType link_a(*this,a); + LinkComplexType link_b(*this,b); + + std::vector vector_alpha, vector_beta; + + tip_blockers(a,b,vector_alpha); + tip_blockers(b,a,vector_beta); + + for (auto alpha = vector_alpha.begin(); alpha != vector_alpha.end(); ++alpha){ + for (auto beta = vector_beta.begin(); beta != vector_beta.end(); ++beta) + { + Simplex_handle sigma = *alpha; sigma.union_vertices(*beta); + Root_simplex_handle sigma_id = this->get_id(sigma); + if ( this->contains(sigma) && + proper_faces_in_union(sigma_id,link_a,link_b)) + { + // Blocker_handle blocker = new Simplex_handle(sigma); + sigma.add_vertex(a); + blockers_to_add.insert(sigma); + } + } + } + } + + + /** + * delete all blockers that passes through a or b + */ + void delete_blockers_around_vertices(Vertex_handle a,Vertex_handle b){ + std::vector blocker_to_delete; + for(auto bl : this->blocker_range(a)) + blocker_to_delete.push_back(bl); + for(auto bl : this->blocker_range(b)) + blocker_to_delete.push_back(bl); + while (!blocker_to_delete.empty()) + { + this->delete_blocker(blocker_to_delete.back()); + blocker_to_delete.pop_back(); + } + } + + + void update_edges_after_contraction(Vertex_handle a,Vertex_handle b){ + // We update the set of edges + this->remove_edge(a,b); + + // For all edges {b,x} incident to b, + // we remove {b,x} and add {a,x} if not already there. + while (this->degree(b)> 0) + { + Vertex_handle x(*(adjacent_vertices(b.vertex, this->skeleton).first)); + if(!this->contains_edge(a,x)) + // we 'replace' the edge 'bx' by the edge 'ax' + this->swap_edge(a,b,x); + else + this->remove_edge(b,x); + } + } + + void notify_changed_edges(Vertex_handle a){ + // We notify the visitor that all edges incident to 'a' had changed + boost_adjacency_iterator v, v_end; + + for (tie(v, v_end) = adjacent_vertices(a.vertex, this->skeleton); v != v_end; ++v) + if (this->visitor) this->visitor->on_changed_edge(a,Vertex_handle(*v)); + } + + //@} + + +}; + +} + +} // namespace GUDHI + +#endif /* GUDHI_SKELETON_BLOCKERS_SIMPLIFIABLE_COMPLEX_H_ */ -- cgit v1.2.3