diff options
author | Vincent Rouvreau <10407034+VincentRouvreau@users.noreply.github.com> | 2020-08-03 11:41:56 +0200 |
---|---|---|
committer | GitHub <noreply@github.com> | 2020-08-03 11:41:56 +0200 |
commit | c4bec0cb470e98ee8169a53294b07a924fdb1d95 (patch) | |
tree | 5d1e5b639bc8c3d087025317dc0f473e6d600d84 /src | |
parent | 4857ebf6176217a68d605857207224dccc32da7b (diff) | |
parent | 010e8625ace3bbbfd09b7946237e8f3f04159452 (diff) |
Merge pull request #369 from VincentRouvreau/collapse_edges_stree_python
collapse edges for python simplex tree
Diffstat (limited to 'src')
-rw-r--r-- | src/python/doc/examples.rst | 33 | ||||
-rwxr-xr-x | src/python/example/rips_complex_edge_collapse_example.py | 62 | ||||
-rw-r--r-- | src/python/gudhi/simplex_tree.pxd | 1 | ||||
-rw-r--r-- | src/python/gudhi/simplex_tree.pyx | 66 | ||||
-rw-r--r-- | src/python/include/Simplex_tree_interface.h | 31 | ||||
-rwxr-xr-x | src/python/test/test_simplex_tree.py | 18 |
6 files changed, 173 insertions, 38 deletions
diff --git a/src/python/doc/examples.rst b/src/python/doc/examples.rst index a42227e3..76e5d4c7 100644 --- a/src/python/doc/examples.rst +++ b/src/python/doc/examples.rst @@ -7,27 +7,30 @@ Examples .. only:: builder_html - * :download:`rips_complex_from_points_example.py <../example/rips_complex_from_points_example.py>` + * :download:`alpha_complex_diagram_persistence_from_off_file_example.py <../example/alpha_complex_diagram_persistence_from_off_file_example.py>` * :download:`alpha_complex_from_points_example.py <../example/alpha_complex_from_points_example.py>` - * :download:`simplex_tree_example.py <../example/simplex_tree_example.py>` * :download:`alpha_rips_persistence_bottleneck_distance.py <../example/alpha_rips_persistence_bottleneck_distance.py>` - * :download:`tangential_complex_plain_homology_from_off_file_example.py <../example/tangential_complex_plain_homology_from_off_file_example.py>` - * :download:`alpha_complex_diagram_persistence_from_off_file_example.py <../example/alpha_complex_diagram_persistence_from_off_file_example.py>` - * :download:`periodic_cubical_complex_barcode_persistence_from_perseus_file_example.py <../example/periodic_cubical_complex_barcode_persistence_from_perseus_file_example.py>` * :download:`bottleneck_basic_example.py <../example/bottleneck_basic_example.py>` - * :download:`gudhi_graphical_tools_example.py <../example/gudhi_graphical_tools_example.py>` - * :download:`plot_simplex_tree_dim012.py <../example/plot_simplex_tree_dim012.py>` - * :download:`plot_rips_complex.py <../example/plot_rips_complex.py>` - * :download:`plot_alpha_complex.py <../example/plot_alpha_complex.py>` - * :download:`witness_complex_from_nearest_landmark_table.py <../example/witness_complex_from_nearest_landmark_table.py>` + * :download:`coordinate_graph_induced_complex.py <../example/coordinate_graph_induced_complex.py>` + * :download:`diagram_vectorizations_distances_kernels.py <../example/diagram_vectorizations_distances_kernels.py>` * :download:`euclidean_strong_witness_complex_diagram_persistence_from_off_file_example.py <../example/euclidean_strong_witness_complex_diagram_persistence_from_off_file_example.py>` * :download:`euclidean_witness_complex_diagram_persistence_from_off_file_example.py <../example/euclidean_witness_complex_diagram_persistence_from_off_file_example.py>` - * :download:`rips_complex_diagram_persistence_from_off_file_example.py <../example/rips_complex_diagram_persistence_from_off_file_example.py>` + * :download:`functional_graph_induced_complex.py <../example/functional_graph_induced_complex.py>` + * :download:`gudhi_graphical_tools_example.py <../example/gudhi_graphical_tools_example.py>` + * :download:`nerve_of_a_covering.py <../example/nerve_of_a_covering.py>` + * :download:`periodic_cubical_complex_barcode_persistence_from_perseus_file_example.py <../example/periodic_cubical_complex_barcode_persistence_from_perseus_file_example.py>` + * :download:`plot_alpha_complex.py <../example/plot_alpha_complex.py>` + * :download:`plot_rips_complex.py <../example/plot_rips_complex.py>` + * :download:`plot_simplex_tree_dim012.py <../example/plot_simplex_tree_dim012.py>` + * :download:`random_cubical_complex_persistence_example.py <../example/random_cubical_complex_persistence_example.py>` + * :download:`rips_complex_diagram_persistence_from_correlation_matrix_file_example.py <../example/rips_complex_diagram_persistence_from_correlation_matrix_file_example.py>` * :download:`rips_complex_diagram_persistence_from_distance_matrix_file_example.py <../example/rips_complex_diagram_persistence_from_distance_matrix_file_example.py>` + * :download:`rips_complex_diagram_persistence_from_off_file_example.py <../example/rips_complex_diagram_persistence_from_off_file_example.py>` + * :download:`rips_complex_edge_collapse_example.py <../example/rips_complex_edge_collapse_example.py>` + * :download:`rips_complex_from_points_example.py <../example/rips_complex_from_points_example.py>` * :download:`rips_persistence_diagram.py <../example/rips_persistence_diagram.py>` + * :download:`simplex_tree_example.py <../example/simplex_tree_example.py>` * :download:`sparse_rips_persistence_diagram.py <../example/sparse_rips_persistence_diagram.py>` - * :download:`random_cubical_complex_persistence_example.py <../example/random_cubical_complex_persistence_example.py>` - * :download:`coordinate_graph_induced_complex.py <../example/coordinate_graph_induced_complex.py>` - * :download:`functional_graph_induced_complex.py <../example/functional_graph_induced_complex.py>` + * :download:`tangential_complex_plain_homology_from_off_file_example.py <../example/tangential_complex_plain_homology_from_off_file_example.py>` * :download:`voronoi_graph_induced_complex.py <../example/voronoi_graph_induced_complex.py>` - * :download:`nerve_of_a_covering.py <../example/nerve_of_a_covering.py>` + * :download:`witness_complex_from_nearest_landmark_table.py <../example/witness_complex_from_nearest_landmark_table.py>` diff --git a/src/python/example/rips_complex_edge_collapse_example.py b/src/python/example/rips_complex_edge_collapse_example.py new file mode 100755 index 00000000..b26eb9fc --- /dev/null +++ b/src/python/example/rips_complex_edge_collapse_example.py @@ -0,0 +1,62 @@ +#!/usr/bin/env python + +import gudhi +import matplotlib.pyplot as plt +import time + +""" This file is part of the Gudhi Library - https://gudhi.inria.fr/ - which is released under MIT. + See file LICENSE or go to https://gudhi.inria.fr/licensing/ for full license details. + Author(s): Vincent Rouvreau + + Copyright (C) 2016 Inria + + Modification(s): + - YYYY/MM Author: Description of the modification +""" + +__author__ = "Vincent Rouvreau" +__copyright__ = "Copyright (C) 2020 Inria" +__license__ = "MIT" + + +print("#####################################################################") +print("RipsComplex (only the one-skeleton) creation from tore3D_300.off file") + +off_file = gudhi.__root_source_dir__ + '/data/points/tore3D_300.off' +point_cloud = gudhi.read_points_from_off_file(off_file = off_file) +rips_complex = gudhi.RipsComplex(points=point_cloud, max_edge_length=12.0) +simplex_tree = rips_complex.create_simplex_tree(max_dimension=1) +print('1. Rips complex is of dimension ', simplex_tree.dimension(), ' - ', + simplex_tree.num_simplices(), ' simplices - ', + simplex_tree.num_vertices(), ' vertices.') + +# Expansion of this one-skeleton would require a lot of memory. Let's collapse it +start = time.process_time() +simplex_tree.collapse_edges() +print('2. Rips complex is of dimension ', simplex_tree.dimension(), ' - ', + simplex_tree.num_simplices(), ' simplices - ', + simplex_tree.num_vertices(), ' vertices.') +simplex_tree.expansion(3) +diag = simplex_tree.persistence() +print("Collapse, expansion and persistence computation took ", time.process_time() - start, " sec.") + +# Use subplots to display diagram and density side by side +fig, axes = plt.subplots(nrows=1, ncols=2, figsize=(12, 5)) +gudhi.plot_persistence_diagram(diag, axes=axes[0]) +axes[0].set_title("Persistence after 1 collapse") + +# Collapse can be performed several times. Let's collapse it 3 times +start = time.process_time() +simplex_tree.collapse_edges(nb_iterations = 3) +print('3. Rips complex is of dimension ', simplex_tree.dimension(), ' - ', + simplex_tree.num_simplices(), ' simplices - ', + simplex_tree.num_vertices(), ' vertices.') +simplex_tree.expansion(3) +diag = simplex_tree.persistence() +print("Collapse, expansion and persistence computation took ", time.process_time() - start, " sec.") + +gudhi.plot_persistence_diagram(diag, axes=axes[1]) +axes[1].set_title("Persistence after 3 more collapses") + +# Plot the 2 persistence diagrams side to side to check the persistence is the same +plt.show()
\ No newline at end of file diff --git a/src/python/gudhi/simplex_tree.pxd b/src/python/gudhi/simplex_tree.pxd index e748ac40..75e94e0b 100644 --- a/src/python/gudhi/simplex_tree.pxd +++ b/src/python/gudhi/simplex_tree.pxd @@ -57,6 +57,7 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi": bool make_filtration_non_decreasing() nogil void compute_extended_filtration() nogil vector[vector[pair[int, pair[double, double]]]] compute_extended_persistence_subdiagrams(vector[pair[int, pair[double, double]]] dgm, double min_persistence) nogil + Simplex_tree_interface_full_featured* collapse_edges(int nb_collapse_iteration) nogil # Iterators over Simplex tree pair[vector[int], double] get_simplex_and_filtration(Simplex_tree_simplex_handle f_simplex) nogil Simplex_tree_simplices_iterator get_simplices_iterator_begin() nogil diff --git a/src/python/gudhi/simplex_tree.pyx b/src/python/gudhi/simplex_tree.pyx index 20e66d9f..dfb1d985 100644 --- a/src/python/gudhi/simplex_tree.pyx +++ b/src/python/gudhi/simplex_tree.pyx @@ -69,7 +69,7 @@ cdef class SimplexTree: this simplicial complex, or +infinity if it is not in the complex. :param simplex: The N-simplex, represented by a list of vertex. - :type simplex: list of int. + :type simplex: list of int :returns: The simplicial complex filtration value. :rtype: float """ @@ -80,7 +80,7 @@ cdef class SimplexTree: given N-simplex. :param simplex: The N-simplex, represented by a list of vertex. - :type simplex: list of int. + :type simplex: list of int :param filtration: The new filtration value. :type filtration: float @@ -153,7 +153,7 @@ cdef class SimplexTree: """This function sets the dimension of the simplicial complex. :param dimension: The new dimension value. - :type dimension: int. + :type dimension: int .. note:: @@ -172,7 +172,7 @@ cdef class SimplexTree: complex or not. :param simplex: The N-simplex to find, represented by a list of vertex. - :type simplex: list of int. + :type simplex: list of int :returns: true if the simplex was found, false otherwise. :rtype: bool """ @@ -186,9 +186,9 @@ cdef class SimplexTree: :param simplex: The N-simplex to insert, represented by a list of vertex. - :type simplex: list of int. + :type simplex: list of int :param filtration: The filtration value of the simplex. - :type filtration: float. + :type filtration: float :returns: true if the simplex was not yet in the complex, false otherwise (whatever its original filtration value). :rtype: bool @@ -228,7 +228,7 @@ cdef class SimplexTree: """This function returns a generator with the (simplices of the) skeleton of a maximum given dimension. :param dimension: The skeleton dimension value. - :type dimension: int. + :type dimension: int :returns: The (simplices of the) skeleton of a maximum dimension. :rtype: generator with tuples(simplex, filtration) """ @@ -243,7 +243,7 @@ cdef class SimplexTree: """This function returns the star of a given N-simplex. :param simplex: The N-simplex, represented by a list of vertex. - :type simplex: list of int. + :type simplex: list of int :returns: The (simplices of the) star of a simplex. :rtype: list of tuples(simplex, filtration) """ @@ -265,10 +265,10 @@ cdef class SimplexTree: given codimension. :param simplex: The N-simplex, represented by a list of vertex. - :type simplex: list of int. + :type simplex: list of int :param codimension: The codimension. If codimension = 0, all cofaces are returned (equivalent of get_star function) - :type codimension: int. + :type codimension: int :returns: The (simplices of the) cofaces of a simplex :rtype: list of tuples(simplex, filtration) """ @@ -290,7 +290,7 @@ cdef class SimplexTree: complex. :param simplex: The N-simplex, represented by a list of vertex. - :type simplex: list of int. + :type simplex: list of int .. note:: @@ -308,7 +308,7 @@ cdef class SimplexTree: """Prune above filtration value given as parameter. :param filtration: Maximum threshold value. - :type filtration: float. + :type filtration: float :returns: The filtration modification information. :rtype: bool @@ -342,7 +342,7 @@ cdef class SimplexTree: 1 when calling the method. :param max_dim: The maximal dimension. - :type max_dim: int. + :type max_dim: int """ cdef int maxdim = max_dim with nogil: @@ -383,12 +383,12 @@ cdef class SimplexTree: :param homology_coeff_field: The homology coefficient field. Must be a prime number. Default value is 11. - :type homology_coeff_field: int. + :type homology_coeff_field: int :param min_persistence: The minimum persistence value (i.e., the absolute value of the difference between the persistence diagram point coordinates) to take into account (strictly greater than min_persistence). Default value is 0.0. Sets min_persistence to -1.0 to see all values. - :type min_persistence: float. + :type min_persistence: float :returns: A list of four persistence diagrams in the format described in :func:`persistence`. The first one is Ordinary, the second one is Relative, the third one is Extended+ and the fourth one is Extended-. See https://link.springer.com/article/10.1007/s10208-008-9027-z and/or section 2.2 in https://link.springer.com/article/10.1007/s10208-017-9370-z for a description of these subtypes. .. note:: @@ -415,12 +415,12 @@ cdef class SimplexTree: :param homology_coeff_field: The homology coefficient field. Must be a prime number. Default value is 11. - :type homology_coeff_field: int. + :type homology_coeff_field: int :param min_persistence: The minimum persistence value to take into account (strictly greater than min_persistence). Default value is 0.0. Set min_persistence to -1.0 to see all values. - :type min_persistence: float. + :type min_persistence: float :param persistence_dim_max: If true, the persistent homology for the maximal dimension in the complex is computed. If false, it is ignored. Default is false. @@ -438,12 +438,12 @@ cdef class SimplexTree: :param homology_coeff_field: The homology coefficient field. Must be a prime number. Default value is 11. - :type homology_coeff_field: int. + :type homology_coeff_field: int :param min_persistence: The minimum persistence value to take into account (strictly greater than min_persistence). Default value is 0.0. Sets min_persistence to -1.0 to see all values. - :type min_persistence: float. + :type min_persistence: float :param persistence_dim_max: If true, the persistent homology for the maximal dimension in the complex is computed. If false, it is ignored. Default is false. @@ -478,10 +478,10 @@ cdef class SimplexTree: :param from_value: The persistence birth limit to be added in the numbers (persistent birth <= from_value). - :type from_value: float. + :type from_value: float :param to_value: The persistence death limit to be added in the numbers (persistent death > to_value). - :type to_value: float. + :type to_value: float :returns: The persistent Betti numbers ([B0, B1, ..., Bn]). :rtype: list of int @@ -498,7 +498,7 @@ cdef class SimplexTree: complex in a specific dimension. :param dimension: The specific dimension. - :type dimension: int. + :type dimension: int :returns: The persistence intervals. :rtype: numpy array of dimension 2 @@ -527,7 +527,7 @@ cdef class SimplexTree: complex in a user given file name. :param persistence_file: Name of the file. - :type persistence_file: string. + :type persistence_file: string :note: intervals_in_dim function requires :func:`compute_persistence` @@ -581,3 +581,23 @@ cdef class SimplexTree: infinite0 = np_array(next(l)) infinites = [np_array(d).reshape(-1,2) for d in l] return (normal0, normals, infinite0, infinites) + + def collapse_edges(self, nb_iterations = 1): + """Assuming the simplex tree is a 1-skeleton graph, this method collapse edges (simplices of higher dimension + are ignored) and resets the simplex tree from the remaining edges. + A good candidate is to build a simplex tree on top of a :class:`~gudhi.RipsComplex` of dimension 1 before + collapsing edges + (cf. :download:`rips_complex_edge_collapse_example.py <../example/rips_complex_edge_collapse_example.py>`). + For implementation details, please refer to :cite:`edgecollapsesocg2020`. + + :param nb_iterations: The number of edge collapse iterations to perform. Default is 1. + :type nb_iterations: int + """ + # Backup old pointer + cdef Simplex_tree_interface_full_featured* ptr = self.get_ptr() + cdef int nb_iter = nb_iterations + with nogil: + # New pointer is a new collapsed simplex tree + self.thisptr = <intptr_t>(ptr.collapse_edges(nb_iter)) + # Delete old pointer + del ptr diff --git a/src/python/include/Simplex_tree_interface.h b/src/python/include/Simplex_tree_interface.h index 56d7c41d..e288a8cf 100644 --- a/src/python/include/Simplex_tree_interface.h +++ b/src/python/include/Simplex_tree_interface.h @@ -15,10 +15,13 @@ #include <gudhi/distance_functions.h> #include <gudhi/Simplex_tree.h> #include <gudhi/Points_off_io.h> +#include <gudhi/Flag_complex_edge_collapser.h> #include <iostream> #include <vector> #include <utility> // std::pair +#include <tuple> +#include <iterator> // for std::distance namespace Gudhi { @@ -157,6 +160,34 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> { return new_dgm; } + Simplex_tree_interface* collapse_edges(int nb_collapse_iteration) { + using Filtered_edge = std::tuple<Vertex_handle, Vertex_handle, Filtration_value>; + std::vector<Filtered_edge> edges; + for (Simplex_handle sh : Base::skeleton_simplex_range(1)) { + if (Base::dimension(sh) == 1) { + typename Base::Simplex_vertex_range rg = Base::simplex_vertex_range(sh); + auto vit = rg.begin(); + Vertex_handle v = *vit; + Vertex_handle w = *++vit; + edges.emplace_back(v, w, Base::filtration(sh)); + } + } + + for (int iteration = 0; iteration < nb_collapse_iteration; iteration++) { + edges = Gudhi::collapse::flag_complex_collapse_edges(edges); + } + Simplex_tree_interface* collapsed_stree_ptr = new Simplex_tree_interface(); + // Copy the original 0-skeleton + for (Simplex_handle sh : Base::skeleton_simplex_range(0)) { + collapsed_stree_ptr->insert({*(Base::simplex_vertex_range(sh).begin())}, Base::filtration(sh)); + } + // Insert remaining edges + for (auto remaining_edge : edges) { + collapsed_stree_ptr->insert({std::get<0>(remaining_edge), std::get<1>(remaining_edge)}, std::get<2>(remaining_edge)); + } + return collapsed_stree_ptr; + } + // Iterator over the simplex tree Complex_simplex_iterator get_simplices_iterator_begin() { // this specific case works because the range is just a pair of iterators - won't work if range was a vector diff --git a/src/python/test/test_simplex_tree.py b/src/python/test/test_simplex_tree.py index 2137d822..83be0602 100755 --- a/src/python/test/test_simplex_tree.py +++ b/src/python/test/test_simplex_tree.py @@ -340,3 +340,21 @@ def test_simplices_iterator(): assert st.find(simplex[0]) == True print("filtration is: ", simplex[1]) assert st.filtration(simplex[0]) == simplex[1] + +def test_collapse_edges(): + st = SimplexTree() + + assert st.insert([0, 1], filtration=1.0) == True + assert st.insert([1, 2], filtration=1.0) == True + assert st.insert([2, 3], filtration=1.0) == True + assert st.insert([0, 3], filtration=1.0) == True + assert st.insert([0, 2], filtration=2.0) == True + assert st.insert([1, 3], filtration=2.0) == True + + assert st.num_simplices() == 10 + + st.collapse_edges() + assert st.num_simplices() == 9 + assert st.find([1, 3]) == False + for simplex in st.get_skeleton(0): + assert simplex[1] == 1. |