diff options
Diffstat (limited to 'src/python/gudhi/simplex_tree.pyx')
| -rw-r--r-- | src/python/gudhi/simplex_tree.pyx | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/src/python/gudhi/simplex_tree.pyx b/src/python/gudhi/simplex_tree.pyx index a4914184..521a7763 100644 --- a/src/python/gudhi/simplex_tree.pyx +++ b/src/python/gudhi/simplex_tree.pyx @@ -474,8 +474,7 @@ cdef class SimplexTree: del self.pcohptr self.pcohptr = new Simplex_tree_persistence_interface(self.get_ptr(), False) self.pcohptr.compute_persistence(homology_coeff_field, -1.) - persistence_result = self.pcohptr.get_persistence() - return self.get_ptr().compute_extended_persistence_subdiagrams(persistence_result, min_persistence) + return self.pcohptr.compute_extended_persistence_subdiagrams(min_persistence) def expansion_with_blocker(self, max_dim, blocker_func): """Expands the Simplex_tree containing only a graph. Simplices corresponding to cliques in the graph are added @@ -676,18 +675,17 @@ cdef class SimplexTree: 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 + """Assuming the complex is a graph (simplices of higher dimension are ignored), this method implicitly + interprets it as the 1-skeleton of a flag complex, and replaces it with another (smaller) graph whose + expansion has the same persistent homology, using a technique known as edge collapses + (see :cite:`edgecollapsearxiv`). + + A natural application is to get a simplex tree of dimension 1 from :class:`~gudhi.RipsComplex`, + then collapse edges, perform :meth:`expansion()` and finally compute persistence (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 - - :note: collapse_edges method requires `Eigen <installation.html#eigen>`_ >= 3.1.0 and an exception is thrown - if this method is not available. """ # Backup old pointer cdef Simplex_tree_interface_full_featured* ptr = self.get_ptr() |