diff options
Diffstat (limited to 'src/python/gudhi')
-rw-r--r-- | src/python/gudhi/__init__.py.in | 4 | ||||
-rw-r--r-- | src/python/gudhi/simplex_tree.pyx | 15 |
2 files changed, 7 insertions, 12 deletions
diff --git a/src/python/gudhi/__init__.py.in b/src/python/gudhi/__init__.py.in index 3043201a..79e12fbc 100644 --- a/src/python/gudhi/__init__.py.in +++ b/src/python/gudhi/__init__.py.in @@ -23,10 +23,6 @@ __all__ = [@GUDHI_PYTHON_MODULES@ @GUDHI_PYTHON_MODULES_EXTRA@] __available_modules = '' __missing_modules = '' -# For unitary tests purpose -# could use "if 'collapse_edges' in gudhi.__all__" when collapse edges will have a python module -__GUDHI_USE_EIGEN3 = @GUDHI_USE_EIGEN3@ - # Try to import * from gudhi.__module_name for default modules. # Extra modules require an explicit import by the user (mostly because of # unusual dependencies, but also to avoid cluttering namespace gudhi and diff --git a/src/python/gudhi/simplex_tree.pyx b/src/python/gudhi/simplex_tree.pyx index a4914184..2c53a872 100644 --- a/src/python/gudhi/simplex_tree.pyx +++ b/src/python/gudhi/simplex_tree.pyx @@ -676,18 +676,17 @@ 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() |