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author | ROUVREAU Vincent <vincent.rouvreau@inria.fr> | 2020-09-01 14:51:25 +0200 |
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committer | ROUVREAU Vincent <vincent.rouvreau@inria.fr> | 2020-09-01 14:51:25 +0200 |
commit | c2eb0484191f89fcbe40bc4ab04943eb808f12a9 (patch) | |
tree | 272289c27b583d4444e5e273ced5846561b5a9d1 /src/python/gudhi | |
parent | cea821f9ca34c270a5ccc047342c2c21ae79a6c0 (diff) |
expansion with blocker and how to modify filtration value
Diffstat (limited to 'src/python/gudhi')
-rw-r--r-- | src/python/gudhi/simplex_tree.pxd | 2 | ||||
-rw-r--r-- | src/python/gudhi/simplex_tree.pyx | 23 |
2 files changed, 13 insertions, 12 deletions
diff --git a/src/python/gudhi/simplex_tree.pxd b/src/python/gudhi/simplex_tree.pxd index 44533d7f..80c6ffca 100644 --- a/src/python/gudhi/simplex_tree.pxd +++ b/src/python/gudhi/simplex_tree.pxd @@ -66,7 +66,7 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi": vector[Simplex_tree_simplex_handle].const_iterator get_filtration_iterator_end() nogil Simplex_tree_skeleton_iterator get_skeleton_iterator_begin(int dimension) nogil Simplex_tree_skeleton_iterator get_skeleton_iterator_end(int dimension) nogil - # + # Expansion with blockers ctypedef bool (*blocker_func)(vector[int], void *user_data) void expansion_with_blockers_callback(int dimension, blocker_func user_func, void *user_data) diff --git a/src/python/gudhi/simplex_tree.pyx b/src/python/gudhi/simplex_tree.pyx index e297cfbd..debe92c0 100644 --- a/src/python/gudhi/simplex_tree.pyx +++ b/src/python/gudhi/simplex_tree.pyx @@ -413,21 +413,22 @@ cdef class SimplexTree: return self.get_ptr().compute_extended_persistence_subdiagrams(persistence_result, min_persistence) def expansion_with_blocker(self, max_dim, blocker_func): - """Expands the Simplex_tree containing only its one skeleton - until dimension max_dim. + """Expands the Simplex_tree containing only a graph. Simplices corresponding to cliques in the graph are added + incrementally, faces before cofaces, unless the simplex has dimension larger than `max_dim` or `blocker_func` + returns `True` for this simplex. - The expanded simplicial complex until dimension :math:`d` - attached to a graph :math:`G` is the maximal simplicial complex of - dimension at most :math:`d` admitting the graph :math:`G` as - :math:`1`-skeleton. - The filtration value assigned to a simplex is the maximal filtration - value of one of its edges. + The function identifies a candidate simplex whose faces are all already in the complex, inserts it with a + filtration value corresponding to the maximum of the filtration values of the faces, then calls `blocker_func` + with this new simplex (represented as a list of int). If `blocker_func` returns `True`, the simplex is removed, + otherwise it is kept. The algorithm then proceeds with the next candidate. - The Simplex_tree must contain no simplex of dimension bigger than - 1 when calling the method. + Note that you cannot update the filtration value of the simplex during the evaluation of `blocker_func`, as it + would segfault. - :param max_dim: The maximal dimension. + :param max_dim: Expansion maximal dimension value. :type max_dim: int + :param blocker_func: Blocker oracle. + :type blocker_func: Its concept is `Boolean blocker_func(list of int)` """ self.get_ptr().expansion_with_blockers_callback(max_dim, callback, <void*>blocker_func) |