Merge branch 'master' of https://github.com/GUDHI/gudhi-devel into diff

2 files changed, 27 insertions, 0 deletions

diff --git a/src/python/gudhi/simplex_tree.pxd b/src/python/gudhi/simplex_tree.pxd
index 5c98fb4a..4f229663 100644
--- a/src/python/gudhi/simplex_tree.pxd
+++ b/src/python/gudhi/simplex_tree.pxd
@@ -76,6 +76,9 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi":
         Simplex_tree_skeleton_iterator get_skeleton_iterator_begin(int dimension) nogil
         Simplex_tree_skeleton_iterator get_skeleton_iterator_end(int dimension) nogil
         pair[Simplex_tree_boundary_iterator, Simplex_tree_boundary_iterator] get_boundary_iterators(vector[int] simplex) nogil except +
+        # Expansion with blockers
+        ctypedef bool (*blocker_func_t)(vector[int], void *user_data)
+        void expansion_with_blockers_callback(int dimension, blocker_func_t user_func, void *user_data)
 
 cdef extern from "Persistent_cohomology_interface.h" namespace "Gudhi":
     cdef cppclass Simplex_tree_persistence_interface "Gudhi::Persistent_cohomology_interface<Gudhi::Simplex_tree<Gudhi::Simplex_tree_options_full_featured>>":
diff --git a/src/python/gudhi/simplex_tree.pyx b/src/python/gudhi/simplex_tree.pyx
index b8fabf78..a4914184 100644
--- a/src/python/gudhi/simplex_tree.pyx
+++ b/src/python/gudhi/simplex_tree.pyx
@@ -16,6 +16,9 @@ __author__ = "Vincent Rouvreau"
 __copyright__ = "Copyright (C) 2016 Inria"
 __license__ = "MIT"
 
+cdef bool callback(vector[int] simplex, void *blocker_func):
+    return (<object>blocker_func)(simplex)
+
 # SimplexTree python interface
 cdef class SimplexTree:
     """The simplex tree is an efficient and flexible data structure for
@@ -474,6 +477,27 @@ cdef class SimplexTree:
         persistence_result = self.pcohptr.get_persistence()
         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 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 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.
+
+        .. warning::
+            Several candidates of the same dimension may be inserted simultaneously before calling `block_simplex`, so
+            if you examine the complex in `block_simplex`, you may hit a few simplices of the same dimension that have
+            not been vetted by `block_simplex` yet, or have already been rejected but not yet removed.
+
+        :param max_dim: Expansion maximal dimension value.
+        :type max_dim: int
+        :param blocker_func: Blocker oracle.
+        :type blocker_func: Callable[[List[int]], bool]
+        """
+        self.get_ptr().expansion_with_blockers_callback(max_dim, callback, <void*>blocker_func)
 
     def persistence(self, homology_coeff_field=11, min_persistence=0, persistence_dim_max = False):
         """This function computes and returns the persistence of the simplicial complex.