expansion method and its associated test

git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/gudhi/branches/ST_cythonize@2215 636b058d-ea47-450e-bf9e-a15bfbe3eedb

Former-commit-id: 32ad429f301b35c064eadef36dbe4e7f64f6490e

1 files changed, 20 insertions, 0 deletions

diff --git a/src/cython/cython/simplex_tree.pyx b/src/cython/cython/simplex_tree.pyx
index bb6fd1db..489c711f 100644
--- a/src/cython/cython/simplex_tree.pyx
+++ b/src/cython/cython/simplex_tree.pyx
@@ -52,6 +52,7 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi":
         vector[pair[vector[int], double]] get_cofaces(vector[int] simplex,
                                                           int dimension)
         void remove_maximal_simplex(vector[int] simplex)
+        void expansion(int max_dim)
 
 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>>":
@@ -304,6 +305,25 @@ cdef class SimplexTree:
         """
         self.thisptr.remove_maximal_simplex(simplex)
 
+    def expansion(self, max_dim):
+        """Expands the Simplex_tree containing only its one skeleton
+        until dimension max_dim.
+
+        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 Simplex_tree must contain no simplex of dimension bigger than
+        1 when calling the method.
+
+        :param max_dim: The maximal dimension.
+        :type max_dim: int.
+        """
+        self.thisptr.expansion(max_dim)
+
     def persistence(self, homology_coeff_field=11, min_persistence=0, persistence_dim_max = False):
         """This function returns the persistence of the simplicial complex.