From 1edb818b38ace05b230319227e60838b796ddfc5 Mon Sep 17 00:00:00 2001
From: ROUVREAU Vincent <vincent.rouvreau@inria.fr>
Date: Thu, 13 Feb 2020 11:08:44 +0100
Subject: simplex tree skeleton iterator

---
 src/python/gudhi/simplex_tree.pxd | 10 +++++++++-
 src/python/gudhi/simplex_tree.pyx | 15 ++++++---------
 2 files changed, 15 insertions(+), 10 deletions(-)

(limited to 'src/python/gudhi')

diff --git a/src/python/gudhi/simplex_tree.pxd b/src/python/gudhi/simplex_tree.pxd
index 1b0dc881..66c173a6 100644
--- a/src/python/gudhi/simplex_tree.pxd
+++ b/src/python/gudhi/simplex_tree.pxd
@@ -24,6 +24,13 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi":
     cdef cppclass Simplex_tree_simplex_handle "Gudhi::Simplex_tree_interface<Gudhi::Simplex_tree_options_full_featured>::Simplex_handle":
         pass
 
+    cdef cppclass Simplex_tree_skeleton_iterator "Gudhi::Simplex_tree_interface<Gudhi::Simplex_tree_options_full_featured>::Skeleton_simplex_iterator":
+        Simplex_tree_skeleton_iterator()
+        Simplex_tree_simplex_handle& operator*()
+        Simplex_tree_skeleton_iterator operator++()
+        bint operator!=(Simplex_tree_skeleton_iterator)
+
+
     cdef cppclass Simplex_tree_interface_full_featured "Gudhi::Simplex_tree_interface<Gudhi::Simplex_tree_options_full_featured>":
         Simplex_tree()
         double simplex_filtration(vector[int] simplex)
@@ -37,7 +44,6 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi":
         bool find_simplex(vector[int] simplex)
         bool insert_simplex_and_subfaces(vector[int] simplex,
                                          double filtration)
-        vector[pair[vector[int], double]] get_skeleton(int dimension)
         vector[pair[vector[int], double]] get_star(vector[int] simplex)
         vector[pair[vector[int], double]] get_cofaces(vector[int] simplex,
                                                           int dimension)
@@ -49,6 +55,8 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi":
         pair[vector[int], double] get_simplex_and_filtration(Simplex_tree_simplex_handle f_simplex)
         vector[Simplex_tree_simplex_handle].const_iterator get_filtration_iterator_begin()
         vector[Simplex_tree_simplex_handle].const_iterator get_filtration_iterator_end()
+        Simplex_tree_skeleton_iterator get_skeleton_iterator_begin(int dimension)
+        Simplex_tree_skeleton_iterator get_skeleton_iterator_end(int dimension)
 
 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 308b3d2d..efac2d80 100644
--- a/src/python/gudhi/simplex_tree.pyx
+++ b/src/python/gudhi/simplex_tree.pyx
@@ -231,15 +231,12 @@ cdef class SimplexTree:
         :returns:  The (simplices of the) skeleton of a maximum dimension.
         :rtype:  list of tuples(simplex, filtration)
         """
-        cdef vector[pair[vector[int], double]] skeleton \
-            = self.get_ptr().get_skeleton(<int>dimension)
-        ct = []
-        for filtered_simplex in skeleton:
-            v = []
-            for vertex in filtered_simplex.first:
-                v.append(vertex)
-            ct.append((v, filtered_simplex.second))
-        return ct
+        cdef Simplex_tree_skeleton_iterator it = self.get_ptr().get_skeleton_iterator_begin(dimension)
+        cdef Simplex_tree_skeleton_iterator end = self.get_ptr().get_skeleton_iterator_end(dimension)
+
+        while it != end:
+            yield self.get_ptr().get_simplex_and_filtration(dereference(it))
+            preincrement(it)
 
     def get_star(self, simplex):
         """This function returns the star of a given N-simplex.
-- 
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