fixed Vincent's comments

3 files changed, 92 insertions, 10 deletions

diff --git a/src/python/gudhi/simplex_tree.pxd b/src/python/gudhi/simplex_tree.pxd
index 4393047f..7aa16926 100644
--- a/src/python/gudhi/simplex_tree.pxd
+++ b/src/python/gudhi/simplex_tree.pxd
@@ -44,7 +44,7 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi":
         bool prune_above_filtration(double filtration)
         bool make_filtration_non_decreasing()
         void extend_filtration()
-        vector[vector[pair[int, pair[double, double]]]] convert(vector[pair[int, pair[double, double]]])
+        vector[vector[pair[int, pair[double, double]]]] compute_extended_persistence_subdiagrams(vector[pair[int, pair[double, double]]])
 
 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 cfab14f4..e429e28a 100644
--- a/src/python/gudhi/simplex_tree.pyx
+++ b/src/python/gudhi/simplex_tree.pyx
@@ -387,17 +387,21 @@ cdef class SimplexTree:
         return self.get_ptr().make_filtration_non_decreasing()
 
     def extend_filtration(self):
-        """ This function extends filtration for computing extended persistence.
+        """ Extend filtration for computing extended persistence. This function only uses the filtration values at the 0-dimensional simplices, and computes the extended persistence diagram induced by the lower-star filtration computed with these values. Note that after calling this function, the filtration values are actually modified. The function :func:`compute_extended_persistence_subdiagrams()<gudhi.SimplexTree.compute_extended_persistence_subdiagrams>` retrieves the original values and separates the extended persistence diagram points w.r.t. their types (Ord, Rel, Ext+, Ext-) and should always be called after computing the persistent homology of the extended simplicial complex.
         """
         return self.get_ptr().extend_filtration()
 
-    def convert(self, dgm):
-        """This function retrieves good values for extended persistence, and separate the diagrams into the ordinary, relative, extended+ and extended- subdiagrams. Need extend_filtration to be called first!
+    def compute_extended_persistence_subdiagrams(self, dgm):
+        """This function retrieves good values for extended persistence, and separate the diagrams into the ordinary, relative, extended+ and extended- subdiagrams.
 
-        :param dgm: Persistence diagram obtained after calling this->extend_filtration and this->get_persistence.
+        :param dgm: Persistence diagram obtained after calling :func:`extend_filtration()<gudhi.SimplexTree.extend_filtration>` and :func:`persistence()<gudhi.SimplexTree.persistence>`.
         :returns: A vector of four persistence diagrams. The first one is Ordinary, the second one is Relative, the third one is Extended+ and the fourth one is Extended-.
+
+        .. note::
+
+            This function should be called only after calling :func:`extend_filtration()<gudhi.SimplexTree.extend_filtration>` and :func:`persistence()<gudhi.SimplexTree.persistence>`.
         """
-        return self.get_ptr().convert(dgm)
+        return self.get_ptr().compute_extended_persistence_subdiagrams(dgm)
 
 
     def persistence(self, homology_coeff_field=11, min_persistence=0, persistence_dim_max = False):
diff --git a/src/python/test/test_simplex_tree.py b/src/python/test/test_simplex_tree.py
index 1822c43b..7e3d843e 100755
--- a/src/python/test/test_simplex_tree.py
+++ b/src/python/test/test_simplex_tree.py
@@ -244,7 +244,85 @@ def test_make_filtration_non_decreasing():
     assert st.filtration([0, 1, 6]) == 1.0
     assert st.filtration([0, 1]) == 1.0
     assert st.filtration([0]) == 1.0
-    assert st.filtration([1]) == 1.0
-    assert st.filtration([3, 4, 5]) == 2.0
-    assert st.filtration([3, 4]) == 2.0
-    assert st.filtration([4, 5]) == 2.0
+
+def test_extend_filtration():
+
+    # Inserted simplex:
+    #      5   4
+    #      o   o
+    #     / \ /
+    #    o   o
+    #   /2\ /3
+    #  o   o        
+    #  1   0        
+
+    st = SimplexTree()                                                                                                                     
+    st.insert([0,2])
+    st.insert([1,2])
+    st.insert([0,3])
+    st.insert([2,5])
+    st.insert([3,4])
+    st.insert([3,5])                                                                                                         
+    st.assign_filtration([0], 1.)                                                                                                                
+    st.assign_filtration([1], 2.)                                                                                                                
+    st.assign_filtration([2], 3.)                                                                                                                
+    st.assign_filtration([3], 4.)                                                                                                                
+    st.assign_filtration([4], 5.)                                                                                                                
+    st.assign_filtration([5], 6.)                                                                                                                
+
+    assert st.get_filtration() == [                                                                                                                         
+        ([0, 2], 0.0), 
+        ([1, 2], 0.0), 
+        ([0, 3], 0.0), 
+        ([3, 4], 0.0), 
+        ([2, 5], 0.0), 
+        ([3, 5], 0.0), 
+        ([0], 1.0), 
+        ([1], 2.0), 
+        ([2], 3.0), 
+        ([3], 4.0), 
+        ([4], 5.0), 
+        ([5], 6.0)
+    ]
+        
+
+    st.extend_filtration()
+                                                                                                                      
+    assert st.get_filtration() == [                                                                                                                         
+        ([6], -3.0), 
+        ([0], -2.0), 
+        ([1], -1.8), 
+        ([2], -1.6), 
+        ([0, 2], -1.6), 
+        ([1, 2], -1.6), 
+        ([3], -1.4), 
+        ([0, 3], -1.4), 
+        ([4], -1.2), 
+        ([3, 4], -1.2), 
+        ([5], -1.0), 
+        ([2, 5], -1.0), 
+        ([3, 5], -1.0), 
+        ([5, 6], 1.0), 
+        ([4, 6], 1.2), 
+        ([3, 6], 1.4), 
+        ([3, 4, 6], 1.4),
+        ([3, 5, 6], 1.4), 
+        ([2, 6], 1.6), 
+        ([2, 5, 6], 1.6), 
+        ([1, 6], 1.8), 
+        ([1, 2, 6], 1.8), 
+        ([0, 6], 2.0), 
+        ([0, 2, 6], 2.0), 
+        ([0, 3, 6], 2.0)
+    ]
+
+
+    dgm = st.persistence()
+    L = st.compute_extended_persistence_subdiagrams(dgm)
+    assert L == [
+        [(0, (1.9999999999999998, 2.9999999999999996))], 
+        [(1, (5.0, 4.0))], 
+        [(0, (1.0, 6.0))], 
+        [(1, (6.0, 1.0))]
+    ]
+