Streamline initialize_filtration

30 files changed, 48 insertions, 140 deletions

diff --git a/src/Alpha_complex/test/Alpha_complex_unit_test.cpp b/src/Alpha_complex/test/Alpha_complex_unit_test.cpp
index da1d8004..4b37e4bd 100644
--- a/src/Alpha_complex/test/Alpha_complex_unit_test.cpp
+++ b/src/Alpha_complex/test/Alpha_complex_unit_test.cpp
@@ -188,9 +188,6 @@ BOOST_AUTO_TEST_CASE(Alpha_complex_from_points) {
   
   // Test after prune_above_filtration
   bool modified = simplex_tree.prune_above_filtration(0.6);
-  if (modified) {
-    simplex_tree.initialize_filtration();
-  }
   BOOST_CHECK(modified);
   
   // Another way to check num_simplices
diff --git a/src/Alpha_complex/utilities/alpha_complex_3d_persistence.cpp b/src/Alpha_complex/utilities/alpha_complex_3d_persistence.cpp
index e93c412e..91899040 100644
--- a/src/Alpha_complex/utilities/alpha_complex_3d_persistence.cpp
+++ b/src/Alpha_complex/utilities/alpha_complex_3d_persistence.cpp
@@ -222,9 +222,6 @@ int main(int argc, char **argv) {
       break;
   }
 
-  // Sort the simplices in the order of the filtration
-  simplex_tree.initialize_filtration();
-
   std::clog << "Simplex_tree dim: " << simplex_tree.dimension() << std::endl;
   // Compute the persistence diagram of the complex
   Persistent_cohomology pcoh(simplex_tree, true);
diff --git a/src/Alpha_complex/utilities/alpha_complex_persistence.cpp b/src/Alpha_complex/utilities/alpha_complex_persistence.cpp
index be60ff78..7c898dfd 100644
--- a/src/Alpha_complex/utilities/alpha_complex_persistence.cpp
+++ b/src/Alpha_complex/utilities/alpha_complex_persistence.cpp
@@ -75,9 +75,6 @@ int main(int argc, char **argv) {
   std::clog << "Simplicial complex is of dimension " << simplex.dimension() << " - " << simplex.num_simplices()
             << " simplices - " << simplex.num_vertices() << " vertices." << std::endl;
 
-  // Sort the simplices in the order of the filtration
-  simplex.initialize_filtration();
-
   std::clog << "Simplex_tree dim: " << simplex.dimension() << std::endl;
   // Compute the persistence diagram of the complex
   Gudhi::persistent_cohomology::Persistent_cohomology<Simplex_tree, Gudhi::persistent_cohomology::Field_Zp> pcoh(
diff --git a/src/Bottleneck_distance/example/alpha_rips_persistence_bottleneck_distance.cpp b/src/Bottleneck_distance/example/alpha_rips_persistence_bottleneck_distance.cpp
index 4769eca3..ceb9e226 100644
--- a/src/Bottleneck_distance/example/alpha_rips_persistence_bottleneck_distance.cpp
+++ b/src/Bottleneck_distance/example/alpha_rips_persistence_bottleneck_distance.cpp
@@ -71,9 +71,6 @@ int main(int argc, char * argv[]) {
   std::clog << "The Rips complex contains " << rips_stree.num_simplices() << " simplices and has dimension "
             << rips_stree.dimension() << " \n";
 
-  // Sort the simplices in the order of the filtration
-  rips_stree.initialize_filtration();
-
   // Compute the persistence diagram of the complex
   Persistent_cohomology rips_pcoh(rips_stree);
   // initializes the coefficient field for homology
@@ -92,9 +89,6 @@ int main(int argc, char * argv[]) {
   std::clog << "The Alpha complex contains " << alpha_stree.num_simplices() << " simplices and has dimension "
             << alpha_stree.dimension() << " \n";
 
-  // Sort the simplices in the order of the filtration
-  alpha_stree.initialize_filtration();
-
   // Compute the persistence diagram of the complex
   Persistent_cohomology alpha_pcoh(alpha_stree);
   // initializes the coefficient field for homology
diff --git a/src/Persistent_cohomology/example/custom_persistence_sort.cpp b/src/Persistent_cohomology/example/custom_persistence_sort.cpp
index 87e9c207..410cd987 100644
--- a/src/Persistent_cohomology/example/custom_persistence_sort.cpp
+++ b/src/Persistent_cohomology/example/custom_persistence_sort.cpp
@@ -86,9 +86,6 @@ int main(int argc, char **argv) {
         " - " << simplex.num_simplices() << " simplices - " <<
         simplex.num_vertices() << " vertices." << std::endl;
 
-    // Sort the simplices in the order of the filtration
-    simplex.initialize_filtration();
-
     std::clog << "Simplex_tree dim: " << simplex.dimension() << std::endl;
 
     Persistent_cohomology pcoh(simplex);
diff --git a/src/Persistent_cohomology/example/persistence_from_file.cpp b/src/Persistent_cohomology/example/persistence_from_file.cpp
index 79108730..38c44514 100644
--- a/src/Persistent_cohomology/example/persistence_from_file.cpp
+++ b/src/Persistent_cohomology/example/persistence_from_file.cpp
@@ -59,9 +59,6 @@ int main(int argc, char * argv[]) {
   std::clog << std::endl;
   }*/
 
-  // Sort the simplices in the order of the filtration
-  simplex_tree.initialize_filtration();
-
   // Compute the persistence diagram of the complex
   Persistent_cohomology< Simplex_tree<>, Field_Zp > pcoh(simplex_tree);
   // initializes the coefficient field for homology
diff --git a/src/Persistent_cohomology/example/plain_homology.cpp b/src/Persistent_cohomology/example/plain_homology.cpp
index 4d329020..236b67de 100644
--- a/src/Persistent_cohomology/example/plain_homology.cpp
+++ b/src/Persistent_cohomology/example/plain_homology.cpp
@@ -59,9 +59,6 @@ int main() {
   st.insert_simplex_and_subfaces(edge35);
   st.insert_simplex(vertex4);
 
-  // Sort the simplices in the order of the filtration
-  st.initialize_filtration();
-
   // Class for homology computation
   // By default, since the complex has dimension 1, only 0-dimensional homology would be computed.
   // Here we also want persistent homology to be computed for the maximal dimension in the complex (persistence_dim_max = true)
diff --git a/src/Persistent_cohomology/example/rips_multifield_persistence.cpp b/src/Persistent_cohomology/example/rips_multifield_persistence.cpp
index e2e2c0a5..2edf5bc4 100644
--- a/src/Persistent_cohomology/example/rips_multifield_persistence.cpp
+++ b/src/Persistent_cohomology/example/rips_multifield_persistence.cpp
@@ -59,9 +59,6 @@ int main(int argc, char * argv[]) {
   std::clog << "The complex contains " << simplex_tree.num_simplices() << " simplices \n";
   std::clog << "   and has dimension " << simplex_tree.dimension() << " \n";
 
-  // Sort the simplices in the order of the filtration
-  simplex_tree.initialize_filtration();
-
   // Compute the persistence diagram of the complex
   Persistent_cohomology pcoh(simplex_tree);
   // initializes the coefficient field for homology
diff --git a/src/Persistent_cohomology/example/rips_persistence_step_by_step.cpp b/src/Persistent_cohomology/example/rips_persistence_step_by_step.cpp
index 7da9f15d..a503d983 100644
--- a/src/Persistent_cohomology/example/rips_persistence_step_by_step.cpp
+++ b/src/Persistent_cohomology/example/rips_persistence_step_by_step.cpp
@@ -76,9 +76,6 @@ int main(int argc, char * argv[]) {
   std::clog << "The complex contains " << st.num_simplices() << " simplices \n";
   std::clog << "   and has dimension " << st.dimension() << " \n";
 
-  // Sort the simplices in the order of the filtration
-  st.initialize_filtration();
-
   // Compute the persistence diagram of the complex
   Persistent_cohomology pcoh(st);
   // initializes the coefficient field for homology
diff --git a/src/Persistent_cohomology/include/gudhi/Persistent_cohomology.h b/src/Persistent_cohomology/include/gudhi/Persistent_cohomology.h
index ca4bc10d..bc111f94 100644
--- a/src/Persistent_cohomology/include/gudhi/Persistent_cohomology.h
+++ b/src/Persistent_cohomology/include/gudhi/Persistent_cohomology.h
@@ -561,7 +561,6 @@ class Persistent_cohomology {
   void output_diagram(std::ostream& ostream = std::cout) {
     cmp_intervals_by_length cmp(cpx_);
     std::sort(std::begin(persistent_pairs_), std::end(persistent_pairs_), cmp);
-    bool has_infinity = std::numeric_limits<Filtration_value>::has_infinity;
     for (auto pair : persistent_pairs_) {
       ostream << get<2>(pair) << "  " << cpx_->dimension(get<0>(pair)) << " "
         << cpx_->filtration(get<0>(pair)) << " "
@@ -573,7 +572,6 @@ class Persistent_cohomology {
     std::ofstream diagram_out(diagram_name.c_str());
     cmp_intervals_by_length cmp(cpx_);
     std::sort(std::begin(persistent_pairs_), std::end(persistent_pairs_), cmp);
-    bool has_infinity = std::numeric_limits<Filtration_value>::has_infinity;
     for (auto pair : persistent_pairs_) {
       diagram_out << cpx_->dimension(get<0>(pair)) << " "
             << cpx_->filtration(get<0>(pair)) << " "
diff --git a/src/Rips_complex/utilities/rips_correlation_matrix_persistence.cpp b/src/Rips_complex/utilities/rips_correlation_matrix_persistence.cpp
index 67f921a6..b473738e 100644
--- a/src/Rips_complex/utilities/rips_correlation_matrix_persistence.cpp
+++ b/src/Rips_complex/utilities/rips_correlation_matrix_persistence.cpp
@@ -71,9 +71,6 @@ int main(int argc, char* argv[]) {
   std::clog << "The complex contains " << simplex_tree.num_simplices() << " simplices \n";
   std::clog << "   and has dimension " << simplex_tree.dimension() << " \n";
 
-  // Sort the simplices in the order of the filtration
-  simplex_tree.initialize_filtration();
-
   // Compute the persistence diagram of the complex
   Persistent_cohomology pcoh(simplex_tree);
   // initializes the coefficient field for homology
diff --git a/src/Rips_complex/utilities/rips_distance_matrix_persistence.cpp b/src/Rips_complex/utilities/rips_distance_matrix_persistence.cpp
index 4ad19675..6306755d 100644
--- a/src/Rips_complex/utilities/rips_distance_matrix_persistence.cpp
+++ b/src/Rips_complex/utilities/rips_distance_matrix_persistence.cpp
@@ -50,9 +50,6 @@ int main(int argc, char* argv[]) {
   std::clog << "The complex contains " << simplex_tree.num_simplices() << " simplices \n";
   std::clog << "   and has dimension " << simplex_tree.dimension() << " \n";
 
-  // Sort the simplices in the order of the filtration
-  simplex_tree.initialize_filtration();
-
   // Compute the persistence diagram of the complex
   Persistent_cohomology pcoh(simplex_tree);
   // initializes the coefficient field for homology
diff --git a/src/Rips_complex/utilities/rips_persistence.cpp b/src/Rips_complex/utilities/rips_persistence.cpp
index 4cc63d3c..9d7490b3 100644
--- a/src/Rips_complex/utilities/rips_persistence.cpp
+++ b/src/Rips_complex/utilities/rips_persistence.cpp
@@ -52,9 +52,6 @@ int main(int argc, char* argv[]) {
   std::clog << "The complex contains " << simplex_tree.num_simplices() << " simplices \n";
   std::clog << "   and has dimension " << simplex_tree.dimension() << " \n";
 
-  // Sort the simplices in the order of the filtration
-  simplex_tree.initialize_filtration();
-
   // Compute the persistence diagram of the complex
   Persistent_cohomology pcoh(simplex_tree);
   // initializes the coefficient field for homology
diff --git a/src/Rips_complex/utilities/sparse_rips_persistence.cpp b/src/Rips_complex/utilities/sparse_rips_persistence.cpp
index 40606158..ac935b41 100644
--- a/src/Rips_complex/utilities/sparse_rips_persistence.cpp
+++ b/src/Rips_complex/utilities/sparse_rips_persistence.cpp
@@ -54,9 +54,6 @@ int main(int argc, char* argv[]) {
   std::clog << "The complex contains " << simplex_tree.num_simplices() << " simplices \n";
   std::clog << "   and has dimension " << simplex_tree.dimension() << " \n";
 
-  // Sort the simplices in the order of the filtration
-  simplex_tree.initialize_filtration();
-
   // Compute the persistence diagram of the complex
   Persistent_cohomology pcoh(simplex_tree);
   // initializes the coefficient field for homology
diff --git a/src/Simplex_tree/include/gudhi/Simplex_tree.h b/src/Simplex_tree/include/gudhi/Simplex_tree.h
index b455ae31..43250795 100644
--- a/src/Simplex_tree/include/gudhi/Simplex_tree.h
+++ b/src/Simplex_tree/include/gudhi/Simplex_tree.h
@@ -142,7 +142,10 @@ class Simplex_tree {
 
  public:
   /** \brief Handle type to a simplex contained in the simplicial complex represented
-   * by the simplex tree. */
+   * by the simplex tree.
+   *
+   * They are essentially pointers into internal vectors, and any insertion or removal
+   * of a simplex may invalidate any other Simplex_handle in the complex. */
   typedef typename Dictionary::iterator Simplex_handle;
 
  private:
@@ -255,11 +258,9 @@ class Simplex_tree {
    *
    * The filtration must be valid. If the filtration has not been initialized yet, the
    * method initializes it (i.e. order the simplices). If the complex has changed since the last time the filtration
-   * was initialized, please call `initialize_filtration()` to recompute it. */
+   * was initialized, please call `clear_filtration()` or `initialize_filtration()` to recompute it. */
   Filtration_simplex_range const& filtration_simplex_range(Indexing_tag = Indexing_tag()) {
-    if (filtration_vect_.empty()) {
-      initialize_filtration();
-    }
+    maybe_initialize_filtration();
     return filtration_vect_;
   }
 
@@ -877,15 +878,13 @@ class Simplex_tree {
   }
 
  public:
-  /** \brief Initializes the filtrations, i.e. sort the
-   * simplices according to their order in the filtration and initializes all Simplex_keys.
+  /** \brief Initializes the filtration cache, i.e. sorts the
+   * simplices according to their order in the filtration.
    *
-   * After calling this method, filtration_simplex_range() becomes valid, and each simplex is
-   * assigned a Simplex_key corresponding to its order in the filtration (from 0 to m-1 for a
-   * simplicial complex with m simplices).
+   * It always recomputes the cache, even if one already exists.
    *
-   * Will be automatically called when calling filtration_simplex_range()
-   * if the filtration has never been initialized yet. */
+   * Any insertion, deletion or change of filtration value invalidates this cache,
+   * which can be cleared with clear_filtration().  */
   void initialize_filtration() {
     filtration_vect_.clear();
     filtration_vect_.reserve(num_simplices());
@@ -907,6 +906,21 @@ class Simplex_tree {
     std::stable_sort(filtration_vect_.begin(), filtration_vect_.end(), is_before_in_filtration(this));
 #endif
   }
+  /** \brief Initializes the filtration cache if it isn't initialized yet.
+   *
+   * Automatically called by filtration_simplex_range(). */
+  void maybe_initialize_filtration() {
+    if (filtration_vect_.empty()) {
+      initialize_filtration();
+    }
+  }
+  /** \brief Clears the filtration cache produced by initialize_filtration().
+   *
+   * Useful when initialize_filtration() has already been called and we perform an operation
+   * (say an insertion) that invalidates the cache. */
+  void clear_filtration() {
+    filtration_vect_.clear();
+  }
 
  private:
   /** Recursive search of cofaces
@@ -1128,6 +1142,7 @@ class Simplex_tree {
    * 1 when calling the method. */
   void expansion(int max_dim) {
     if (max_dim <= 1) return;
+    clear_filtration(); // Drop the cache.
     dimension_ = max_dim;
     for (Dictionary_it root_it = root_.members_.begin();
          root_it != root_.members_.end(); ++root_it) {
@@ -1338,9 +1353,6 @@ class Simplex_tree {
   /** \brief This function ensures that each simplex has a higher filtration value than its faces by increasing the
    * filtration values.
    * @return True if any filtration value was modified, false if the filtration was already non-decreasing.
-   * \post Some simplex tree functions require the filtration to be valid. `make_filtration_non_decreasing()`
-   * function is not launching `initialize_filtration()` but returns the filtration modification information. If the
-   * complex has changed , please call `initialize_filtration()` to recompute it.
    * 
    * If a simplex has a `NaN` filtration value, it is considered lower than any other defined filtration value.
    */
@@ -1352,6 +1364,8 @@ class Simplex_tree {
         modified |= rec_make_filtration_non_decreasing(simplex.second.children());
       }
     }
+    if(modified)
+      clear_filtration(); // Drop the cache.
     return modified;
   }
 
@@ -1391,16 +1405,16 @@ class Simplex_tree {
  public:
   /** \brief Prune above filtration value given as parameter.
    * @param[in] filtration Maximum threshold value.
-   * @return The filtration modification information.
-   * \post Some simplex tree functions require the filtration to be valid. `prune_above_filtration()`
-   * function is not launching `initialize_filtration()` but returns the filtration modification information. If the
-   * complex has changed , please call `initialize_filtration()` to recompute it.
+   * @return True if any simplex was removed, false if all simplices already had a value below the threshold.
    * \post Note that the dimension of the simplicial complex may be lower after calling `prune_above_filtration()`
    * than it was before. However, `upper_bound_dimension()` will return the old value, which remains a valid upper
    * bound. If you care, you can call `dimension()` to recompute the exact dimension.
    */
   bool prune_above_filtration(Filtration_value filtration) {
-    return rec_prune_above_filtration(root(), filtration);
+    bool modified = rec_prune_above_filtration(root(), filtration);
+    if(modified)
+      clear_filtration(); // Drop the cache.
+    return modified;
   }
 
  private:
@@ -1467,7 +1481,6 @@ class Simplex_tree {
    * @param[in] sh Simplex handle on the maximal simplex to remove.
    * \pre Please check the simplex has no coface before removing it.
    * \exception std::invalid_argument In debug mode, if sh has children.
-   * \post Be aware that removing is shifting data in a flat_map (initialize_filtration to be done).
    * \post Note that the dimension of the simplicial complex may be lower after calling `remove_maximal_simplex()`
    * than it was before. However, `upper_bound_dimension()` will return the old value, which remains a valid upper
    * bound. If you care, you can call `dimension()` to recompute the exact dimension.
@@ -1539,6 +1552,7 @@ class Simplex_tree {
    * the original filtration values for each simplex.
    */
   Extended_filtration_data extend_filtration() {
+    clear_filtration(); // Drop the cache.
 
     // Compute maximum and minimum of filtration values
     Vertex_handle maxvert = std::numeric_limits<Vertex_handle>::min();
diff --git a/src/python/doc/simplex_tree_ref.rst b/src/python/doc/simplex_tree_ref.rst
index 9eb8c199..46b2c1e5 100644
--- a/src/python/doc/simplex_tree_ref.rst
+++ b/src/python/doc/simplex_tree_ref.rst
@@ -8,7 +8,6 @@ Simplex tree reference manual
 
 .. autoclass:: gudhi.SimplexTree
    :members:
-   :undoc-members:
    :show-inheritance:
 
    .. automethod:: gudhi.SimplexTree.__init__
diff --git a/src/python/example/alpha_complex_from_points_example.py b/src/python/example/alpha_complex_from_points_example.py
index 73faf17c..465632eb 100755
--- a/src/python/example/alpha_complex_from_points_example.py
+++ b/src/python/example/alpha_complex_from_points_example.py
@@ -46,9 +46,6 @@ if simplex_tree.find([4]):
 else:
     print("[4] Not found...")
 
-# Some insertions, simplex_tree needs to initialize filtrations
-simplex_tree.initialize_filtration()
-
 print("dimension=", simplex_tree.dimension())
 print("filtrations=")
 for simplex_with_filtration in simplex_tree.get_filtration():
diff --git a/src/python/example/simplex_tree_example.py b/src/python/example/simplex_tree_example.py
index 34833899..c4635dc5 100755
--- a/src/python/example/simplex_tree_example.py
+++ b/src/python/example/simplex_tree_example.py
@@ -42,7 +42,6 @@ print("simplices=")
 for simplex_with_filtration in st.get_simplices():
     print("(%s, %.2f)" % tuple(simplex_with_filtration))
 
-st.initialize_filtration()
 print("filtration=")
 for simplex_with_filtration in st.get_filtration():
     print("(%s, %.2f)" % tuple(simplex_with_filtration))
diff --git a/src/python/gudhi/simplex_tree.pxd b/src/python/gudhi/simplex_tree.pxd
index 595f22bb..7e3bba2b 100644
--- a/src/python/gudhi/simplex_tree.pxd
+++ b/src/python/gudhi/simplex_tree.pxd
@@ -48,8 +48,7 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi":
         int dimension()
         int upper_bound_dimension()
         bool find_simplex(vector[int] simplex)
-        bool insert_simplex_and_subfaces(vector[int] simplex,
-                                         double filtration)
+        bool insert(vector[int] simplex, double filtration)
         vector[pair[vector[int], double]] get_star(vector[int] simplex)
         vector[pair[vector[int], double]] get_cofaces(vector[int] simplex,
                                                           int dimension)
diff --git a/src/python/gudhi/simplex_tree.pyx b/src/python/gudhi/simplex_tree.pyx
index cc3753e1..a709980f 100644
--- a/src/python/gudhi/simplex_tree.pyx
+++ b/src/python/gudhi/simplex_tree.pyx
@@ -90,7 +90,7 @@ cdef class SimplexTree:
             (with more :meth:`assign_filtration` or
             :meth:`make_filtration_non_decreasing` for instance) before calling
             any function that relies on the filtration property, like
-            :meth:`initialize_filtration`.
+            :meth:`persistence`.
         """
         self.get_ptr().assign_simplex_filtration(simplex, filtration)
 
@@ -98,16 +98,7 @@ cdef class SimplexTree:
         """This function initializes and sorts the simplicial complex
         filtration vector.
 
-        .. note::
-
-            This function must be launched before
-            :func:`persistence()<gudhi.SimplexTree.persistence>`,
-            :func:`betti_numbers()<gudhi.SimplexTree.betti_numbers>`,
-            :func:`persistent_betti_numbers()<gudhi.SimplexTree.persistent_betti_numbers>`,
-            or :func:`get_filtration()<gudhi.SimplexTree.get_filtration>`
-            after :func:`inserting<gudhi.SimplexTree.insert>` or
-            :func:`removing<gudhi.SimplexTree.remove_maximal_simplex>`
-            simplices.
+        .. deprecated:: 3.2.0
         """
         self.get_ptr().initialize_filtration()
 
@@ -182,10 +173,7 @@ cdef class SimplexTree:
         :returns:  true if the simplex was found, false otherwise.
         :rtype:  bool
         """
-        cdef vector[int] csimplex
-        for i in simplex:
-            csimplex.push_back(i)
-        return self.get_ptr().find_simplex(csimplex)
+        return self.get_ptr().find_simplex(simplex)
 
     def insert(self, simplex, filtration=0.0):
         """This function inserts the given N-simplex and its subfaces with the
@@ -202,11 +190,7 @@ cdef class SimplexTree:
             otherwise (whatever its original filtration value).
         :rtype:  bool
         """
-        cdef vector[int] csimplex
-        for i in simplex:
-            csimplex.push_back(i)
-        return self.get_ptr().insert_simplex_and_subfaces(csimplex,
-                                                        <double>filtration)
+        return self.get_ptr().insert(simplex, <double>filtration)
 
     def get_simplices(self):
         """This function returns a generator with simplices and their given
@@ -308,11 +292,6 @@ cdef class SimplexTree:
 
         .. note::
 
-            Be aware that removing is shifting data in a flat_map
-            (:func:`initialize_filtration()<gudhi.SimplexTree.initialize_filtration>` to be done).
-
-        .. note::
-
             The dimension of the simplicial complex may be lower after calling
             remove_maximal_simplex than it was before. However,
             :func:`upper_bound_dimension()<gudhi.SimplexTree.upper_bound_dimension>`
@@ -334,16 +313,6 @@ cdef class SimplexTree:
 
         .. note::
 
-            Some simplex tree functions require the filtration to be valid.
-            prune_above_filtration function is not launching
-            :func:`initialize_filtration()<gudhi.SimplexTree.initialize_filtration>`
-            but returns the filtration modification
-            information. If the complex has changed , please call
-            :func:`initialize_filtration()<gudhi.SimplexTree.initialize_filtration>`
-            to recompute it.
-
-        .. note::
-
             Note that the dimension of the simplicial complex may be lower
             after calling
             :func:`prune_above_filtration()<gudhi.SimplexTree.prune_above_filtration>`
@@ -382,17 +351,6 @@ cdef class SimplexTree:
         :returns: True if any filtration value was modified,
             False if the filtration was already non-decreasing.
         :rtype: bool
-
-
-        .. note::
-
-            Some simplex tree functions require the filtration to be valid.
-            make_filtration_non_decreasing function is not launching
-            :func:`initialize_filtration()<gudhi.SimplexTree.initialize_filtration>`
-            but returns the filtration modification
-            information. If the complex has changed , please call
-            :func:`initialize_filtration()<gudhi.SimplexTree.initialize_filtration>`
-            to recompute it.
         """
         return self.get_ptr().make_filtration_non_decreasing()
 
diff --git a/src/python/include/Alpha_complex_interface.h b/src/python/include/Alpha_complex_interface.h
index 8614eee3..40de88f3 100644
--- a/src/python/include/Alpha_complex_interface.h
+++ b/src/python/include/Alpha_complex_interface.h
@@ -58,7 +58,6 @@ class Alpha_complex_interface {
 
   void create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double max_alpha_square) {
     alpha_complex_->create_complex(*simplex_tree, max_alpha_square);
-    simplex_tree->initialize_filtration();
   }
 
  private:
diff --git a/src/python/include/Euclidean_strong_witness_complex_interface.h b/src/python/include/Euclidean_strong_witness_complex_interface.h
index c1c72737..f94c51ef 100644
--- a/src/python/include/Euclidean_strong_witness_complex_interface.h
+++ b/src/python/include/Euclidean_strong_witness_complex_interface.h
@@ -50,12 +50,10 @@ class Euclidean_strong_witness_complex_interface {
   void create_simplex_tree(Gudhi::Simplex_tree<>* simplex_tree, double max_alpha_square,
                            std::size_t limit_dimension) {
     witness_complex_->create_complex(*simplex_tree, max_alpha_square, limit_dimension);
-    simplex_tree->initialize_filtration();
   }
 
   void create_simplex_tree(Gudhi::Simplex_tree<>* simplex_tree, double max_alpha_square) {
     witness_complex_->create_complex(*simplex_tree, max_alpha_square);
-    simplex_tree->initialize_filtration();
   }
 
   std::vector<double> get_point(unsigned vh) {
diff --git a/src/python/include/Euclidean_witness_complex_interface.h b/src/python/include/Euclidean_witness_complex_interface.h
index 5d7dbdc2..4411ae79 100644
--- a/src/python/include/Euclidean_witness_complex_interface.h
+++ b/src/python/include/Euclidean_witness_complex_interface.h
@@ -49,12 +49,10 @@ class Euclidean_witness_complex_interface {
 
   void create_simplex_tree(Gudhi::Simplex_tree<>* simplex_tree, double max_alpha_square, std::size_t limit_dimension) {
     witness_complex_->create_complex(*simplex_tree, max_alpha_square, limit_dimension);
-    simplex_tree->initialize_filtration();
   }
 
   void create_simplex_tree(Gudhi::Simplex_tree<>* simplex_tree, double max_alpha_square) {
     witness_complex_->create_complex(*simplex_tree, max_alpha_square);
-    simplex_tree->initialize_filtration();
   }
 
   std::vector<double> get_point(unsigned vh) {
diff --git a/src/python/include/Nerve_gic_interface.h b/src/python/include/Nerve_gic_interface.h
index 5e7f8ae6..ab14c318 100644
--- a/src/python/include/Nerve_gic_interface.h
+++ b/src/python/include/Nerve_gic_interface.h
@@ -29,7 +29,6 @@ class Nerve_gic_interface : public Cover_complex<std::vector<double>> {
  public:
   void create_simplex_tree(Simplex_tree_interface<>* simplex_tree) {
     create_complex(*simplex_tree);
-    simplex_tree->initialize_filtration();
   }
   void set_cover_from_Euclidean_Voronoi(int m) {
     set_cover_from_Voronoi(Gudhi::Euclidean_distance(), m);
diff --git a/src/python/include/Rips_complex_interface.h b/src/python/include/Rips_complex_interface.h
index a66b0e5b..d98b0226 100644
--- a/src/python/include/Rips_complex_interface.h
+++ b/src/python/include/Rips_complex_interface.h
@@ -53,7 +53,6 @@ class Rips_complex_interface {
       rips_complex_->create_complex(*simplex_tree, dim_max);
     else
       sparse_rips_complex_->create_complex(*simplex_tree, dim_max);
-    simplex_tree->initialize_filtration();
   }
 
  private:
diff --git a/src/python/include/Simplex_tree_interface.h b/src/python/include/Simplex_tree_interface.h
index 1a18aed6..5b456baa 100644
--- a/src/python/include/Simplex_tree_interface.h
+++ b/src/python/include/Simplex_tree_interface.h
@@ -43,16 +43,19 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> {
 
   Extended_filtration_data efd;
   
-  bool find_simplex(const Simplex& vh) {
-    return (Base::find(vh) != Base::null_simplex());
+  bool find_simplex(const Simplex& simplex) {
+    return (Base::find(simplex) != Base::null_simplex());
   }
 
-  void assign_simplex_filtration(const Simplex& vh, Filtration_value filtration) {
-    Base::assign_filtration(Base::find(vh), filtration);
+  void assign_simplex_filtration(const Simplex& simplex, Filtration_value filtration) {
+    Base::assign_filtration(Base::find(simplex), filtration);
+    Base::clear_filtration();
   }
 
   bool insert(const Simplex& simplex, Filtration_value filtration = 0) {
     Insertion_result result = Base::insert_simplex_and_subfaces(simplex, filtration);
+    if (result.first != Base::null_simplex())
+      Base::clear_filtration();
     return (result.second);
   }
 
@@ -86,7 +89,7 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> {
 
   void remove_maximal_simplex(const Simplex& simplex) {
     Base::remove_maximal_simplex(Base::find(simplex));
-    Base::initialize_filtration();
+    Base::clear_filtration();
   }
 
   Simplex_and_filtration get_simplex_and_filtration(Simplex_handle f_simplex) {
@@ -123,7 +126,6 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> {
 
   void compute_extended_filtration() {
     this->efd = this->extend_filtration();
-    this->initialize_filtration();
     return;
   }
 
@@ -158,7 +160,6 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> {
   }
 
   void create_persistence(Gudhi::Persistent_cohomology_interface<Base>* pcoh) {
-    Base::initialize_filtration();
     pcoh = new Gudhi::Persistent_cohomology_interface<Base>(*this);
   }
 
diff --git a/src/python/include/Strong_witness_complex_interface.h b/src/python/include/Strong_witness_complex_interface.h
index cda5b514..e9ab0c7b 100644
--- a/src/python/include/Strong_witness_complex_interface.h
+++ b/src/python/include/Strong_witness_complex_interface.h
@@ -41,13 +41,11 @@ class Strong_witness_complex_interface {
   void create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double  max_alpha_square,
                            std::size_t limit_dimension) {
     witness_complex_->create_complex(*simplex_tree, max_alpha_square, limit_dimension);
-    simplex_tree->initialize_filtration();
   }
 
   void create_simplex_tree(Simplex_tree_interface<>* simplex_tree,
                            double  max_alpha_square) {
     witness_complex_->create_complex(*simplex_tree, max_alpha_square);
-    simplex_tree->initialize_filtration();
   }
 
  private:
diff --git a/src/python/include/Tangential_complex_interface.h b/src/python/include/Tangential_complex_interface.h
index 698226cc..b1afce94 100644
--- a/src/python/include/Tangential_complex_interface.h
+++ b/src/python/include/Tangential_complex_interface.h
@@ -90,7 +90,6 @@ class Tangential_complex_interface {
 
   void create_simplex_tree(Simplex_tree<>* simplex_tree) {
     tangential_complex_->create_complex<Gudhi::Simplex_tree<Gudhi::Simplex_tree_options_full_featured>>(*simplex_tree);
-    simplex_tree->initialize_filtration();
   }
 
   void set_max_squared_edge_length(double max_squared_edge_length) {
diff --git a/src/python/include/Witness_complex_interface.h b/src/python/include/Witness_complex_interface.h
index 45e14253..76947e53 100644
--- a/src/python/include/Witness_complex_interface.h
+++ b/src/python/include/Witness_complex_interface.h
@@ -41,13 +41,11 @@ class Witness_complex_interface {
   void create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double  max_alpha_square,
                            std::size_t limit_dimension) {
     witness_complex_->create_complex(*simplex_tree, max_alpha_square, limit_dimension);
-    simplex_tree->initialize_filtration();
   }
 
   void create_simplex_tree(Simplex_tree_interface<>* simplex_tree,
                            double  max_alpha_square) {
     witness_complex_->create_complex(*simplex_tree, max_alpha_square);
-    simplex_tree->initialize_filtration();
   }
 
  private:
diff --git a/src/python/test/test_simplex_tree.py b/src/python/test/test_simplex_tree.py
index 70b26e97..2137d822 100755
--- a/src/python/test/test_simplex_tree.py
+++ b/src/python/test/test_simplex_tree.py
@@ -46,7 +46,6 @@ def test_insertion():
     assert st.find([2, 3]) == False
 
     # filtration test
-    st.initialize_filtration()
     assert st.filtration([0, 1, 2]) == 4.0
     assert st.filtration([0, 2]) == 4.0
     assert st.filtration([1, 2]) == 4.0
@@ -93,7 +92,6 @@ def test_insertion():
     assert st.find([1]) == True
     assert st.find([2]) == True
 
-    st.initialize_filtration()
     assert st.persistence(persistence_dim_max=True) == [
         (1, (4.0, float("inf"))),
         (0, (0.0, float("inf"))),
@@ -151,7 +149,6 @@ def test_expansion():
     st.expansion(3)
     assert st.num_vertices() == 7
     assert st.num_simplices() == 22
-    st.initialize_filtration()
 
     assert list(st.get_filtration()) == [
         ([2], 0.1),