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-rw-r--r--src/Simplex_tree/include/gudhi/Simplex_tree.h31
-rw-r--r--src/Simplex_tree/test/simplex_tree_unit_test.cpp51
-rw-r--r--src/python/gudhi/simplex_tree.pxd1
-rw-r--r--src/python/gudhi/simplex_tree.pyx22
-rwxr-xr-xsrc/python/test/test_simplex_tree.py26
5 files changed, 125 insertions, 6 deletions
diff --git a/src/Simplex_tree/include/gudhi/Simplex_tree.h b/src/Simplex_tree/include/gudhi/Simplex_tree.h
index 889dbd00..85d6c3b0 100644
--- a/src/Simplex_tree/include/gudhi/Simplex_tree.h
+++ b/src/Simplex_tree/include/gudhi/Simplex_tree.h
@@ -1667,6 +1667,37 @@ class Simplex_tree {
return sh; // None of its faces has the same filtration.
}
+ public:
+ /** \brief This function resets the filtration value of all the simplices of dimension at least min_dim. Resets all
+ * the Simplex_tree when `min_dim = 0`.
+ * `reset_filtration` may break the filtration property with `min_dim > 0`, and it is the user's responsibility to
+ * make it a valid filtration (using a large enough `filt_value`, or calling `make_filtration_non_decreasing`
+ * afterwards for instance).
+ * @param[in] filt_value The new filtration value.
+ * @param[in] min_dim The minimal dimension. Default value is 0.
+ */
+ void reset_filtration(Filtration_value filt_value, int min_dim = 0) {
+ rec_reset_filtration(&root_, filt_value, min_dim);
+ clear_filtration(); // Drop the cache.
+ }
+
+ private:
+ /** \brief Recursively resets filtration value when minimal depth <= 0.
+ * @param[in] sib Siblings to be parsed.
+ * @param[in] filt_value The new filtration value.
+ * @param[in] min_depth The minimal depth.
+ */
+ void rec_reset_filtration(Siblings * sib, Filtration_value filt_value, int min_depth) {
+ for (auto sh = sib->members().begin(); sh != sib->members().end(); ++sh) {
+ if (min_depth <= 0) {
+ sh->second.assign_filtration(filt_value);
+ }
+ if (has_children(sh)) {
+ rec_reset_filtration(sh->second.children(), filt_value, min_depth - 1);
+ }
+ }
+ }
+
private:
Vertex_handle null_vertex_;
/** \brief Total number of simplices in the complex, without the empty simplex.*/
diff --git a/src/Simplex_tree/test/simplex_tree_unit_test.cpp b/src/Simplex_tree/test/simplex_tree_unit_test.cpp
index 9b5fa8fe..bdd41d34 100644
--- a/src/Simplex_tree/test/simplex_tree_unit_test.cpp
+++ b/src/Simplex_tree/test/simplex_tree_unit_test.cpp
@@ -940,3 +940,54 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(generators, typeST, list_of_tested_variants) {
BOOST_CHECK(st.edge_with_same_filtration(st.find({1,5}))==st.find({1,5}));
}
}
+
+BOOST_AUTO_TEST_CASE_TEMPLATE(simplex_tree_reset_filtration, typeST, list_of_tested_variants) {
+ std::clog << "********************************************************************" << std::endl;
+ std::clog << "TEST RESET FILTRATION" << std::endl;
+ typeST st;
+
+ st.insert_simplex_and_subfaces({2, 1, 0}, 3.);
+ st.insert_simplex_and_subfaces({3, 0}, 2.);
+ st.insert_simplex_and_subfaces({3, 4, 5}, 3.);
+ st.insert_simplex_and_subfaces({0, 1, 6, 7}, 4.);
+
+ /* Inserted simplex: */
+ /* 1 6 */
+ /* o---o */
+ /* /X\7/ */
+ /* o---o---o---o */
+ /* 2 0 3\X/4 */
+ /* o */
+ /* 5 */
+
+ for (auto f_simplex : st.skeleton_simplex_range(3)) {
+ std::clog << "vertex = (";
+ for (auto vertex : st.simplex_vertex_range(f_simplex)) {
+ std::clog << vertex << ",";
+ }
+ std::clog << ") - filtration = " << st.filtration(f_simplex);
+ std::clog << " - dimension = " << st.dimension(f_simplex) << std::endl;
+ // Guaranteed by construction
+ BOOST_CHECK(st.filtration(f_simplex) >= 2.);
+ }
+
+ // dimension until 5 even if simplex tree is of dimension 3 to test the limits
+ for(int dimension = 5; dimension >= 0; dimension --) {
+ std::clog << "### reset_filtration - dimension = " << dimension << "\n";
+ st.reset_filtration(0., dimension);
+ for (auto f_simplex : st.skeleton_simplex_range(3)) {
+ std::clog << "vertex = (";
+ for (auto vertex : st.simplex_vertex_range(f_simplex)) {
+ std::clog << vertex << ",";
+ }
+ std::clog << ") - filtration = " << st.filtration(f_simplex);
+ std::clog << " - dimension = " << st.dimension(f_simplex) << std::endl;
+ if (st.dimension(f_simplex) < dimension)
+ BOOST_CHECK(st.filtration(f_simplex) >= 2.);
+ else
+ BOOST_CHECK(st.filtration(f_simplex) == 0.);
+ }
+ }
+
+}
+
diff --git a/src/python/gudhi/simplex_tree.pxd b/src/python/gudhi/simplex_tree.pxd
index 75e94e0b..3b494ba3 100644
--- a/src/python/gudhi/simplex_tree.pxd
+++ b/src/python/gudhi/simplex_tree.pxd
@@ -58,6 +58,7 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi":
void compute_extended_filtration() nogil
vector[vector[pair[int, pair[double, double]]]] compute_extended_persistence_subdiagrams(vector[pair[int, pair[double, double]]] dgm, double min_persistence) nogil
Simplex_tree_interface_full_featured* collapse_edges(int nb_collapse_iteration) nogil
+ void reset_filtration(double filtration, int dimension) nogil
# Iterators over Simplex tree
pair[vector[int], double] get_simplex_and_filtration(Simplex_tree_simplex_handle f_simplex) nogil
Simplex_tree_simplices_iterator get_simplices_iterator_begin() nogil
diff --git a/src/python/gudhi/simplex_tree.pyx b/src/python/gudhi/simplex_tree.pyx
index dfb1d985..910711a9 100644
--- a/src/python/gudhi/simplex_tree.pyx
+++ b/src/python/gudhi/simplex_tree.pyx
@@ -328,7 +328,7 @@ cdef class SimplexTree:
return self.get_ptr().prune_above_filtration(filtration)
def expansion(self, max_dim):
- """Expands the Simplex_tree containing only its one skeleton
+ """Expands the simplex tree containing only its one skeleton
until dimension max_dim.
The expanded simplicial complex until dimension :math:`d`
@@ -338,7 +338,7 @@ cdef class SimplexTree:
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
+ The simplex tree must contain no simplex of dimension bigger than
1 when calling the method.
:param max_dim: The maximal dimension.
@@ -358,6 +358,20 @@ cdef class SimplexTree:
"""
return self.get_ptr().make_filtration_non_decreasing()
+ def reset_filtration(self, filtration, min_dim = 0):
+ """This function resets the filtration value of all the simplices of dimension at least min_dim. Resets all the
+ simplex tree when `min_dim = 0`.
+ `reset_filtration` may break the filtration property with `min_dim > 0`, and it is the user's responsibility to
+ make it a valid filtration (using a large enough `filt_value`, or calling `make_filtration_non_decreasing`
+ afterwards for instance).
+
+ :param filtration: New threshold value.
+ :type filtration: float.
+ :param min_dim: The minimal dimension. Default value is 0.
+ :type min_dim: int.
+ """
+ self.get_ptr().reset_filtration(filtration, min_dim)
+
def extend_filtration(self):
""" Extend filtration for computing extended persistence. This function only uses the
filtration values at the 0-dimensional simplices, and computes the extended persistence
@@ -366,14 +380,14 @@ cdef class SimplexTree:
.. note::
Note that after calling this function, the filtration
- values are actually modified within the Simplex_tree.
+ values are actually modified within the simplex tree.
The function :func:`extended_persistence`
retrieves the original values.
.. note::
Note that this code creates an extra vertex internally, so you should make sure that
- the Simplex_tree does not contain a vertex with the largest possible value (i.e., 4294967295).
+ the simplex tree does not contain a vertex with the largest possible value (i.e., 4294967295).
"""
self.get_ptr().compute_extended_filtration()
diff --git a/src/python/test/test_simplex_tree.py b/src/python/test/test_simplex_tree.py
index 83be0602..ac2b59c7 100755
--- a/src/python/test/test_simplex_tree.py
+++ b/src/python/test/test_simplex_tree.py
@@ -356,5 +356,27 @@ def test_collapse_edges():
st.collapse_edges()
assert st.num_simplices() == 9
assert st.find([1, 3]) == False
- for simplex in st.get_skeleton(0):
- assert simplex[1] == 1.
+ for simplex in st.get_skeleton(0):
+ assert simplex[1] == 1.
+
+def test_reset_filtration():
+ st = SimplexTree()
+
+ assert st.insert([0, 1, 2], 3.) == True
+ assert st.insert([0, 3], 2.) == True
+ assert st.insert([3, 4, 5], 3.) == True
+ assert st.insert([0, 1, 6, 7], 4.) == True
+
+ # Guaranteed by construction
+ for simplex in st.get_simplices():
+ assert st.filtration(simplex[0]) >= 2.
+
+ # dimension until 5 even if simplex tree is of dimension 3 to test the limits
+ for dimension in range(5, -1, -1):
+ st.reset_filtration(0., dimension)
+ for simplex in st.get_skeleton(3):
+ print(simplex)
+ if len(simplex[0]) < (dimension) + 1:
+ assert st.filtration(simplex[0]) >= 2.
+ else:
+ assert st.filtration(simplex[0]) == 0.