diff options
Diffstat (limited to 'src/python')
-rw-r--r-- | src/python/gudhi/simplex_tree.pxd | 2 | ||||
-rw-r--r-- | src/python/gudhi/simplex_tree.pyx | 51 | ||||
-rw-r--r-- | src/python/include/Simplex_tree_interface.h | 40 | ||||
-rwxr-xr-x | src/python/test/test_simplex_tree.py | 82 |
4 files changed, 175 insertions, 0 deletions
diff --git a/src/python/gudhi/simplex_tree.pxd b/src/python/gudhi/simplex_tree.pxd index 82f155de..595f22bb 100644 --- a/src/python/gudhi/simplex_tree.pxd +++ b/src/python/gudhi/simplex_tree.pxd @@ -57,6 +57,8 @@ cdef extern from "Simplex_tree_interface.h" namespace "Gudhi": void remove_maximal_simplex(vector[int] simplex) bool prune_above_filtration(double filtration) bool make_filtration_non_decreasing() + void compute_extended_filtration() + vector[vector[pair[int, pair[double, double]]]] compute_extended_persistence_subdiagrams(vector[pair[int, pair[double, double]]] dgm, double min_persistence) # Iterators over Simplex tree pair[vector[int], double] get_simplex_and_filtration(Simplex_tree_simplex_handle f_simplex) Simplex_tree_simplices_iterator get_simplices_iterator_begin() diff --git a/src/python/gudhi/simplex_tree.pyx b/src/python/gudhi/simplex_tree.pyx index c01cc905..cc3753e1 100644 --- a/src/python/gudhi/simplex_tree.pyx +++ b/src/python/gudhi/simplex_tree.pyx @@ -396,6 +396,57 @@ cdef class SimplexTree: """ return self.get_ptr().make_filtration_non_decreasing() + 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 + diagram induced by the lower-star filtration computed with these values. + + .. note:: + + Note that after calling this function, the filtration + values are actually modified within the Simplex_tree. + The function :func:`extended_persistence()<gudhi.SimplexTree.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). + """ + return self.get_ptr().compute_extended_filtration() + + def extended_persistence(self, homology_coeff_field=11, min_persistence=0): + """This function retrieves good values for extended persistence, and separate the diagrams + into the Ordinary, Relative, Extended+ and Extended- subdiagrams. + + :param homology_coeff_field: The homology coefficient field. Must be a + prime number. Default value is 11. + :type homology_coeff_field: int. + :param min_persistence: The minimum persistence value (i.e., the absolute value of the difference between the persistence diagram point coordinates) to take into + account (strictly greater than min_persistence). Default value is + 0.0. + Sets min_persistence to -1.0 to see all values. + :type min_persistence: float. + :returns: A list of four persistence diagrams in the format described in :func:`persistence()<gudhi.SimplexTree.persistence>`. The first one is Ordinary, the second one is Relative, the third one is Extended+ and the fourth one is Extended-. See https://link.springer.com/article/10.1007/s10208-008-9027-z and/or section 2.2 in https://link.springer.com/article/10.1007/s10208-017-9370-z for a description of these subtypes. + + .. note:: + + This function should be called only if :func:`extend_filtration()<gudhi.SimplexTree.extend_filtration>` has been called first! + + .. note:: + + The coordinates of the persistence diagram points might be a little different than the + original filtration values due to the internal transformation (scaling to [-2,-1]) that is + performed on these values during the computation of extended persistence. + """ + cdef vector[pair[int, pair[double, double]]] persistence_result + if self.pcohptr != NULL: + del self.pcohptr + self.pcohptr = new Simplex_tree_persistence_interface(self.get_ptr(), False) + persistence_result = self.pcohptr.get_persistence(homology_coeff_field, -1.) + return self.get_ptr().compute_extended_persistence_subdiagrams(persistence_result, min_persistence) + + def persistence(self, homology_coeff_field=11, min_persistence=0, persistence_dim_max = False): """This function returns the persistence of the simplicial complex. diff --git a/src/python/include/Simplex_tree_interface.h b/src/python/include/Simplex_tree_interface.h index 4a7062d6..1a18aed6 100644 --- a/src/python/include/Simplex_tree_interface.h +++ b/src/python/include/Simplex_tree_interface.h @@ -37,8 +37,12 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> { using Filtered_simplices = std::vector<Simplex_and_filtration>; using Skeleton_simplex_iterator = typename Base::Skeleton_simplex_iterator; using Complex_simplex_iterator = typename Base::Complex_simplex_iterator; + using Extended_filtration_data = typename Base::Extended_filtration_data; public: + + Extended_filtration_data efd; + bool find_simplex(const Simplex& vh) { return (Base::find(vh) != Base::null_simplex()); } @@ -117,6 +121,42 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> { return cofaces; } + void compute_extended_filtration() { + this->efd = this->extend_filtration(); + this->initialize_filtration(); + return; + } + + std::vector<std::vector<std::pair<int, std::pair<Filtration_value, Filtration_value>>>> compute_extended_persistence_subdiagrams(const std::vector<std::pair<int, std::pair<Filtration_value, Filtration_value>>>& dgm, Filtration_value min_persistence){ + std::vector<std::vector<std::pair<int, std::pair<Filtration_value, Filtration_value>>>> new_dgm(4); + for (unsigned int i = 0; i < dgm.size(); i++){ + std::pair<Filtration_value, Extended_simplex_type> px = this->decode_extended_filtration(dgm[i].second.first, this->efd); + std::pair<Filtration_value, Extended_simplex_type> py = this->decode_extended_filtration(dgm[i].second.second, this->efd); + std::pair<int, std::pair<Filtration_value, Filtration_value>> pd_point = std::make_pair(dgm[i].first, std::make_pair(px.first, py.first)); + if(std::abs(px.first - py.first) > min_persistence){ + //Ordinary + if (px.second == Extended_simplex_type::UP && py.second == Extended_simplex_type::UP){ + new_dgm[0].push_back(pd_point); + } + // Relative + else if (px.second == Extended_simplex_type::DOWN && py.second == Extended_simplex_type::DOWN){ + new_dgm[1].push_back(pd_point); + } + else{ + // Extended+ + if (px.first < py.first){ + new_dgm[2].push_back(pd_point); + } + //Extended- + else{ + new_dgm[3].push_back(pd_point); + } + } + } + } + return new_dgm; + } + 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/test/test_simplex_tree.py b/src/python/test/test_simplex_tree.py index f7848379..70b26e97 100755 --- a/src/python/test/test_simplex_tree.py +++ b/src/python/test/test_simplex_tree.py @@ -9,6 +9,7 @@ """ from gudhi import SimplexTree +import pytest __author__ = "Vincent Rouvreau" __copyright__ = "Copyright (C) 2016 Inria" @@ -250,6 +251,87 @@ def test_make_filtration_non_decreasing(): 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 list(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 list(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) + ] + + dgms = st.extended_persistence(min_persistence=-1.) + + assert dgms[0][0][1][0] == pytest.approx(2.) + assert dgms[0][0][1][1] == pytest.approx(3.) + assert dgms[1][0][1][0] == pytest.approx(5.) + assert dgms[1][0][1][1] == pytest.approx(4.) + assert dgms[2][0][1][0] == pytest.approx(1.) + assert dgms[2][0][1][1] == pytest.approx(6.) + assert dgms[3][0][1][0] == pytest.approx(6.) + assert dgms[3][0][1][1] == pytest.approx(1.) + def test_simplices_iterator(): st = SimplexTree() |