diff options
Diffstat (limited to 'src/python/gudhi/cubical_complex.pyx')
| -rw-r--r-- | src/python/gudhi/cubical_complex.pyx | 133 |
1 files changed, 101 insertions, 32 deletions
diff --git a/src/python/gudhi/cubical_complex.pyx b/src/python/gudhi/cubical_complex.pyx index cbeda014..ca979eda 100644 --- a/src/python/gudhi/cubical_complex.pyx +++ b/src/python/gudhi/cubical_complex.pyx @@ -1,5 +1,7 @@ -# This file is part of the Gudhi Library - https://gudhi.inria.fr/ - which is released under MIT. -# See file LICENSE or go to https://gudhi.inria.fr/licensing/ for full license details. +# This file is part of the Gudhi Library - https://gudhi.inria.fr/ - +# which is released under MIT. +# See file LICENSE or go to https://gudhi.inria.fr/licensing/ for full +# license details. # Author(s): Vincent Rouvreau # # Copyright (C) 2016 Inria @@ -7,12 +9,15 @@ # Modification(s): # - YYYY/MM Author: Description of the modification +from __future__ import print_function from cython cimport numeric from libcpp.vector cimport vector from libcpp.utility cimport pair from libcpp.string cimport string from libcpp cimport bool +import errno import os +import sys import numpy as np @@ -30,7 +35,9 @@ cdef extern from "Cubical_complex_interface.h" namespace "Gudhi": cdef extern from "Persistent_cohomology_interface.h" namespace "Gudhi": cdef cppclass Cubical_complex_persistence_interface "Gudhi::Persistent_cohomology_interface<Gudhi::Cubical_complex::Cubical_complex_interface<>>": Cubical_complex_persistence_interface(Bitmap_cubical_complex_base_interface * st, bool persistence_dim_max) - vector[pair[int, pair[double, double]]] get_persistence(int homology_coeff_field, double min_persistence) + void compute_persistence(int homology_coeff_field, double min_persistence) + vector[pair[int, pair[double, double]]] get_persistence() + vector[vector[int]] cofaces_of_cubical_persistence_pairs() vector[int] betti_numbers() vector[int] persistent_betti_numbers(double from_value, double to_value) vector[pair[double,double]] intervals_in_dimension(int dimension) @@ -87,10 +94,12 @@ cdef class CubicalComplex: if os.path.isfile(perseus_file): self.thisptr = new Bitmap_cubical_complex_base_interface(perseus_file.encode('utf-8')) else: - print("file " + perseus_file + " not found.") + raise FileNotFoundError(errno.ENOENT, os.strerror(errno.ENOENT), + perseus_file) else: print("CubicalComplex can be constructed from dimensions and " - "top_dimensional_cells or from a Perseus-style file name.") + "top_dimensional_cells or from a Perseus-style file name.", + file=sys.stderr) def __dealloc__(self): if self.thisptr != NULL: @@ -122,8 +131,31 @@ cdef class CubicalComplex: """ return self.thisptr.dimension() + def compute_persistence(self, homology_coeff_field=11, min_persistence=0): + """This function computes the persistence of the complex, so it can be + accessed through :func:`persistent_betti_numbers`, + :func:`persistence_intervals_in_dimension`, etc. This function is + equivalent to :func:`persistence` when you do not want the list + :func:`persistence` returns. + + :param homology_coeff_field: The homology coefficient field. Must be a + prime number + :type homology_coeff_field: int. + :param min_persistence: The minimum persistence value 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: Nothing. + """ + if self.pcohptr != NULL: + del self.pcohptr + assert self.__is_defined() + self.pcohptr = new Cubical_complex_persistence_interface(self.thisptr, True) + self.pcohptr.compute_persistence(homology_coeff_field, min_persistence) + def persistence(self, homology_coeff_field=11, min_persistence=0): - """This function returns the persistence of the complex. + """This function computes and returns the persistence of the complex. :param homology_coeff_field: The homology coefficient field. Must be a prime number @@ -136,30 +168,74 @@ cdef class CubicalComplex: :returns: list of pairs(dimension, pair(birth, death)) -- the persistence of the complex. """ - if self.pcohptr != NULL: - del self.pcohptr - if self.thisptr != NULL: - self.pcohptr = new Cubical_complex_persistence_interface(self.thisptr, True) - cdef vector[pair[int, pair[double, double]]] persistence_result - if self.pcohptr != NULL: - persistence_result = self.pcohptr.get_persistence(homology_coeff_field, min_persistence) - return persistence_result + self.compute_persistence(homology_coeff_field, min_persistence) + return self.pcohptr.get_persistence() + + def cofaces_of_persistence_pairs(self): + """A persistence interval is described by a pair of cells, one that creates the + feature and one that kills it. The filtration values of those 2 cells give coordinates + for a point in a persistence diagram, or a bar in a barcode. Structurally, in the + cubical complexes provided here, the filtration value of any cell is the minimum of the + filtration values of the maximal cells that contain it. Connecting persistence diagram + coordinates to the corresponding value in the input (i.e. the filtration values of + the top-dimensional cells) is useful for differentiation purposes. + + This function returns a list of pairs of top-dimensional cells corresponding to + the persistence birth and death cells of the filtration. The cells are represented by + their indices in the input list of top-dimensional cells (and not their indices in the + internal datastructure that includes non-maximal cells). Note that when two adjacent + top-dimensional cells have the same filtration value, we arbitrarily return one of the two + when calling the function on one of their common faces. + + :returns: The top-dimensional cells/cofaces of the positive and negative cells, + together with the corresponding homological dimension, in two lists of numpy arrays of integers. + The first list contains the regular persistence pairs, grouped by dimension. + It contains numpy arrays of shape [number_of_persistence_points, 2]. + The indices of the arrays in the list correspond to the homological dimensions, and the + integers of each row in each array correspond to: (index of positive top-dimensional cell, + index of negative top-dimensional cell). + The second list contains the essential features, grouped by dimension. + It contains numpy arrays of shape [number_of_persistence_points, 1]. + The indices of the arrays in the list correspond to the homological dimensions, and the + integers of each row in each array correspond to: (index of positive top-dimensional cell). + """ + + assert self.pcohptr != NULL, "compute_persistence() must be called before cofaces_of_persistence_pairs()" + + cdef vector[vector[int]] persistence_result + output = [[],[]] + persistence_result = self.pcohptr.cofaces_of_cubical_persistence_pairs() + pr = np.array(persistence_result) + + ess_ind = np.argwhere(pr[:,2] == -1)[:,0] + ess = pr[ess_ind] + max_h = max(ess[:,0])+1 + for h in range(max_h): + hidxs = np.argwhere(ess[:,0] == h)[:,0] + output[1].append(ess[hidxs][:,1]) + + reg_ind = np.setdiff1d(np.array(range(len(pr))), ess_ind) + reg = pr[reg_ind] + max_h = max(reg[:,0])+1 + for h in range(max_h): + hidxs = np.argwhere(reg[:,0] == h)[:,0] + output[0].append(reg[hidxs][:,1:]) + + return output def betti_numbers(self): """This function returns the Betti numbers of the complex. :returns: list of int -- The Betti numbers ([B0, B1, ..., Bn]). - :note: betti_numbers function requires persistence function to be + :note: betti_numbers function requires :func:`compute_persistence` function to be launched first. :note: betti_numbers function always returns [1, 0, 0, ...] as infinity filtration cubes are not removed from the complex. """ - cdef vector[int] bn_result - if self.pcohptr != NULL: - bn_result = self.pcohptr.betti_numbers() - return bn_result + assert self.pcohptr != NULL, "compute_persistence() must be called before betti_numbers()" + return self.pcohptr.betti_numbers() def persistent_betti_numbers(self, from_value, to_value): """This function returns the persistent Betti numbers of the complex. @@ -174,13 +250,11 @@ cdef class CubicalComplex: :returns: list of int -- The persistent Betti numbers ([B0, B1, ..., Bn]). - :note: persistent_betti_numbers function requires persistence + :note: persistent_betti_numbers function requires :func:`compute_persistence` function to be launched first. """ - cdef vector[int] pbn_result - if self.pcohptr != NULL: - pbn_result = self.pcohptr.persistent_betti_numbers(<double>from_value, <double>to_value) - return pbn_result + assert self.pcohptr != NULL, "compute_persistence() must be called before persistent_betti_numbers()" + return self.pcohptr.persistent_betti_numbers(<double>from_value, <double>to_value) def persistence_intervals_in_dimension(self, dimension): """This function returns the persistence intervals of the complex in a @@ -191,13 +265,8 @@ cdef class CubicalComplex: :returns: The persistence intervals. :rtype: numpy array of dimension 2 - :note: intervals_in_dim function requires persistence function to be + :note: intervals_in_dim function requires :func:`compute_persistence` function to be launched first. """ - cdef vector[pair[double,double]] intervals_result - if self.pcohptr != NULL: - intervals_result = self.pcohptr.intervals_in_dimension(dimension) - else: - print("intervals_in_dim function requires persistence function" - " to be launched first.") - return np.array(intervals_result) + assert self.pcohptr != NULL, "compute_persistence() must be called before persistence_intervals_in_dimension()" + return np.array(self.pcohptr.intervals_in_dimension(dimension)) |