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Diffstat (limited to 'cython/cython/alpha_complex.pyx')
-rw-r--r-- | cython/cython/alpha_complex.pyx | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/cython/cython/alpha_complex.pyx b/cython/cython/alpha_complex.pyx new file mode 100644 index 00000000..a0e8f9b7 --- /dev/null +++ b/cython/cython/alpha_complex.pyx @@ -0,0 +1,121 @@ +from cython cimport numeric +from libcpp.vector cimport vector +from libcpp.utility cimport pair +from libcpp.string cimport string +from libcpp cimport bool +import os + +"""This file is part of the Gudhi Library. The Gudhi library + (Geometric Understanding in Higher Dimensions) is a generic C++ + library for computational topology. + + Author(s): Vincent Rouvreau + + Copyright (C) 2016 INRIA + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +""" + +__author__ = "Vincent Rouvreau" +__copyright__ = "Copyright (C) 2016 INRIA" +__license__ = "GPL v3" + +cdef extern from "Alpha_complex_interface.h" namespace "Gudhi": + cdef cppclass Alpha_complex_interface "Gudhi::alpha_complex::Alpha_complex_interface": + Alpha_complex_interface(vector[vector[double]] points) + # bool from_file is a workaround for cython to find the correct signature + Alpha_complex_interface(string off_file, bool from_file) + vector[double] get_point(int vertex) + void create_simplex_tree(Simplex_tree_interface_full_featured* simplex_tree, double max_alpha_square) + +# AlphaComplex python interface +cdef class AlphaComplex: + """AlphaComplex is a simplicial complex constructed from the finite cells + of a Delaunay Triangulation. + + The filtration value of each simplex is computed as the square of the + circumradius of the simplex if the circumsphere is empty (the simplex is + then said to be Gabriel), and as the minimum of the filtration values of + the codimension 1 cofaces that make it not Gabriel otherwise. + + All simplices that have a filtration value strictly greater than a given + alpha squared value are not inserted into the complex. + + .. note:: + + When Alpha_complex is constructed with an infinite value of alpha, the + complex is a Delaunay complex. + + """ + + cdef Alpha_complex_interface * thisptr + + # Fake constructor that does nothing but documenting the constructor + def __init__(self, points=None, off_file=''): + """AlphaComplex constructor. + + :param points: A list of points in d-Dimension. + :type points: list of list of double + + Or + + :param off_file: An OFF file style name. + :type off_file: string + """ + + # The real cython constructor + def __cinit__(self, points=None, off_file=''): + if off_file is not '': + if os.path.isfile(off_file): + self.thisptr = new Alpha_complex_interface(str.encode(off_file), True) + else: + print("file " + off_file + " not found.") + else: + if points is None: + # Empty Alpha construction + points=[] + self.thisptr = new Alpha_complex_interface(points) + + + def __dealloc__(self): + if self.thisptr != NULL: + del self.thisptr + + def __is_defined(self): + """Returns true if AlphaComplex pointer is not NULL. + """ + return self.thisptr != NULL + + def get_point(self, vertex): + """This function returns the point corresponding to a given vertex. + + :param vertex: The vertex. + :type vertex: int + :rtype: list of float + :returns: the point. + """ + cdef vector[double] point = self.thisptr.get_point(vertex) + return point + + def create_simplex_tree(self, max_alpha_square=float('inf')): + """ + :param max_alpha_square: The maximum alpha square threshold the + simplices shall not exceed. Default is set to infinity. + :type max_alpha_square: float + :returns: A simplex tree created from the Delaunay Triangulation. + :rtype: SimplexTree + """ + simplex_tree = SimplexTree() + self.thisptr.create_simplex_tree(simplex_tree.thisptr, max_alpha_square) + return simplex_tree |