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""" 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
Modification(s):
- YYYY/MM Author: Description of the modification
"""
from gudhi import AlphaComplex, SimplexTree
import math
import numpy as np
import pytest
try:
# python3
from itertools import zip_longest
except ImportError:
# python2
from itertools import izip_longest as zip_longest
__author__ = "Vincent Rouvreau"
__copyright__ = "Copyright (C) 2016 Inria"
__license__ = "MIT"
def test_empty_alpha():
alpha_complex = AlphaComplex(points=[[0, 0]])
assert alpha_complex.__is_defined() == True
def test_infinite_alpha():
point_list = [[0, 0], [1, 0], [0, 1], [1, 1]]
alpha_complex = AlphaComplex(points=point_list)
assert alpha_complex.__is_defined() == True
simplex_tree = alpha_complex.create_simplex_tree()
assert simplex_tree.__is_persistence_defined() == False
assert simplex_tree.num_simplices() == 11
assert simplex_tree.num_vertices() == 4
assert list(simplex_tree.get_filtration()) == [
([0], 0.0),
([1], 0.0),
([2], 0.0),
([3], 0.0),
([0, 1], 0.25),
([0, 2], 0.25),
([1, 3], 0.25),
([2, 3], 0.25),
([1, 2], 0.5),
([0, 1, 2], 0.5),
([1, 2, 3], 0.5),
]
assert simplex_tree.get_star([0]) == [
([0], 0.0),
([0, 1], 0.25),
([0, 1, 2], 0.5),
([0, 2], 0.25),
]
assert simplex_tree.get_cofaces([0], 1) == [([0, 1], 0.25), ([0, 2], 0.25)]
assert point_list[0] == alpha_complex.get_point(0)
assert point_list[1] == alpha_complex.get_point(1)
assert point_list[2] == alpha_complex.get_point(2)
assert point_list[3] == alpha_complex.get_point(3)
try:
alpha_complex.get_point(4) == []
except IndexError:
pass
else:
assert False
try:
alpha_complex.get_point(125) == []
except IndexError:
pass
else:
assert False
def test_filtered_alpha():
point_list = [[0, 0], [1, 0], [0, 1], [1, 1]]
filtered_alpha = AlphaComplex(points=point_list)
simplex_tree = filtered_alpha.create_simplex_tree(max_alpha_square=0.25)
assert simplex_tree.num_simplices() == 8
assert simplex_tree.num_vertices() == 4
assert point_list[0] == filtered_alpha.get_point(0)
assert point_list[1] == filtered_alpha.get_point(1)
assert point_list[2] == filtered_alpha.get_point(2)
assert point_list[3] == filtered_alpha.get_point(3)
try:
filtered_alpha.get_point(4) == []
except IndexError:
pass
else:
assert False
try:
filtered_alpha.get_point(125) == []
except IndexError:
pass
else:
assert False
assert list(simplex_tree.get_filtration()) == [
([0], 0.0),
([1], 0.0),
([2], 0.0),
([3], 0.0),
([0, 1], 0.25),
([0, 2], 0.25),
([1, 3], 0.25),
([2, 3], 0.25),
]
assert simplex_tree.get_star([0]) == [([0], 0.0), ([0, 1], 0.25), ([0, 2], 0.25)]
assert simplex_tree.get_cofaces([0], 1) == [([0, 1], 0.25), ([0, 2], 0.25)]
def test_safe_alpha_persistence_comparison():
#generate periodic signal
time = np.arange(0, 10, 1)
signal = [math.sin(x) for x in time]
delta = math.pi
delayed = [math.sin(x + delta) for x in time]
#construct embedding
embedding1 = [[signal[i], -signal[i]] for i in range(len(time))]
embedding2 = [[signal[i], delayed[i]] for i in range(len(time))]
#build alpha complex and simplex tree
alpha_complex1 = AlphaComplex(points=embedding1)
simplex_tree1 = alpha_complex1.create_simplex_tree()
alpha_complex2 = AlphaComplex(points=embedding2)
simplex_tree2 = alpha_complex2.create_simplex_tree()
diag1 = simplex_tree1.persistence()
diag2 = simplex_tree2.persistence()
for (first_p, second_p) in zip_longest(diag1, diag2):
assert first_p[0] == pytest.approx(second_p[0])
assert first_p[1] == pytest.approx(second_p[1])
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