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Diffstat (limited to 'src/python/example/rips_complex_edge_collapse_example.py')
-rwxr-xr-x | src/python/example/rips_complex_edge_collapse_example.py | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/src/python/example/rips_complex_edge_collapse_example.py b/src/python/example/rips_complex_edge_collapse_example.py new file mode 100755 index 00000000..b26eb9fc --- /dev/null +++ b/src/python/example/rips_complex_edge_collapse_example.py @@ -0,0 +1,62 @@ +#!/usr/bin/env python + +import gudhi +import matplotlib.pyplot as plt +import time + +""" 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 +""" + +__author__ = "Vincent Rouvreau" +__copyright__ = "Copyright (C) 2020 Inria" +__license__ = "MIT" + + +print("#####################################################################") +print("RipsComplex (only the one-skeleton) creation from tore3D_300.off file") + +off_file = gudhi.__root_source_dir__ + '/data/points/tore3D_300.off' +point_cloud = gudhi.read_points_from_off_file(off_file = off_file) +rips_complex = gudhi.RipsComplex(points=point_cloud, max_edge_length=12.0) +simplex_tree = rips_complex.create_simplex_tree(max_dimension=1) +print('1. Rips complex is of dimension ', simplex_tree.dimension(), ' - ', + simplex_tree.num_simplices(), ' simplices - ', + simplex_tree.num_vertices(), ' vertices.') + +# Expansion of this one-skeleton would require a lot of memory. Let's collapse it +start = time.process_time() +simplex_tree.collapse_edges() +print('2. Rips complex is of dimension ', simplex_tree.dimension(), ' - ', + simplex_tree.num_simplices(), ' simplices - ', + simplex_tree.num_vertices(), ' vertices.') +simplex_tree.expansion(3) +diag = simplex_tree.persistence() +print("Collapse, expansion and persistence computation took ", time.process_time() - start, " sec.") + +# Use subplots to display diagram and density side by side +fig, axes = plt.subplots(nrows=1, ncols=2, figsize=(12, 5)) +gudhi.plot_persistence_diagram(diag, axes=axes[0]) +axes[0].set_title("Persistence after 1 collapse") + +# Collapse can be performed several times. Let's collapse it 3 times +start = time.process_time() +simplex_tree.collapse_edges(nb_iterations = 3) +print('3. Rips complex is of dimension ', simplex_tree.dimension(), ' - ', + simplex_tree.num_simplices(), ' simplices - ', + simplex_tree.num_vertices(), ' vertices.') +simplex_tree.expansion(3) +diag = simplex_tree.persistence() +print("Collapse, expansion and persistence computation took ", time.process_time() - start, " sec.") + +gudhi.plot_persistence_diagram(diag, axes=axes[1]) +axes[1].set_title("Persistence after 3 more collapses") + +# Plot the 2 persistence diagrams side to side to check the persistence is the same +plt.show()
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