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| 1 | +# -*- coding: utf-8 -*- |
| 2 | +""" |
| 3 | +========================== |
| 4 | +Partial Wasserstein and Gromov-Wasserstein example |
| 5 | +========================== |
| 6 | +
|
| 7 | +This example is designed to show how to use the Partial (Gromov-)Wassertsein |
| 8 | +distance computation in POT. |
| 9 | +""" |
| 10 | + |
| 11 | +# Author: Laetitia Chapel <laetitia.chapel@irisa.fr> |
| 12 | +# License: MIT License |
| 13 | + |
| 14 | +import scipy as sp |
| 15 | +import numpy as np |
| 16 | +import matplotlib.pylab as pl |
| 17 | +import ot |
| 18 | + |
| 19 | + |
| 20 | +############################################################################# |
| 21 | +# |
| 22 | +# Sample two 2D Gaussian distributions and plot them |
| 23 | +# -------------------------------------------------- |
| 24 | +# |
| 25 | +# For demonstration purpose, we sample two Gaussian distributions in 2-d |
| 26 | +# spaces and add some random noise. |
| 27 | + |
| 28 | + |
| 29 | +n_samples = 20 # nb samples (gaussian) |
| 30 | +n_noise = 20 # nb of samples (noise) |
| 31 | + |
| 32 | +mu = np.array([0, 0]) |
| 33 | +cov = np.array([[1, 0], [0, 2]]) |
| 34 | + |
| 35 | +xs = ot.datasets.make_2D_samples_gauss(n_samples, mu, cov) |
| 36 | +xs = np.append(xs, (np.random.rand(n_noise, 2)+1)*4).reshape((-1, 2)) |
| 37 | +xt = ot.datasets.make_2D_samples_gauss(n_samples, mu, cov) |
| 38 | +xt = np.append(xt, (np.random.rand(n_noise, 2)+1)*-3).reshape((-1, 2)) |
| 39 | + |
| 40 | +M = sp.spatial.distance.cdist(xs, xt) |
| 41 | + |
| 42 | +fig = pl.figure() |
| 43 | +ax1 = fig.add_subplot(131) |
| 44 | +ax1.plot(xs[:, 0], xs[:, 1], '+b', label='Source samples') |
| 45 | +ax2 = fig.add_subplot(132) |
| 46 | +ax2.scatter(xt[:, 0], xt[:, 1], color='r') |
| 47 | +ax3 = fig.add_subplot(133) |
| 48 | +ax3.imshow(M) |
| 49 | +pl.show() |
| 50 | + |
| 51 | +############################################################################# |
| 52 | +# |
| 53 | +# Compute partial Wasserstein plans and distance, |
| 54 | +# by transporting 50% of the mass |
| 55 | +# ---------------------------------------------- |
| 56 | + |
| 57 | +p = ot.unif(n_samples + n_noise) |
| 58 | +q = ot.unif(n_samples + n_noise) |
| 59 | + |
| 60 | +w0, log0 = ot.partial.partial_wasserstein(p, q, M, m=0.5, log=True) |
| 61 | +w, log = ot.partial.entropic_partial_wasserstein(p, q, M, reg=0.1, m=0.5, |
| 62 | + log=True) |
| 63 | + |
| 64 | +print('Partial Wasserstein distance (m = 0.5): ' + str(log0['partial_w_dist'])) |
| 65 | +print('Entropic partial Wasserstein distance (m = 0.5): ' + \ |
| 66 | + str(log['partial_w_dist'])) |
| 67 | + |
| 68 | +pl.figure(1, (10, 5)) |
| 69 | +pl.subplot(1, 2, 1) |
| 70 | +pl.imshow(w0, cmap='jet') |
| 71 | +pl.title('Partial Wasserstein') |
| 72 | +pl.subplot(1, 2, 2) |
| 73 | +pl.imshow(w, cmap='jet') |
| 74 | +pl.title('Entropic partial Wasserstein') |
| 75 | +pl.show() |
| 76 | + |
| 77 | + |
| 78 | +############################################################################# |
| 79 | +# |
| 80 | +# Sample one 2D and 3D Gaussian distributions and plot them |
| 81 | +# --------------------------------------------------------- |
| 82 | +# |
| 83 | +# The Gromov-Wasserstein distance allows to compute distances with samples that |
| 84 | +# do not belong to the same metric space. For demonstration purpose, we sample |
| 85 | +# two Gaussian distributions in 2- and 3-dimensional spaces. |
| 86 | + |
| 87 | +n_samples = 20 # nb samples |
| 88 | +n_noise = 10 # nb of samples (noise) |
| 89 | + |
| 90 | +p = ot.unif(n_samples + n_noise) |
| 91 | +q = ot.unif(n_samples + n_noise) |
| 92 | + |
| 93 | +mu_s = np.array([0, 0]) |
| 94 | +cov_s = np.array([[1, 0], [0, 1]]) |
| 95 | + |
| 96 | +mu_t = np.array([0, 0, 0]) |
| 97 | +cov_t = np.array([[1, 0, 0], [0, 1, 0], [0, 0, 1]]) |
| 98 | + |
| 99 | + |
| 100 | +xs = ot.datasets.make_2D_samples_gauss(n_samples, mu_s, cov_s) |
| 101 | +xs = np.concatenate((xs, ((np.random.rand(n_noise, 2)+1)*4)), axis=0) |
| 102 | +P = sp.linalg.sqrtm(cov_t) |
| 103 | +xt = np.random.randn(n_samples, 3).dot(P) + mu_t |
| 104 | +xt = np.concatenate((xt, ((np.random.rand(n_noise, 3)+1)*10)), axis=0) |
| 105 | + |
| 106 | +fig = pl.figure() |
| 107 | +ax1 = fig.add_subplot(121) |
| 108 | +ax1.plot(xs[:, 0], xs[:, 1], '+b', label='Source samples') |
| 109 | +ax2 = fig.add_subplot(122, projection='3d') |
| 110 | +ax2.scatter(xt[:, 0], xt[:, 1], xt[:, 2], color='r') |
| 111 | +pl.show() |
| 112 | + |
| 113 | + |
| 114 | +############################################################################# |
| 115 | +# |
| 116 | +# Compute partial Gromov-Wasserstein plans and distance, |
| 117 | +# by transporting 100% and 2/3 of the mass |
| 118 | +# ----------------------------------------------------- |
| 119 | + |
| 120 | +C1 = sp.spatial.distance.cdist(xs, xs) |
| 121 | +C2 = sp.spatial.distance.cdist(xt, xt) |
| 122 | + |
| 123 | +print('-----m = 1') |
| 124 | +m = 1 |
| 125 | +res0, log0 = ot.partial.partial_gromov_wasserstein(C1, C2, p, q, m=m, |
| 126 | + log=True) |
| 127 | +res, log = ot.partial.entropic_partial_gromov_wasserstein(C1, C2, p, q, 10, |
| 128 | + m=m, log=True) |
| 129 | + |
| 130 | +print('Partial Wasserstein distance (m = 1): ' + str(log0['partial_gw_dist'])) |
| 131 | +print('Entropic partial Wasserstein distance (m = 1): ' + \ |
| 132 | + str(log['partial_gw_dist'])) |
| 133 | + |
| 134 | +pl.figure(1, (10, 5)) |
| 135 | +pl.title("mass to be transported m = 1") |
| 136 | +pl.subplot(1, 2, 1) |
| 137 | +pl.imshow(res0, cmap='jet') |
| 138 | +pl.title('Partial Wasserstein') |
| 139 | +pl.subplot(1, 2, 2) |
| 140 | +pl.imshow(res, cmap='jet') |
| 141 | +pl.title('Entropic partial Wasserstein') |
| 142 | +pl.show() |
| 143 | + |
| 144 | +print('-----m = 2/3') |
| 145 | +m = 2/3 |
| 146 | +res0, log0 = ot.partial.partial_gromov_wasserstein(C1, C2, p, q, m=m, log=True) |
| 147 | +res, log = ot.partial.entropic_partial_gromov_wasserstein(C1, C2, p, q, 10, |
| 148 | + m=m, log=True) |
| 149 | + |
| 150 | +print('Partial Wasserstein distance (m = 2/3): ' + \ |
| 151 | + str(log0['partial_gw_dist'])) |
| 152 | +print('Entropic partial Wasserstein distance (m = 2/3): ' + \ |
| 153 | + str(log['partial_gw_dist'])) |
| 154 | + |
| 155 | +pl.figure(1, (10, 5)) |
| 156 | +pl.title("mass to be transported m = 2/3") |
| 157 | +pl.subplot(1, 2, 1) |
| 158 | +pl.imshow(res0, cmap='jet') |
| 159 | +pl.title('Partial Wasserstein') |
| 160 | +pl.subplot(1, 2, 2) |
| 161 | +pl.imshow(res, cmap='jet') |
| 162 | +pl.title('Entropic partial Wasserstein') |
| 163 | +pl.show() |
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