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[WIP] ENH Optimal n_clusters values #6948

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81 changes: 81 additions & 0 deletions examples/cluster/plot_optimal_n_clusters.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,81 @@
"""Plot the results of the gap criterium."""

# Authors: Thierry Guillemot <thierry.guillemot.work@gmail.com>

import time
import numpy as np
import matplotlib.pyplot as plt

from sklearn.cluster import KMeans, SpectralClustering, OptimalNClusterSearch
from sklearn.datasets import make_blobs, make_circles, make_moons
from sklearn.metrics import calinski_harabaz_score, fowlkes_mallows_score
from sklearn.metrics import silhouette_score
from sklearn.utils import check_random_state


n_samples, n_features, random_state = 1000, 2, 1
parameters = {'n_clusters': np.arange(1, 8)}

rng = check_random_state(random_state)
datasets = [
('3 clusters', make_blobs(n_samples=n_samples, n_features=2,
random_state=random_state, centers=3)),
('5 clusters', make_blobs(n_samples=n_samples, n_features=2,
random_state=random_state, centers=5)),
('random', (rng.rand(n_samples, n_features),
np.zeros(n_samples, dtype=int))),
('circle', make_circles(n_samples=n_samples, factor=.5, noise=.05,
shuffle=True, random_state=random_state)),
('moon', make_moons(n_samples=n_samples, noise=.05,
shuffle=True, random_state=random_state)),
]

estimator = SpectralClustering(eigen_solver='arpack',
affinity="nearest_neighbors",
n_init=10, random_state=0)
# estimator = KMeans(n_init=10, random_state=0)
searchers = [
# ('Silhouette', OptimalNClusterSearch(
# estimator=estimator, parameters=parameters,
# fitting_process='unsupervised', metric=silhouette_score)),
# ('Calinski', OptimalNClusterSearch(
# estimator=estimator, parameters=parameters,
# fitting_process='unsupervised', metric=calinski_harabaz_score)),
# ('Stability', OptimalNClusterSearch(
# estimator=estimator, parameters=parameters, random_state=0,
# fitting_process='stability', metric=fowlkes_mallows_score)),
# ('Distortion jump', OptimalNClusterSearch(
# estimator=estimator, parameters=parameters,
# fitting_process='distortion_jump')),
# ('Gap', OptimalNClusterSearch(
# estimator=estimator, parameters=parameters, random_state=0,
# fitting_process='gap', metric=silhouette_score)),
('Pham', OptimalNClusterSearch(
estimator=estimator, parameters=parameters, fitting_process='pham',
metric=silhouette_score)),
]

color = 'bgrcmyk'
plt.figure(figsize=(13, 9.5))
plt.subplots_adjust(left=.001, right=.999, bottom=.001, top=.96, wspace=.05,
hspace=.01)
for k, (data_name, data) in enumerate(datasets):
X, _ = data
for l, (search_name, search) in enumerate(searchers):
t0 = time.time()
y = search.fit(X).best_estimator_.labels_
t1 = time.time()

colors = np.array([color[k] for k in y])
plt.subplot(len(datasets), len(searchers),
len(searchers) * k + l + 1)
if k == 0:
plt.title(search_name, size=18)
plt.scatter(X[:, 0], X[:, 1], color=colors, alpha=.6)
plt.xticks(())
plt.yticks(())
plt.axis('equal')
plt.text(.99, .01, ('%.2fs' % (t1 - t0)).lstrip('0'),
transform=plt.gca().transAxes, size=15,
horizontalalignment='right')
plt.show()
4 changes: 3 additions & 1 deletion sklearn/cluster/__init__.py
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@
from .dbscan_ import dbscan, DBSCAN
from .bicluster import SpectralBiclustering, SpectralCoclustering
from .birch import Birch
from .optimal_nclusters_search import OptimalNClusterSearch

__all__ = ['AffinityPropagation',
'AgglomerativeClustering',
Expand All @@ -33,4 +34,5 @@
'spectral_clustering',
'ward_tree',
'SpectralBiclustering',
'SpectralCoclustering']
'SpectralCoclustering',
'OptimalNClusterSearch']
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