This example applies to The Olivetti faces dataset different unsupervised matrix decomposition (dimension reduction) methods from the module sklearn.decomposition
(see the documentation chapter Decomposing signals in components (matrix factorization problems)) .
print(__doc__) # Authors: Vlad Niculae, Alexandre Gramfort # License: BSD 3 clause import logging from time import time from numpy.random import RandomState import matplotlib.pyplot as plt from sklearn.datasets import fetch_olivetti_faces from sklearn.cluster import MiniBatchKMeans from sklearn import decomposition # Display progress logs on stdout logging.basicConfig(level=logging.INFO, format='%(asctime)s %(levelname)s %(message)s') n_row, n_col = 2, 3 n_components = n_row * n_col image_shape = (64, 64) rng = RandomState(0)
Load faces data
dataset = fetch_olivetti_faces(shuffle=True, random_state=rng) faces = dataset.data n_samples, n_features = faces.shape # global centering faces_centered = faces - faces.mean(axis=0) # local centering faces_centered -= faces_centered.mean(axis=1).reshape(n_samples, -1) print("Dataset consists of %d faces" % n_samples)
Out:
Dataset consists of 400 faces
def plot_gallery(title, images, n_col=n_col, n_row=n_row): plt.figure(figsize=(2. * n_col, 2.26 * n_row)) plt.suptitle(title, size=16) for i, comp in enumerate(images): plt.subplot(n_row, n_col, i + 1) vmax = max(comp.max(), -comp.min()) plt.imshow(comp.reshape(image_shape), cmap=plt.cm.gray, interpolation='nearest', vmin=-vmax, vmax=vmax) plt.xticks(()) plt.yticks(()) plt.subplots_adjust(0.01, 0.05, 0.99, 0.93, 0.04, 0.)
List of the different estimators, whether to center and transpose the problem, and whether the transformer uses the clustering API.
estimators = [ ('Eigenfaces - PCA using randomized SVD', decomposition.PCA(n_components=n_components, svd_solver='randomized', whiten=True), True), ('Non-negative components - NMF', decomposition.NMF(n_components=n_components, init='nndsvda', tol=5e-3), False), ('Independent components - FastICA', decomposition.FastICA(n_components=n_components, whiten=True), True), ('Sparse comp. - MiniBatchSparsePCA', decomposition.MiniBatchSparsePCA(n_components=n_components, alpha=0.8, n_iter=100, batch_size=3, random_state=rng), True), ('MiniBatchDictionaryLearning', decomposition.MiniBatchDictionaryLearning(n_components=15, alpha=0.1, n_iter=50, batch_size=3, random_state=rng), True), ('Cluster centers - MiniBatchKMeans', MiniBatchKMeans(n_clusters=n_components, tol=1e-3, batch_size=20, max_iter=50, random_state=rng), True), ('Factor Analysis components - FA', decomposition.FactorAnalysis(n_components=n_components, max_iter=2), True), ]
Plot a sample of the input data
plot_gallery("First centered Olivetti faces", faces_centered[:n_components])
Do the estimation and plot it
for name, estimator, center in estimators: print("Extracting the top %d %s..." % (n_components, name)) t0 = time() data = faces if center: data = faces_centered estimator.fit(data) train_time = (time() - t0) print("done in %0.3fs" % train_time) if hasattr(estimator, 'cluster_centers_'): components_ = estimator.cluster_centers_ else: components_ = estimator.components_ if (hasattr(estimator, 'noise_variance_') and estimator.noise_variance_.shape != ()): plot_gallery("Pixelwise variance", estimator.noise_variance_.reshape(1, -1), n_col=1, n_row=1) plot_gallery('%s - Train time %.1fs' % (name, train_time), components_[:n_components]) plt.show()
Out:
Extracting the top 6 Eigenfaces - PCA using randomized SVD... done in 0.090s Extracting the top 6 Non-negative components - NMF... done in 0.675s Extracting the top 6 Independent components - FastICA... done in 0.243s Extracting the top 6 Sparse comp. - MiniBatchSparsePCA... done in 1.103s Extracting the top 6 MiniBatchDictionaryLearning... done in 0.937s Extracting the top 6 Cluster centers - MiniBatchKMeans... done in 0.093s Extracting the top 6 Factor Analysis components - FA... done in 0.105s
Total running time of the script: (0 minutes 6.549 seconds)
Download Python source code:
plot_faces_decomposition.py
Download IPython notebook:
plot_faces_decomposition.ipynb
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