Note
Click here to download the full example code
The plots display firstly what a K-means algorithm would yield using three clusters. It is then shown what the effect of a bad initialization is on the classification process: By setting n_init to only 1 (default is 10), the amount of times that the algorithm will be run with different centroid seeds is reduced. The next plot displays what using eight clusters would deliver and finally the ground truth.
print(__doc__) # Code source: Gaël Varoquaux # Modified for documentation by Jaques Grobler # License: BSD 3 clause import numpy as np import matplotlib.pyplot as plt # Though the following import is not directly being used, it is required # for 3D projection to work from mpl_toolkits.mplot3d import Axes3D from sklearn.cluster import KMeans from sklearn import datasets np.random.seed(5) iris = datasets.load_iris() X = iris.data y = iris.target estimators = [('k_means_iris_8', KMeans(n_clusters=8)), ('k_means_iris_3', KMeans(n_clusters=3)), ('k_means_iris_bad_init', KMeans(n_clusters=3, n_init=1, init='random'))] fignum = 1 titles = ['8 clusters', '3 clusters', '3 clusters, bad initialization'] for name, est in estimators: fig = plt.figure(fignum, figsize=(4, 3)) ax = Axes3D(fig, rect=[0, 0, .95, 1], elev=48, azim=134) est.fit(X) labels = est.labels_ ax.scatter(X[:, 3], X[:, 0], X[:, 2], c=labels.astype(np.float), edgecolor='k') ax.w_xaxis.set_ticklabels([]) ax.w_yaxis.set_ticklabels([]) ax.w_zaxis.set_ticklabels([]) ax.set_xlabel('Petal width') ax.set_ylabel('Sepal length') ax.set_zlabel('Petal length') ax.set_title(titles[fignum - 1]) ax.dist = 12 fignum = fignum + 1 # Plot the ground truth fig = plt.figure(fignum, figsize=(4, 3)) ax = Axes3D(fig, rect=[0, 0, .95, 1], elev=48, azim=134) for name, label in [('Setosa', 0), ('Versicolour', 1), ('Virginica', 2)]: ax.text3D(X[y == label, 3].mean(), X[y == label, 0].mean(), X[y == label, 2].mean() + 2, name, horizontalalignment='center', bbox=dict(alpha=.2, edgecolor='w', facecolor='w')) # Reorder the labels to have colors matching the cluster results y = np.choose(y, [1, 2, 0]).astype(np.float) ax.scatter(X[:, 3], X[:, 0], X[:, 2], c=y, edgecolor='k') ax.w_xaxis.set_ticklabels([]) ax.w_yaxis.set_ticklabels([]) ax.w_zaxis.set_ticklabels([]) ax.set_xlabel('Petal width') ax.set_ylabel('Sepal length') ax.set_zlabel('Petal length') ax.set_title('Ground Truth') ax.dist = 12 fig.show()
Total running time of the script: ( 0 minutes 0.356 seconds)
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http://scikit-learn.org/stable/auto_examples/cluster/plot_cluster_iris.html