.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "auto_examples/ensemble/plot_random_forest_embedding.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. note:: :class: sphx-glr-download-link-note :ref:`Go to the end ` to download the full example code or to run this example in your browser via JupyterLite or Binder .. rst-class:: sphx-glr-example-title .. _sphx_glr_auto_examples_ensemble_plot_random_forest_embedding.py: ========================================================= Hashing feature transformation using Totally Random Trees ========================================================= RandomTreesEmbedding provides a way to map data to a very high-dimensional, sparse representation, which might be beneficial for classification. The mapping is completely unsupervised and very efficient. This example visualizes the partitions given by several trees and shows how the transformation can also be used for non-linear dimensionality reduction or non-linear classification. Points that are neighboring often share the same leaf of a tree and therefore share large parts of their hashed representation. This allows to separate two concentric circles simply based on the principal components of the transformed data with truncated SVD. In high-dimensional spaces, linear classifiers often achieve excellent accuracy. For sparse binary data, BernoulliNB is particularly well-suited. The bottom row compares the decision boundary obtained by BernoulliNB in the transformed space with an ExtraTreesClassifier forests learned on the original data. .. GENERATED FROM PYTHON SOURCE LINES 28-109 .. image-sg:: /auto_examples/ensemble/images/sphx_glr_plot_random_forest_embedding_001.png :alt: Original Data (2d), Truncated SVD reduction (2d) of transformed data (74d), Naive Bayes on Transformed data, ExtraTrees predictions :srcset: /auto_examples/ensemble/images/sphx_glr_plot_random_forest_embedding_001.png :class: sphx-glr-single-img .. code-block:: Python import matplotlib.pyplot as plt import numpy as np from sklearn.datasets import make_circles from sklearn.decomposition import TruncatedSVD from sklearn.ensemble import ExtraTreesClassifier, RandomTreesEmbedding from sklearn.naive_bayes import BernoulliNB # make a synthetic dataset X, y = make_circles(factor=0.5, random_state=0, noise=0.05) # use RandomTreesEmbedding to transform data hasher = RandomTreesEmbedding(n_estimators=10, random_state=0, max_depth=3) X_transformed = hasher.fit_transform(X) # Visualize result after dimensionality reduction using truncated SVD svd = TruncatedSVD(n_components=2) X_reduced = svd.fit_transform(X_transformed) # Learn a Naive Bayes classifier on the transformed data nb = BernoulliNB() nb.fit(X_transformed, y) # Learn an ExtraTreesClassifier for comparison trees = ExtraTreesClassifier(max_depth=3, n_estimators=10, random_state=0) trees.fit(X, y) # scatter plot of original and reduced data fig = plt.figure(figsize=(9, 8)) ax = plt.subplot(221) ax.scatter(X[:, 0], X[:, 1], c=y, s=50, edgecolor="k") ax.set_title("Original Data (2d)") ax.set_xticks(()) ax.set_yticks(()) ax = plt.subplot(222) ax.scatter(X_reduced[:, 0], X_reduced[:, 1], c=y, s=50, edgecolor="k") ax.set_title( "Truncated SVD reduction (2d) of transformed data (%dd)" % X_transformed.shape[1] ) ax.set_xticks(()) ax.set_yticks(()) # Plot the decision in original space. For that, we will assign a color # to each point in the mesh [x_min, x_max]x[y_min, y_max]. h = 0.01 x_min, x_max = X[:, 0].min() - 0.5, X[:, 0].max() + 0.5 y_min, y_max = X[:, 1].min() - 0.5, X[:, 1].max() + 0.5 xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min, y_max, h)) # transform grid using RandomTreesEmbedding transformed_grid = hasher.transform(np.c_[xx.ravel(), yy.ravel()]) y_grid_pred = nb.predict_proba(transformed_grid)[:, 1] ax = plt.subplot(223) ax.set_title("Naive Bayes on Transformed data") ax.pcolormesh(xx, yy, y_grid_pred.reshape(xx.shape)) ax.scatter(X[:, 0], X[:, 1], c=y, s=50, edgecolor="k") ax.set_ylim(-1.4, 1.4) ax.set_xlim(-1.4, 1.4) ax.set_xticks(()) ax.set_yticks(()) # transform grid using ExtraTreesClassifier y_grid_pred = trees.predict_proba(np.c_[xx.ravel(), yy.ravel()])[:, 1] ax = plt.subplot(224) ax.set_title("ExtraTrees predictions") ax.pcolormesh(xx, yy, y_grid_pred.reshape(xx.shape)) ax.scatter(X[:, 0], X[:, 1], c=y, s=50, edgecolor="k") ax.set_ylim(-1.4, 1.4) ax.set_xlim(-1.4, 1.4) ax.set_xticks(()) ax.set_yticks(()) plt.tight_layout() plt.show() .. rst-class:: sphx-glr-timing **Total running time of the script:** (0 minutes 0.320 seconds) .. _sphx_glr_download_auto_examples_ensemble_plot_random_forest_embedding.py: .. only:: html .. container:: sphx-glr-footer sphx-glr-footer-example .. container:: binder-badge .. image:: images/binder_badge_logo.svg :target: https://mybinder.org/v2/gh/scikit-learn/scikit-learn/main?urlpath=lab/tree/notebooks/auto_examples/ensemble/plot_random_forest_embedding.ipynb :alt: Launch binder :width: 150 px .. container:: lite-badge .. image:: images/jupyterlite_badge_logo.svg :target: ../../lite/lab/?path=auto_examples/ensemble/plot_random_forest_embedding.ipynb :alt: Launch JupyterLite :width: 150 px .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: plot_random_forest_embedding.ipynb ` .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: plot_random_forest_embedding.py ` .. include:: plot_random_forest_embedding.recommendations .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_