{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "\n# Gaussian process classification (GPC) on iris dataset\n\nThis example illustrates the predicted probability of GPC for an isotropic\nand anisotropic RBF kernel on a two-dimensional version for the iris-dataset.\nThe anisotropic RBF kernel obtains slightly higher log-marginal-likelihood by\nassigning different length-scales to the two feature dimensions.\n" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": false }, "outputs": [], "source": [ "# Authors: The scikit-learn developers\n# SPDX-License-Identifier: BSD-3-Clause\n\nimport matplotlib.pyplot as plt\nimport numpy as np\n\nfrom sklearn import datasets\nfrom sklearn.gaussian_process import GaussianProcessClassifier\nfrom sklearn.gaussian_process.kernels import RBF\n\n# import some data to play with\niris = datasets.load_iris()\nX = iris.data[:, :2] # we only take the first two features.\ny = np.array(iris.target, dtype=int)\n\nh = 0.02 # step size in the mesh\n\nkernel = 1.0 * RBF([1.0])\ngpc_rbf_isotropic = GaussianProcessClassifier(kernel=kernel).fit(X, y)\nkernel = 1.0 * RBF([1.0, 1.0])\ngpc_rbf_anisotropic = GaussianProcessClassifier(kernel=kernel).fit(X, y)\n\n# create a mesh to plot in\nx_min, x_max = X[:, 0].min() - 1, X[:, 0].max() + 1\ny_min, y_max = X[:, 1].min() - 1, X[:, 1].max() + 1\nxx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min, y_max, h))\n\ntitles = [\"Isotropic RBF\", \"Anisotropic RBF\"]\nplt.figure(figsize=(10, 5))\nfor i, clf in enumerate((gpc_rbf_isotropic, gpc_rbf_anisotropic)):\n # Plot the predicted probabilities. For that, we will assign a color to\n # each point in the mesh [x_min, m_max]x[y_min, y_max].\n plt.subplot(1, 2, i + 1)\n\n Z = clf.predict_proba(np.c_[xx.ravel(), yy.ravel()])\n\n # Put the result into a color plot\n Z = Z.reshape((xx.shape[0], xx.shape[1], 3))\n plt.imshow(Z, extent=(x_min, x_max, y_min, y_max), origin=\"lower\")\n\n # Plot also the training points\n plt.scatter(X[:, 0], X[:, 1], c=np.array([\"r\", \"g\", \"b\"])[y], edgecolors=(0, 0, 0))\n plt.xlabel(\"Sepal length\")\n plt.ylabel(\"Sepal width\")\n plt.xlim(xx.min(), xx.max())\n plt.ylim(yy.min(), yy.max())\n plt.xticks(())\n plt.yticks(())\n plt.title(\n \"%s, LML: %.3f\" % (titles[i], clf.log_marginal_likelihood(clf.kernel_.theta))\n )\n\nplt.tight_layout()\nplt.show()" ] } ], "metadata": { "kernelspec": { "display_name": "Python 3", "language": "python", "name": "python3" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 3 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython3", "version": "3.9.21" } }, "nbformat": 4, "nbformat_minor": 0 }