.. _sphx_glr_auto_examples_ensemble_plot_gradient_boosting_quantile.py: ===================================================== Prediction Intervals for Gradient Boosting Regression ===================================================== This example shows how quantile regression can be used to create prediction intervals. .. image:: /auto_examples/ensemble/images/sphx_glr_plot_gradient_boosting_quantile_001.png :align: center .. code-block:: python import numpy as np import matplotlib.pyplot as plt from sklearn.ensemble import GradientBoostingRegressor np.random.seed(1) def f(x): """The function to predict.""" return x * np.sin(x) #---------------------------------------------------------------------- # First the noiseless case X = np.atleast_2d(np.random.uniform(0, 10.0, size=100)).T X = X.astype(np.float32) # Observations y = f(X).ravel() dy = 1.5 + 1.0 * np.random.random(y.shape) noise = np.random.normal(0, dy) y += noise y = y.astype(np.float32) # Mesh the input space for evaluations of the real function, the prediction and # its MSE xx = np.atleast_2d(np.linspace(0, 10, 1000)).T xx = xx.astype(np.float32) alpha = 0.95 clf = GradientBoostingRegressor(loss='quantile', alpha=alpha, n_estimators=250, max_depth=3, learning_rate=.1, min_samples_leaf=9, min_samples_split=9) clf.fit(X, y) # Make the prediction on the meshed x-axis y_upper = clf.predict(xx) clf.set_params(alpha=1.0 - alpha) clf.fit(X, y) # Make the prediction on the meshed x-axis y_lower = clf.predict(xx) clf.set_params(loss='ls') clf.fit(X, y) # Make the prediction on the meshed x-axis y_pred = clf.predict(xx) # Plot the function, the prediction and the 90% confidence interval based on # the MSE fig = plt.figure() plt.plot(xx, f(xx), 'g:', label=u'$f(x) = x\,\sin(x)$') plt.plot(X, y, 'b.', markersize=10, label=u'Observations') plt.plot(xx, y_pred, 'r-', label=u'Prediction') plt.plot(xx, y_upper, 'k-') plt.plot(xx, y_lower, 'k-') plt.fill(np.concatenate([xx, xx[::-1]]), np.concatenate([y_upper, y_lower[::-1]]), alpha=.5, fc='b', ec='None', label='90% prediction interval') plt.xlabel('$x$') plt.ylabel('$f(x)$') plt.ylim(-10, 20) plt.legend(loc='upper left') plt.show() **Total running time of the script:** (0 minutes 0.312 seconds) .. container:: sphx-glr-download **Download Python source code:** :download:plot_gradient_boosting_quantile.py  .. container:: sphx-glr-download **Download IPython notebook:** :download:plot_gradient_boosting_quantile.ipynb