.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "auto_examples/model_selection/plot_randomized_search.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_model_selection_plot_randomized_search.py: ========================================================================= Comparing randomized search and grid search for hyperparameter estimation ========================================================================= Compare randomized search and grid search for optimizing hyperparameters of a linear SVM with SGD training. All parameters that influence the learning are searched simultaneously (except for the number of estimators, which poses a time / quality tradeoff). The randomized search and the grid search explore exactly the same space of parameters. The result in parameter settings is quite similar, while the run time for randomized search is drastically lower. The performance is may slightly worse for the randomized search, and is likely due to a noise effect and would not carry over to a held-out test set. Note that in practice, one would not search over this many different parameters simultaneously using grid search, but pick only the ones deemed most important. .. GENERATED FROM PYTHON SOURCE LINES 22-93 .. rst-class:: sphx-glr-script-out .. code-block:: none RandomizedSearchCV took 0.85 seconds for 15 candidates parameter settings. Model with rank: 1 Mean validation score: 0.991 (std: 0.006) Parameters: {'alpha': 0.05063247886572012, 'average': False, 'l1_ratio': 0.13822072286080167} Model with rank: 2 Mean validation score: 0.987 (std: 0.014) Parameters: {'alpha': 0.010877306503748912, 'average': True, 'l1_ratio': 0.9226260871125187} Model with rank: 3 Mean validation score: 0.976 (std: 0.023) Parameters: {'alpha': 0.727148206404819, 'average': False, 'l1_ratio': 0.25183501383331797} GridSearchCV took 2.82 seconds for 60 candidate parameter settings. Model with rank: 1 Mean validation score: 0.993 (std: 0.011) Parameters: {'alpha': 0.1, 'average': False, 'l1_ratio': 0.1111111111111111} Model with rank: 2 Mean validation score: 0.987 (std: 0.013) Parameters: {'alpha': 0.01, 'average': False, 'l1_ratio': 0.5555555555555556} Model with rank: 3 Mean validation score: 0.987 (std: 0.007) Parameters: {'alpha': 0.01, 'average': False, 'l1_ratio': 0.0} | .. code-block:: Python from time import time import numpy as np import scipy.stats as stats from sklearn.datasets import load_digits from sklearn.linear_model import SGDClassifier from sklearn.model_selection import GridSearchCV, RandomizedSearchCV # get some data X, y = load_digits(return_X_y=True, n_class=3) # build a classifier clf = SGDClassifier(loss="hinge", penalty="elasticnet", fit_intercept=True) # Utility function to report best scores def report(results, n_top=3): for i in range(1, n_top + 1): candidates = np.flatnonzero(results["rank_test_score"] == i) for candidate in candidates: print("Model with rank: {0}".format(i)) print( "Mean validation score: {0:.3f} (std: {1:.3f})".format( results["mean_test_score"][candidate], results["std_test_score"][candidate], ) ) print("Parameters: {0}".format(results["params"][candidate])) print("") # specify parameters and distributions to sample from param_dist = { "average": [True, False], "l1_ratio": stats.uniform(0, 1), "alpha": stats.loguniform(1e-2, 1e0), } # run randomized search n_iter_search = 15 random_search = RandomizedSearchCV( clf, param_distributions=param_dist, n_iter=n_iter_search ) start = time() random_search.fit(X, y) print( "RandomizedSearchCV took %.2f seconds for %d candidates parameter settings." % ((time() - start), n_iter_search) ) report(random_search.cv_results_) # use a full grid over all parameters param_grid = { "average": [True, False], "l1_ratio": np.linspace(0, 1, num=10), "alpha": np.power(10, np.arange(-2, 1, dtype=float)), } # run grid search grid_search = GridSearchCV(clf, param_grid=param_grid) start = time() grid_search.fit(X, y) print( "GridSearchCV took %.2f seconds for %d candidate parameter settings." % (time() - start, len(grid_search.cv_results_["params"])) ) report(grid_search.cv_results_) .. rst-class:: sphx-glr-timing **Total running time of the script:** (0 minutes 3.678 seconds) .. _sphx_glr_download_auto_examples_model_selection_plot_randomized_search.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/model_selection/plot_randomized_search.ipynb :alt: Launch binder :width: 150 px .. container:: lite-badge .. image:: images/jupyterlite_badge_logo.svg :target: ../../lite/lab/?path=auto_examples/model_selection/plot_randomized_search.ipynb :alt: Launch JupyterLite :width: 150 px .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: plot_randomized_search.ipynb ` .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: plot_randomized_search.py ` .. include:: plot_randomized_search.recommendations .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_