def test_lasso_cv(): X, y, X_test, y_test = build_dataset() max_iter = 150 clf = LassoCV(n_alphas=10, eps=1e-3, max_iter=max_iter).fit(X, y) assert_almost_equal(clf.alpha_, 0.056, 2) clf = LassoCV(n_alphas=10, eps=1e-3, max_iter=max_iter, precompute=True) clf.fit(X, y) assert_almost_equal(clf.alpha_, 0.056, 2) # Check that the lars and the coordinate descent implementation # select a similar alpha lars = LassoLarsCV(normalize=False, max_iter=30).fit(X, y) # for this we check that they don't fall in the grid of # clf.alphas further than 1 assert_true(np.abs( np.searchsorted(clf.alphas_[::-1], lars.alpha_) - np.searchsorted(clf.alphas_[::-1], clf.alpha_)) <= 1) # check that they also give a similar MSE mse_lars = interpolate.interp1d(lars.cv_alphas_, lars.mse_path_.T) np.testing.assert_approx_equal(mse_lars(clf.alphas_[5]).mean(), clf.mse_path_[5].mean(), significant=2) # test set assert_greater(clf.score(X_test, y_test), 0.99)
def test_lasso_cv(): X, y, X_test, y_test = build_dataset() max_iter = 150 clf = LassoCV(n_alphas=10, eps=1e-3, max_iter=max_iter).fit(X, y) assert_almost_equal(clf.alpha_, 0.056, 2) clf = LassoCV(n_alphas=10, eps=1e-3, max_iter=max_iter, precompute=True) clf.fit(X, y) assert_almost_equal(clf.alpha_, 0.056, 2) # Check that the lars and the coordinate descent implementation # select a similar alpha lars = LassoLarsCV(normalize=False, max_iter=30).fit(X, y) # for this we check that they don't fall in the grid of # clf.alphas further than 1 assert_true(np.abs( np.searchsorted(clf.alphas_[::-1], lars.alpha_) - np.searchsorted(clf.alphas_[::-1], clf.alpha_)) <= 1) # check that they also give a similar MSE mse_lars = interpolate.interp1d(lars.cv_alphas_, lars.cv_mse_path_.T) np.testing.assert_approx_equal(mse_lars(clf.alphas_[5]).mean(), clf.mse_path_[5].mean(), significant=2) # test set assert_greater(clf.score(X_test, y_test), 0.99)
def test_lasso_path(): X, y, X_test, y_test = build_dataset() max_iter = 50 clf = LassoCV(n_alphas=10, eps=1e-3, max_iter=max_iter).fit(X, y) assert_almost_equal(clf.alpha, 0.011, 2) clf = LassoCV(n_alphas=10, eps=1e-3, max_iter=max_iter, precompute=True) clf.fit(X, y) assert_almost_equal(clf.alpha, 0.011, 2) # test set assert clf.score(X_test, y_test) > 0.85
def test_lasso_path(): # build an ill-posed linear regression problem with many noisy features and # comparatively few samples n_samples, n_features, max_iter = 50, 200, 30 random_state = np.random.RandomState(0) w = random_state.randn(n_features) w[10:] = 0.0 # only the top 10 features are impacting the model X = random_state.randn(n_samples, n_features) y = np.dot(X, w) clf = LassoCV(n_alphas=10, eps=1e-3, max_iter=max_iter).fit(X, y) assert_almost_equal(clf.alpha, 0.011, 2) clf = LassoCV(n_alphas=10, eps=1e-3, max_iter=max_iter, precompute=True) clf.fit(X, y) assert_almost_equal(clf.alpha, 0.011, 2) # test set X_test = random_state.randn(n_samples, n_features) y_test = np.dot(X_test, w) assert clf.score(X_test, y_test) > 0.85