ENH: ElasticNetCV and LassoCV raise ValueError with multitarget outputs

MechCoder · agramfort · commit af8904cf0f28 · 2013-11-17T20:14:33.000+01:00
diff --git a/sklearn/linear_model/coordinate_descent.py b/sklearn/linear_model/coordinate_descent.py
@@ -916,6 +916,10 @@ def fit(self, X, y):
             copy_X = False
 
         y = np.asarray(y, dtype=np.float64)
+
+        if y.ndim > 1:
+            raise ValueError("For multi-task outputs, fit the linear model "
+                             "per output/task")
         if X.shape[0] != y.shape[0]:
             raise ValueError("X and y have inconsistent dimensions (%d != %d)"
                              % (X.shape[0], y.shape[0]))
diff --git a/sklearn/linear_model/tests/test_coordinate_descent.py b/sklearn/linear_model/tests/test_coordinate_descent.py
@@ -14,6 +14,7 @@
 from sklearn.utils.testing import SkipTest
 from sklearn.utils.testing import assert_true
 from sklearn.utils.testing import assert_greater
+from sklearn.utils.testing import assert_raises
 
 from sklearn.linear_model.coordinate_descent import Lasso, \
     LassoCV, ElasticNet, ElasticNetCV, MultiTaskLasso, MultiTaskElasticNet, \
@@ -336,6 +337,13 @@ def test_enet_multitarget():
         assert_array_almost_equal(dual_gap[k], estimator.dual_gap_)
 
 
+def test_multioutput_enetcv_error():
+    X = np.random.randn(10, 2)
+    y = np.random.randn(10, 2)
+    clf = ElasticNetCV()
+    assert_raises(ValueError, clf.fit, X, y)
+
+
 if __name__ == '__main__':
     import nose
     nose.runmodule()
