Fix Ridge floating point instability (#8154)

lesteve · jnothman · commit 899885640626 · 2017-01-07T21:47:16.000+11:00
diff --git a/sklearn/linear_model/ridge.py b/sklearn/linear_model/ridge.py
@@ -885,7 +885,7 @@ def _errors_and_values_helper(self, alpha, y, v, Q, QT_y):
         constant_column = np.var(Q, 0) < 1.e-12
         # detect constant columns
         w[constant_column] = 0  # cancel the regularization for the intercept
-        w[v == 0] = 0
+
         c = np.dot(Q, self._diag_dot(w, QT_y))
         G_diag = self._decomp_diag(w, Q)
         # handle case where y is 2-d
