Update error message

theano/tensor/sort.py

@@ -61,7 +61,7 @@ class SortOp(theano.Op):
         inp_grad = theano.gradient.grad_not_implemented(
             self, 0, axis,
             "Currently, we only implement the gradient on sort for vector"
-            " and matrix (and axis is None)")
+            " and matrix (and axis is None or 0)")
         if a.ndim == 1:
             idx = argsort(*inputs, kind=self.kind, order=self.order)
 #            rev_idx = numpy.where(idx[None, :]==numpy.arange(5)[:,None])[1]