update to infer_shape in PermuteRowElements

theano/tensor/basic.py

@@ -5816,14 +5816,10 @@ class PermuteRowElements(Op):
     def infer_shape(self, node, in_shapes):
         shp_x = in_shapes[0]
         shp_y = in_shapes[1]
-        if len(shp_x) > len(shp_y):
-            out_shape = shp_x
-        elif len(shp_x) < len(shp_y):
-            out_shape = shp_y
-        else:
-            out_shape = []
-            for i in range(len(shp_x)):
-                out_shape.append(maximum(shp_x[i], shp_y[i]))
+        assert len(shp_x) == len(shp_y)
+        out_shape = []
+        for i in range(len(shp_x)):
+            out_shape.append(maximum(shp_x[i], shp_y[i]))
         return [out_shape]
 
     def grad(self, inp, grads):