fixed bugs introduced by recent commits

theano/gradient.py

@@ -668,8 +668,9 @@ def _populate_grad_dict(var_to_node_to_idx,
     # its inputs' gradients
     term_dict = {}
 
-    # populate term_dict[node] and return it
     def access_term_cache(node):
+        """ Populates term_dict[node] and returns it """
+
         if node not in term_dict:
 
             inputs = node.inputs
@@ -684,15 +685,13 @@ def _populate_grad_dict(var_to_node_to_idx,
 
             # list of bools indicating if each input is connected to the cost
             inputs_connected = [
-                    [ input_to_output and output_to_cost for
+                    (True in [ input_to_output and output_to_cost for
                         input_to_output, output_to_cost in
-                        zip(input_to_outputs, outputs_connected) ] for
+                        zip(input_to_outputs, outputs_connected) ]) for
                         input_to_outputs in connection_pattern
                     ]
 
-            all_inputs_disconnected = not ( True in inputs_connected )
-
-            if all_inputs_disconnected:
+            if True in inputs_connected:
                 # At least one input of this op is connected to the cost so we must
                 # call the op's grad method
 
@@ -763,7 +762,7 @@ def _populate_grad_dict(var_to_node_to_idx,
                             node.op, g_r_type, i, r_type)
 
             #cache the result
-            term_dict[node] = list(input_grads)
+            term_dict[node] = input_grads
 
         return term_dict[node]