Minor changes

theano/tensor/signal/downsample.py

@@ -1123,6 +1123,8 @@ class DownsampleFactorMaxGradGrad(Op):
 @register_canonicalize
 @gof.local_optimizer([MaxPoolGrad])
 def local_average_pool_grad(node):
+    # To assure backward compatibility with
+    # DownsampleFactorMaxGrad
     if (not isinstance(node.op, MaxPoolGrad) or node.op.mode not in
             ['sum','average_exc_pad', 'average_inc_pad']):
         return False

theano/tensor/signal/tests/test_downsample.py

@@ -803,9 +803,9 @@ class TestDownsampleFactorMax(utt.InferShapeTester):
                                             warn=False)
 
     def test_opt_max_to_average(self):
-        im = theano.tensor.ftensor4()
-        maxout = theano.tensor.ftensor4()
-        grad = theano.tensor.ftensor4()
+        im = theano.tensor.tensor4()
+        maxout = theano.tensor.tensor4()
+        grad = theano.tensor.tensor4()
 
         for mode in ['max', 'sum', 'average_inc_pad', 'average_exc_pad']:
             f = theano.function([im, maxout, grad],