Convert inputs of maxpool to tensor

theano/tensor/signal/downsample.py

@@ -208,7 +208,8 @@ class DownsampleFactorMax(Op):
     def make_node(self, x):
         if x.type.ndim != 4:
             raise TypeError()
-        # TODO: consider restrucing the dtype?
+        # TODO: consider restricting the dtype?
+        x = tensor.as_tensor_variable(x)
         return gof.Apply(self, [x], [x.type()])
 
     def perform(self, node, inp, out):
@@ -371,6 +372,9 @@ class DownsampleFactorMaxGrad(Op):
         assert isinstance(x, Variable) and x.ndim == 4
         assert isinstance(maxout, Variable) and maxout.ndim == 4
         assert isinstance(gz, Variable) and gz.ndim == 4
+        x = tensor.as_tensor_variable(x)
+        maxout = tensor.as_tensor_variable(maxout)
+        gz = tensor.as_tensor_variable(gz)
 
         return Apply(self, [x, maxout, gz], [x.type()])
 
@@ -625,6 +629,9 @@ class DownsampleFactorMaxGradGrad(Op):
         assert isinstance(x, Variable) and x.ndim == 4
         assert isinstance(maxout, Variable) and maxout.ndim == 4
         assert isinstance(gz, Variable) and gz.ndim == 4
+        x = tensor.as_tensor_variable(x)
+        maxout = tensor.as_tensor_variable(maxout)
+        gz = tensor.as_tensor_variable(gz)
 
         return Apply(self, [x, maxout, gz], [x.type()])