Fix return value of R_op in HostFromGpu/GpuFromHost

theano/sandbox/cuda/basic_ops.py

@@ -92,7 +92,7 @@ class HostFromGpu(GpuOp):
 
     def R_op(self, inputs, eval_points):
         ev, = eval_points
-        return self(ev)
+        return [self(ev)]
 
     def infer_shape(self, node, xshp):
         return xshp
@@ -152,7 +152,7 @@ class GpuFromHost(GpuOp):
 
     def R_op(self, inputs, eval_points):
         ev, = eval_points
-        self(ev)
+        [self(ev)]
 
     def infer_shape(self, node, xshp):
         return xshp

theano/sandbox/gpuarray/basic_ops.py

@@ -345,7 +345,7 @@ class HostFromGpu(Op):
 
     def R_op(self, inputs, eval_points):
         ev, = eval_points
-        return self(ev)
+        return [self(ev)]
 
     def infer_shape(self, node, xshp):
         return xshp
@@ -386,7 +386,7 @@ class GpuFromHost(Op):
 
     def R_op(self, inputs, eval_points):
         ev, = eval_points
-        return self(ev)
+        return [self(ev)]
 
     def infer_shape(self, node, xshp):
         return xshp