improved input validation

theano/sandbox/cuda/blas.py

@@ -2169,6 +2169,17 @@ class GpuDownsampleFactorMaxGradGrad(GpuOp):
         self.ignore_border = ignore_border
 
     def make_node(self, x, z, gx):
+        x = as_cuda_ndarray_variable(x)
+        z = as_cuda_ndarray_variable(z)
+        gx = as_cuda_ndarray_variable(gx)
+        
+        if x.type.ndim != 4:
+            raise TypeError('x must be 4D tensor')
+        if z.type.ndim != 4:
+            raise TypeError('z must be 4D tensor')
+        if gx.type.ndim != 4:
+            raise TypeError('gx must be 4D tensor')
+        
         return Apply(self, [x, z, gx], [x.type()])
 
     def c_code_cache_version(self):
@@ -2262,8 +2273,6 @@ class GpuDownsampleFactorMaxGradGrad(GpuOp):
         """ % locals()
 
     def c_support_code_apply(self, node, nodename):
-        ignore_border = int(self.ignore_border)
-
         return """
         // ds0 is the downsampling factor in rows, ds1 in columns
         template<int ds0, int ds1>