Add assert in the conv2d_fft graph.

theano/sandbox/cuda/fftconv.py

@@ -453,6 +453,9 @@ def conv2d_fft(input, filters, image_shape=None, filter_shape=None,
     else:
         raise ValueError('invalid mode')
 
+    input_padded = T.opt.Assert("in conv2d_fft: width is not even")(
+        input_padded, o1 % 2 == 0)
+
     # reshape for FFT
     input_flat = input_padded.reshape((b * ic, o0, o1))
     filters_flat = filters_padded.reshape((oc * ic, o0, o1))