fix dnl_head export onnx inference difference type Cast error (open-mmlab#1161)

* fix export onnx inference difference type Cast error

* fix export onnx inference difference type Cast error.

* use yapf format

* use same device type with pairwise_weight

Author: sshuair

mmseg/models/decode_heads/dnl_head.py

@@ -26,8 +26,13 @@ def embedded_gaussian(self, theta_x, phi_x):
         pairwise_weight = torch.matmul(theta_x, phi_x)
         if self.use_scale:
             # theta_x.shape[-1] is `self.inter_channels`
-            pairwise_weight /= theta_x.shape[-1]**0.5
-        pairwise_weight /= self.temperature
+            pairwise_weight /= torch.tensor(
+                theta_x.shape[-1],
+                dtype=torch.float,
+                device=pairwise_weight.device)**torch.tensor(
+                    0.5, device=pairwise_weight.device)
+        pairwise_weight /= torch.tensor(
+            self.temperature, device=pairwise_weight.device)
         pairwise_weight = pairwise_weight.softmax(dim=-1)
         return pairwise_weight