Merge branch 'develop-add-fire-checkpoint' of https://github.com/Unity-Technologies/ml-agents into develop-add-fire-checkpoint

ml-agents/mlagents/trainers/torch/networks.py

         memories: Optional[torch.Tensor] = None,
         sequence_length: int = 1,
     ) -> Tuple[torch.Tensor, torch.Tensor]:
-        vec_encodes = []
+        encodes = []
         for idx, encoder in enumerate(self.vector_encoders):
             vec_input = vec_inputs[idx]
             if actions is not None:
-            vec_encodes.append(hidden)
+            encodes.append(hidden)
-        vis_encodes = []
-            vis_encodes.append(hidden)
+            encodes.append(hidden)
-        if len(vec_encodes) > 0 and len(vis_encodes) > 0:
-            vec_encodes_tensor = torch.stack(vec_encodes, dim=-1).sum(dim=-1)
-            vis_encodes_tensor = torch.stack(vis_encodes, dim=-1).sum(dim=-1)
-            encoding = torch.stack(
-                [vec_encodes_tensor, vis_encodes_tensor], dim=-1
-            ).sum(dim=-1)
-        elif len(vec_encodes) > 0:
-            encoding = torch.stack(vec_encodes, dim=-1).sum(dim=-1)
-        elif len(vis_encodes) > 0:
-            encoding = torch.stack(vis_encodes, dim=-1).sum(dim=-1)
-        else:
+        if len(encodes) == 0:
+
+        # Constants don't work in Barracuda
+        encoding = encodes[0]
+        if len(encodes) > 1:
+            for _enc in encodes[1:]:
+                encoding += _enc
 
         if self.use_lstm:
             encoding = encoding.view([sequence_length, -1, self.h_size])
         )
         action_list = self.sample_action(dists)
         sampled_actions = torch.stack(action_list, dim=-1)
+        if self.act_type == ActionType.CONTINUOUS:
+            log_probs = dists[0].log_prob(sampled_actions)
+        else:
+            log_probs = dists[0].all_log_prob()
-            dists[0].pdf(sampled_actions),
+            log_probs,
             self.version_number,
             self.memory_size,
             self.is_continuous_int,