Update

[ghstack-poisoned]
pytorch · Dec 15, 2024 · 67a91d4 · 67a91d4
2 parents 98d7450 + 54d9949
commit 67a91d4
Showing 1 changed file with 23 additions and 10 deletions.
diff --git a/torchrl/objectives/iql.py b/torchrl/objectives/iql.py
@@ -785,12 +785,15 @@ def actor_loss(self, tensordict: TensorDictBase) -> Tuple[Tensor, dict]:
         state_action_value = td_q.get(self.tensor_keys.state_action_value)
         action = tensordict.get(self.tensor_keys.action)
         if self.action_space == "categorical":
-            if action.ndim < state_action_value.ndim:
+            if action.ndim < (state_action_value.ndim - (td_q.ndim - tensordict.ndim)):
                 # unsqueeze the action if it lacks on trailing singleton dim
                 action = action.unsqueeze(-1)
-            chosen_state_action_value = torch.gather(
-                state_action_value, -1, index=action
-            ).squeeze(-1)
+            chosen_state_action_value = torch.vmap(
+                lambda state_action_value, action: torch.gather(
+                    state_action_value, -1, index=action
+                ).squeeze(-1),
+                (0, None),
+            )(state_action_value, action)
         elif self.action_space == "one_hot":
             action = action.to(torch.float)
             chosen_state_action_value = (state_action_value * action).sum(-1)
@@ -830,12 +833,17 @@ def value_loss(self, tensordict: TensorDictBase) -> Tuple[Tensor, dict]:
             state_action_value = td_q.get(self.tensor_keys.state_action_value)
             action = tensordict.get(self.tensor_keys.action)
             if self.action_space == "categorical":
-                if action.ndim < state_action_value.ndim:
+                if action.ndim < (
+                    state_action_value.ndim - (td_q.ndim - tensordict.ndim)
+                ):
                     # unsqueeze the action if it lacks on trailing singleton dim
                     action = action.unsqueeze(-1)
-                chosen_state_action_value = torch.gather(
-                    state_action_value, -1, index=action
-                ).squeeze(-1)
+                chosen_state_action_value = torch.vmap(
+                    lambda state_action_value, action: torch.gather(
+                        state_action_value, -1, index=action
+                    ).squeeze(-1),
+                    (0, None),
+                )(state_action_value, action)
             elif self.action_space == "one_hot":
                 action = action.to(torch.float)
                 chosen_state_action_value = (state_action_value * action).sum(-1)
@@ -867,10 +875,15 @@ def qvalue_loss(self, tensordict: TensorDictBase) -> Tuple[Tensor, dict]:
         state_action_value = td_q.get(self.tensor_keys.state_action_value)
         action = tensordict.get(self.tensor_keys.action)
         if self.action_space == "categorical":
-            if action.ndim < state_action_value.ndim:
+            if action.ndim < (state_action_value.ndim - (td_q.ndim - tensordict.ndim)):
                 # unsqueeze the action if it lacks on trailing singleton dim
                 action = action.unsqueeze(-1)
-            pred_val = torch.gather(state_action_value, -1, index=action).squeeze(-1)
+            pred_val = torch.vmap(
+                lambda state_action_value, action: torch.gather(
+                    state_action_value, -1, index=action
+                ).squeeze(-1),
+                (0, None),
+            )(state_action_value, action)
         elif self.action_space == "one_hot":
             action = action.to(torch.float)
             pred_val = (state_action_value * action).sum(-1)