From 45e624b676985981d77dc607778b9996b1c07306 Mon Sep 17 00:00:00 2001
From: pancan21 <75097835+pancan21@users.noreply.github.com>
Date: Mon, 17 Nov 2025 16:08:54 +0100
Subject: [PATCH] Change is_diff check to use is_diff.any()

Previous implementation using list of boolean values resulted in ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

I assume using any() instead of all() is the intended behavior.
---
 tensordict/_td.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tensordict/_td.py b/tensordict/_td.py
index 57529590d..73dd4d800 100644
--- a/tensordict/_td.py
+++ b/tensordict/_td.py
@@ -2579,7 +2579,7 @@ def _set_at_str(self, key, value, idx, *, validated, non_blocking: bool):
                     ignore_lock=True,
                 )
             is_diff = dest[idx].tolist() != value.tolist()
-            if is_diff:
+            if is_diff.any():
                 dest_val = dest.maybe_to_stack()
                 dest_val[idx] = value
                 if dest_val is not dest: