From 73eb40595df5c1dbe9f40a5eb42458f61a126198 Mon Sep 17 00:00:00 2001
From: Frank Dellaert <dellaert@gmail.com>
Date: Mon, 17 Jul 2023 17:14:24 +0200
Subject: [PATCH] use at(i) instead of [i]

---
 gtsam/inference/BayesTreeCliqueBase.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gtsam/inference/BayesTreeCliqueBase.h b/gtsam/inference/BayesTreeCliqueBase.h
index 171ebdc41..a7b1cf06c 100644
--- a/gtsam/inference/BayesTreeCliqueBase.h
+++ b/gtsam/inference/BayesTreeCliqueBase.h
@@ -147,7 +147,7 @@ namespace gtsam {
     size_t nrChildren() const { return children.size(); }
 
     /// Return the child at index i.
-    const derived_ptr operator[](size_t i) const { return children[i]; }
+    const derived_ptr operator[](size_t i) const { return children.at(i); }
 
     /** The size of subtree rooted at this clique, i.e., nr of Cliques */
     size_t treeSize() const;