From 3e8807b5750d00c471241b88e785847d24921562 Mon Sep 17 00:00:00 2001
From: Duy-Nguyen Ta <thduynguyen@gmail.com>
Date: Sun, 8 Oct 2017 22:06:44 -0400
Subject: [PATCH] fix constness

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

diff --git a/gtsam.h b/gtsam.h
index e679b6838..e500c6328 100644
--- a/gtsam.h
+++ b/gtsam.h
@@ -164,7 +164,7 @@ class KeySet {
 
   // structure specific methods
   void insert(size_t key);
-  void merge(gtsam::KeySet& other);
+  void merge(const gtsam::KeySet& other);
   bool erase(size_t key); // returns true if value was removed
   bool count(size_t key) const; // returns true if value exists