From b039dd10828c3c7947a42036772f7d1a51fec9cd Mon Sep 17 00:00:00 2001
From: Gregory Shklover <gregory.shklover@gmail.com>
Date: Thu, 22 Sep 2022 07:27:48 +0000
Subject: [PATCH] Small performance improvement to simplex

---
 lib/common/ns.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/common/ns.c b/lib/common/ns.c
index 89613d5f3..42fdff6fb 100644
--- a/lib/common/ns.c
+++ b/lib/common/ns.c
@@ -471,11 +471,13 @@ subtree_t *merge_trees(Agedge_t *e)   /* entering tree edge */
 
   if (t0->heap_index == -1) {   // move t0
     delta = SLACK(e);
-    tree_adjust(t0->rep,NULL,delta);
+    if (delta != 0)
+      tree_adjust(t0->rep,NULL,delta);
   }
   else {  // move t1
     delta = -SLACK(e);
-    tree_adjust(t1->rep,NULL,delta);
+    if (delta != 0)
+      tree_adjust(t1->rep,NULL,delta);
   }
   if (add_tree_edge(e) != 0) {
     return NULL;
-- 
2.40.0