* lib.c (quicksort): Incorrect pivot selection.

2 files changed, 5 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 9e354cb2..23c623da 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2012-02-22  Kaz Kylheku  <kaz@kylheku.com>
 
+	* lib.c (quicksort): Incorrect pivot selection.
+
+2012-02-22  Kaz Kylheku  <kaz@kylheku.com>
+
 	* eval.c (del_s): New symbol variable.
 	(eval_error): nostatic added to suppress a g++ warning.
 	(dwim_loc): Takes new value as the original unevaluated form so
diff --git a/lib.c b/lib.c
index 35395a7c..d405a991 100644
--- a/lib.c
+++ b/lib.c
@@ -3578,7 +3578,7 @@ static void swap(val vec, val i, val j)
 static void quicksort(val vec, val lessfun, val keyfun, cnum from, cnum to)
 {
   if (to - from >= 2) {
-    cnum pivot = (to - from) / 2;
+    cnum pivot = to + (to - from) / 2;
     cnum i, j;
     val pval = ref(vec, num_fast(pivot));
     val pkval = funcall1(keyfun, pval);