From 3cdd1c16fb1b03892da1afd3d03b30fe0df80b5c Mon Sep 17 00:00:00 2001
From: Andrew Kane <andrew@ankane.org>
Date: Fri, 11 Feb 2022 13:55:39 -0800
Subject: [PATCH] Improved code [skip ci]

---
 src/ivfkmeans.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/ivfkmeans.c b/src/ivfkmeans.c
index fa7db49..60a07f7 100644
--- a/src/ivfkmeans.c
+++ b/src/ivfkmeans.c
@@ -121,15 +121,18 @@ QuickCenters(Relation index, VectorArray samples, VectorArray centers)
 	FmgrInfo   *normprocinfo = IvfflatOptionalProcInfo(index, IVFFLAT_KMEANS_NORM_PROC);
 
 	/* Copy existing vectors while avoiding duplicates */
-	qsort(samples->items, samples->length, VECTOR_SIZE(samples->dim), CompareVectors);
-	for (i = 0; i < samples->length; i++)
+	if (samples->length > 0)
 	{
-		vec = VectorArrayGet(samples, i);
-
-		if (i == 0 || CompareVectors(vec, VectorArrayGet(samples, i - 1)) != 0)
+		qsort(samples->items, samples->length, VECTOR_SIZE(samples->dim), CompareVectors);
+		for (i = 0; i < samples->length; i++)
 		{
-			VectorArraySet(centers, centers->length, vec);
-			centers->length++;
+			vec = VectorArrayGet(samples, i);
+
+			if (i == 0 || CompareVectors(vec, VectorArrayGet(samples, i - 1)) != 0)
+			{
+				VectorArraySet(centers, centers->length, vec);
+				centers->length++;
+			}
 		}
 	}