diff --git a/src/ivfbuild.c b/src/ivfbuild.c
index b6a95e5..cf01334 100644
--- a/src/ivfbuild.c
+++ b/src/ivfbuild.c
@@ -437,7 +437,7 @@ ComputeCenters(IvfflatBuildState * buildstate)
 	}
 
 	/* Calculate centers */
-	IvfflatBench("k-means", IvfflatKmeans(buildstate->index, buildstate->samples, buildstate->centers));
+	IvfflatBench("k-means", IvfflatKmeans(buildstate->index, buildstate->samples, buildstate->centers, buildstate->type));
 
 	/* Free samples before we allocate more memory */
 	VectorArrayFree(buildstate->samples);
diff --git a/src/ivfflat.h b/src/ivfflat.h
index a3a378a..034a039 100644
--- a/src/ivfflat.h
+++ b/src/ivfflat.h
@@ -270,7 +270,7 @@ typedef IvfflatScanOpaqueData * IvfflatScanOpaque;
 /* Methods */
 VectorArray VectorArrayInit(int maxlen, int dimensions, Size itemsize);
 void		VectorArrayFree(VectorArray arr);
-void		IvfflatKmeans(Relation index, VectorArray samples, VectorArray centers);
+void		IvfflatKmeans(Relation index, VectorArray samples, VectorArray centers, IvfflatType type);
 FmgrInfo   *IvfflatOptionalProcInfo(Relation index, uint16 procnum);
 IvfflatType IvfflatGetType(Relation index);
 bool		IvfflatNormValue(FmgrInfo *procinfo, Oid collation, Datum *value, IvfflatType type);
diff --git a/src/ivfkmeans.c b/src/ivfkmeans.c
index f739e7d..bb1734b 100644
--- a/src/ivfkmeans.c
+++ b/src/ivfkmeans.c
@@ -112,7 +112,7 @@ CompareVectors(const void *a, const void *b)
  * Quick approach if we have little data
  */
 static void
-QuickCenters(Relation index, VectorArray samples, VectorArray centers)
+QuickCenters(Relation index, VectorArray samples, VectorArray centers, IvfflatType type)
 {
 	int			dimensions = centers->dim;
 	Oid			collation = index->rd_indcollation[0];
@@ -121,7 +121,11 @@ QuickCenters(Relation index, VectorArray samples, VectorArray centers)
 	/* Copy existing vectors while avoiding duplicates */
 	if (samples->length > 0)
 	{
-		qsort(samples->items, samples->length, samples->itemsize, CompareVectors);
+		if (type == IVFFLAT_TYPE_VECTOR)
+			qsort(samples->items, samples->length, samples->itemsize, CompareVectors);
+		else
+			elog(ERROR, "Unsupported type");
+
 		for (int i = 0; i < samples->length; i++)
 		{
 			Datum	   vec = PointerGetDatum(VectorArrayGet(samples, i));
@@ -137,17 +141,22 @@ QuickCenters(Relation index, VectorArray samples, VectorArray centers)
 	/* Fill remaining with random data */
 	while (centers->length < centers->maxlen)
 	{
-		Vector	   *vec = (Vector *) VectorArrayGet(centers, centers->length);
+		if (type == IVFFLAT_TYPE_VECTOR)
+		{
+			Vector	   *vec = (Vector *) VectorArrayGet(centers, centers->length);
 
-		SET_VARSIZE(vec, VECTOR_SIZE(dimensions));
-		vec->dim = dimensions;
+			SET_VARSIZE(vec, VECTOR_SIZE(dimensions));
+			vec->dim = dimensions;
 
-		for (int j = 0; j < dimensions; j++)
-			vec->x[j] = RandomDouble();
+			for (int j = 0; j < dimensions; j++)
+				vec->x[j] = RandomDouble();
 
-		/* Normalize if needed (only needed for random centers) */
-		if (normprocinfo != NULL)
-			ApplyNorm(normprocinfo, collation, vec);
+			/* Normalize if needed (only needed for random centers) */
+			if (normprocinfo != NULL)
+				ApplyNorm(normprocinfo, collation, vec);
+		}
+		else
+			elog(ERROR, "Unsupported type");
 
 		centers->length++;
 	}
@@ -179,7 +188,7 @@ ShowMemoryUsage(Size estimatedSize)
  * https://www.aaai.org/Papers/ICML/2003/ICML03-022.pdf
  */
 static void
-ElkanKmeans(Relation index, VectorArray samples, VectorArray centers)
+ElkanKmeans(Relation index, VectorArray samples, VectorArray centers, IvfflatType type)
 {
 	FmgrInfo   *procinfo;
 	FmgrInfo   *normprocinfo;
@@ -483,7 +492,7 @@ ElkanKmeans(Relation index, VectorArray samples, VectorArray centers)
  * Detect issues with centers
  */
 static void
-CheckCenters(Relation index, VectorArray centers)
+CheckCenters(Relation index, VectorArray centers, IvfflatType type)
 {
 	FmgrInfo   *normprocinfo;
 
@@ -507,7 +516,11 @@ CheckCenters(Relation index, VectorArray centers)
 
 	/* Ensure no duplicate centers */
 	/* Fine to sort in-place */
-	qsort(centers->items, centers->length, centers->itemsize, CompareVectors);
+	if (type == IVFFLAT_TYPE_VECTOR)
+		qsort(centers->items, centers->length, centers->itemsize, CompareVectors);
+	else
+		elog(ERROR, "Unsupported type");
+
 	for (int i = 1; i < centers->length; i++)
 	{
 		if (datumIsEqual(PointerGetDatum(VectorArrayGet(centers, i)), PointerGetDatum(VectorArrayGet(centers, i - 1)), false, -1))
@@ -536,12 +549,12 @@ CheckCenters(Relation index, VectorArray centers)
  * We use spherical k-means for inner product and cosine
  */
 void
-IvfflatKmeans(Relation index, VectorArray samples, VectorArray centers)
+IvfflatKmeans(Relation index, VectorArray samples, VectorArray centers, IvfflatType type)
 {
 	if (samples->length <= centers->maxlen)
-		QuickCenters(index, samples, centers);
+		QuickCenters(index, samples, centers, type);
 	else
-		ElkanKmeans(index, samples, centers);
+		ElkanKmeans(index, samples, centers, type);
 
-	CheckCenters(index, centers);
+	CheckCenters(index, centers, type);
 }