diff --git a/faiss/IndexHNSW.cpp b/faiss/IndexHNSW.cpp
index a9ebf27866..8c0e0afde8 100644
--- a/faiss/IndexHNSW.cpp
+++ b/faiss/IndexHNSW.cpp
@@ -87,6 +87,23 @@ struct NegativeDistanceComputer : DistanceComputer {
         return -(*basedis)(i);
     }
 
+    void distances_batch_4(
+            const idx_t idx0,
+            const idx_t idx1,
+            const idx_t idx2,
+            const idx_t idx3,
+            float& dis0,
+            float& dis1,
+            float& dis2,
+            float& dis3) override {
+        basedis->distances_batch_4(
+                idx0, idx1, idx2, idx3, dis0, dis1, dis2, dis3);
+        dis0 = -dis0;
+        dis1 = -dis1;
+        dis2 = -dis2;
+        dis3 = -dis3;
+    }
+
     /// compute distance between two stored vectors
     float symmetric_dis(idx_t i, idx_t j) override {
         return -basedis->symmetric_dis(i, j);