From 4cb924aaadb230e9cad67982aba26189bba66671 Mon Sep 17 00:00:00 2001
From: Daniel Levi-Minzi <51272568+dleviminzi@users.noreply.github.com>
Date: Mon, 10 Jun 2024 14:56:42 -0400
Subject: [PATCH] Always Use Neon for L2 f32 (#20)

* use neon for vectors larger than 16 elements always

* remove commented out code
---
 sqlite-vec.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/sqlite-vec.c b/sqlite-vec.c
index b9b590f..e318907 100644
--- a/sqlite-vec.c
+++ b/sqlite-vec.c
@@ -186,8 +186,16 @@ static f32 l2_sqr_float_neon(const void *pVect1v, const void *pVect2v,
     sum3 = vfmaq_f32(sum3, diff, diff);
   }
 
-  return sqrt(
-      vaddvq_f32(vaddq_f32(vaddq_f32(sum0, sum1), vaddq_f32(sum2, sum3))));
+  f32 sum_scalar = vaddvq_f32(vaddq_f32(vaddq_f32(sum0, sum1), vaddq_f32(sum2, sum3)));
+  const f32 *pEnd2 = pVect1 + (qty - (qty16 << 4));
+  while (pVect1 < pEnd2) {
+    f32 diff = *pVect1 - *pVect2;
+    sum_scalar += diff * diff;
+    pVect1++;
+    pVect2++;
+  }
+
+  return sqrt(sum_scalar);
 }
 
 static f32 l2_sqr_int8_neon(const void *pVect1v, const void *pVect2v,
@@ -263,7 +271,7 @@ static f32 l2_sqr_int8(const void *pA, const void *pB, const void *pD) {
 
 static f32 distance_l2_sqr_float(const void *a, const void *b, const void *d) {
 #ifdef SQLITE_VEC_ENABLE_NEON
-  if (((*(const size_t *)d) % 16 == 0)) {
+  if ((*(const size_t *)d) > 16) {
     return l2_sqr_float_neon(a, b, d);
   }
 #endif