Pre-evaluation

src/distance.cpp

@@ -201,7 +201,7 @@ float DistanceL2Float::compare(const float *__restrict a, const float *__restric
 #ifdef USE_AVX2
     // assume size is divisible by 8
     uint16_t niters = (uint16_t)(size / 8);
-    uint32_t half = niters / 2, three_fourths = (niters * 3) / 4, seven_eights = (niters * 7) / 8;
+    uint32_t half = niters / 2, two_thirds = (niters * 2)/3, three_fourths = (niters * 3) / 4, seven_eights = (niters * 7) / 8;
     __m256 sum = _mm256_setzero_ps();
     for (uint16_t j = 0; j < niters; j++)
     {
@@ -220,11 +220,12 @@ float DistanceL2Float::compare(const float *__restrict a, const float *__restric
 
         sum = _mm256_fmadd_ps(tmp_vec, tmp_vec, sum);
 
-        if (j == half || j == three_fourths || j == seven_eights )
+        if (j == half || j == two_thirds || j == three_fourths /* || j == seven_eights*/)
         {
             if (_mm256_reduce_add_ps(sum) > threshold)
             {
-                //diskann::cout << "Breaking because sum exceeded threshold: " << threshold << std::endl;
+                //diskann::cout << "Breaking at " << j << " instead of " << niters
+                //              << " because sum exceeded threshold : " << threshold << std::endl;
                 return FLT_MAX;
             }
         }