naive implementation of L2

src/VecSim/spaces/L2/L2.cpp

@@ -7,6 +7,7 @@
 #include "L2.h"
 #include "VecSim/types/bfloat16.h"
 #include "VecSim/types/float16.h"
+#include "VecSim/types/int8.h"
 #include <cstring>
 
 using bfloat16 = vecsim_types::bfloat16;
@@ -70,3 +71,26 @@ float FP16_L2Sqr(const void *pVect1, const void *pVect2, size_t dimension) {
     }
     return res;
 }
+
+template <bool is_little>
+float INT8_L2Sqr(const void *pVect1v, const void *pVect2v, size_t dimension) {
+    int8_t *pVect1 = (int8_t *)pVect1v;
+    int8_t *pVect2 = (int8_t *)pVect2v;
+
+    int res = 0;
+    for (size_t i = 0; i < dimension; i++) {
+        int16_t a = vecsim_types::int8_to_int16<is_little>(pVect1[i]);
+        int16_t b = vecsim_types::int8_to_int16<is_little>(pVect2[i]);
+        int16_t diff = a - b;
+        res += diff * diff;
+    }
+    return float(res);
+}
+
+float INT8_L2Sqr_LittleEndian(const void *pVect1v, const void *pVect2v, size_t dimension) {
+    return INT8_L2Sqr<true>(pVect1v, pVect2v, dimension);
+}
+
+float INT8_L2Sqr_BigEndian(const void *pVect1v, const void *pVect2v, size_t dimension) {
+    return INT8_L2Sqr<false>(pVect1v, pVect2v, dimension);
+}

src/VecSim/types/int8.h

@@ -0,0 +1,39 @@
+/*
+ *Copyright Redis Ltd. 2021 - present
+ *Licensed under your choice of the Redis Source Available License 2.0 (RSALv2) or
+ *the Server Side Public License v1 (SSPLv1).
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <cstring>
+#include <cmath>
+
+namespace vecsim_types {
+struct bfloat16 {
+    uint16_t val;
+    bfloat16() = default;
+    explicit constexpr bfloat16(uint16_t val) : val(val) {}
+    operator uint16_t() const { return val; }
+};
+
+static inline bfloat16 float_to_bf16(const float ff) {
+    uint32_t *p_f32 = (uint32_t *)&ff;
+    uint32_t f32 = *p_f32;
+    uint32_t lsb = (f32 >> 16) & 1;
+    uint32_t round = lsb + 0x7FFF;
+    f32 += round;
+    return bfloat16(f32 >> 16);
+}
+
+template <bool is_little = true>
+inline float bfloat16_to_float32(bfloat16 val) {
+    size_t constexpr bytes_offset = is_little ? 1 : 0;
+    float result = 0;
+    bfloat16 *p_result = (bfloat16 *)&result + bytes_offset;
+    *p_result = val;
+    return result;
+}
+
+} // namespace vecsim_types