inline float euclidean_distance()

in src/annoylib.h [262:283]

• 20 lines of code
• 4 McCabe index (conditional complexity)

inline float euclidean_distance<float>(const float* x, const float* y, int f) {
  float result=0;
  if (f > 7) {
    __m256 d = _mm256_setzero_ps();
    for (; f > 7; f -= 8) {
      const __m256 diff = _mm256_sub_ps(_mm256_loadu_ps(x), _mm256_loadu_ps(y));
      d = _mm256_add_ps(d, _mm256_mul_ps(diff, diff)); // no support for fmadd in AVX...
      x += 8;
      y += 8;
    }
    // Sum all floats in dot register.
    result = hsum256_ps_avx(d);
  }
  // Don't forget the remaining values.
  for (; f > 0; f--) {
    float tmp = *x - *y;
    result += tmp * tmp;
    x++;
    y++;
  }
  return result;
}