normalize_inplace()

MAYAFLUX_API void MayaFlux::Kinesis::Vision::normalize_inplace

(

std::span< float >

data

)

Stretch values to fill [0, 1] using the span's observed min and max.

No-op if min == max. Operates in-place.

Parameters

data	Float span to normalise in-place.

Definition at line 353 of file PixelOps.cpp.

{
    if (data.empty())
        return;
 
    const Eigen::Index en = static_cast<Eigen::Index>(data.size());
    auto m = Eigen::Map<Eigen::ArrayXf>(data.data(), en);
    const float mn = m.minCoeff();
    const float mx = m.maxCoeff();
    const float range = mx - mn;
    if (range == 0.0F)
        return;
 
    const float inv = 1.0F / range;
    float* out = data.data();
    const size_t n = data.size();
 
#ifdef MAYAFLUX_ARCH_X64
    const __m256 v_mn = _mm256_set1_ps(mn);
    const __m256 v_inv = _mm256_set1_ps(inv);
    size_t i = 0;
    for (; i + 8 <= n; i += 8) {
        __m256 v = _mm256_loadu_ps(out + i);
        _mm256_storeu_ps(out + i, _mm256_mul_ps(_mm256_sub_ps(v, v_mn), v_inv));
    }
    for (; i < n; ++i)
        out[i] = (out[i] - mn) * inv;
 
#elif defined(MAYAFLUX_ARCH_ARM64)
    const float32x4_t v_mn = vdupq_n_f32(mn);
    const float32x4_t v_inv = vdupq_n_f32(inv);
    size_t i = 0;
    for (; i + 4 <= n; i += 4) {
        float32x4_t v = vld1q_f32(out + i);
        vst1q_f32(out + i, vmulq_f32(vsubq_f32(v, v_mn), v_inv));
    }
    for (; i < n; ++i)
        out[i] = (out[i] - mn) * inv;
 
#else
    P::transform(P::par_unseq, data.begin(), data.end(), data.begin(),
        [mn, inv](float v) { return (v - mn) * inv; });
#endif
}