fn from_float()

in candle-core/src/quantized/k_quants.rs [1252:1311]
51 lines of code
12 McCabe index (conditional complexity)

    fn from_float(xs: &[f32], ys: &mut [Self]) -> Result<()> {
        for (block, x) in group_for_quantization(xs, ys)? {
            let mut mins: [f32; QK_K / 32] = [0.0; QK_K / 32];
            let mut scales: [f32; QK_K / 32] = [0.0; QK_K / 32];

            for (j, x_scale_slice) in x.chunks_exact(32).enumerate() {
                (scales[j], mins[j]) = make_qkx1_quants(15, 5, x_scale_slice);
            }

            // get max scale and max min and ensure they are >= 0.0
            let max_scale = scales.iter().fold(0.0, |max, &val| val.max(max));
            let max_min = mins.iter().fold(0.0, |max, &val| val.max(max));

            let inv_scale = if max_scale > 0.0 {
                63.0 / max_scale
            } else {
                0.0
            };
            let inv_min = if max_min > 0.0 { 63.0 / max_min } else { 0.0 };

            for j in 0..QK_K / 32 {
                let ls = nearest_int(inv_scale * scales[j]).min(63) as u8;
                let lm = nearest_int(inv_min * mins[j]).min(63) as u8;
                if j < 4 {
                    block.scales[j] = ls;
                    block.scales[j + 4] = lm;
                } else {
                    block.scales[j + 4] = (ls & 0xF) | ((lm & 0xF) << 4);
                    block.scales[j - 4] |= (ls >> 4) << 6;
                    block.scales[j] |= (lm >> 4) << 6;
                }
            }

            block.d = f16::from_f32(max_scale / 63.0);
            block.dmin = f16::from_f32(max_min / 63.0);

            let mut l: [u8; QK_K] = [0; QK_K];

            for j in 0..QK_K / 32 {
                let (sc, m) = get_scale_min_k4(j, &block.scales);
                let d = block.d.to_f32() * sc as f32;
                if d != 0.0 {
                    let dm = block.dmin.to_f32() * m as f32;
                    for ii in 0..32 {
                        let l_val = nearest_int((x[32 * j + ii] + dm) / d);
                        l[32 * j + ii] = l_val.clamp(0, 15) as u8;
                    }
                }
            }

            let q = &mut block.qs;
            for j in (0..QK_K).step_by(64) {
                for l_val in 0..32 {
                    let offset_index = (j / 64) * 32 + l_val;
                    q[offset_index] = l[j + l_val] | (l[j + l_val + 32] << 4);
                }
            }
        }
        Ok(())
    }