Struct FastScanLUT 

pub struct FastScanLUT { /* private fields */ }

Quantized LUT for FastScan (u8 distances for SIMD efficiency)

Contains pre-computed distance contributions for each possible code value. For 4-bit quantization: 16 entries per sub-quantizer, separate LUTs for lo/hi nibbles.

Implementations

impl FastScanLUT

pub fn from_adc_table(adc: &ADCTable) -> Option<Self>

Build FastScan LUT from RaBitQ ADC table

ADC table format: table[dim][code] = partial squared distance For 4-bit quantization with D dimensions:

• D/2 sub-quantizers (each byte packs 2 dimensions)
• table[sq*2][code] = distance contribution for lo nibble (even dim)
• table[sq*2+1][code] = distance contribution for hi nibble (odd dim)

pub fn num_sq(&self) -> usize

Get number of sub-quantizers

pub fn luts_lo(&self) -> &[[u8; 16]]

Get lo nibble LUTs

pub fn luts_hi(&self) -> &[[u8; 16]]

Get hi nibble LUTs

pub fn to_f32(&self, accumulated: u16) -> f32

Convert accumulated u16 distance back to approximate f32

Trait Implementations

impl Clone for FastScanLUT

fn clone(&self) -> FastScanLUT

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FastScanLUT

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.