Struct PQScratch 

pub struct PQScratch {
    pub aligned_pqtable_dist_scratch: AlignedSlice<f32>,
    pub aligned_dist_scratch: AlignedSlice<f32>,
    pub aligned_pq_coord_scratch: AlignedSlice<u8>,
    pub rotated_query: Vec<f32>,
}

PQ scratch

Fields

aligned_pqtable_dist_scratch: AlignedSlice<f32>

Aligned pq table distance scratch, the length must be at least [256 * NCHUNKS]. 256 is the number of PQ centroids. This is used to store the distance between each chunk in the query vector to each centroid, which is why the length is num of centroids * num of chunks

aligned_dist_scratch: AlignedSlice<f32>

Aligned dist scratch, must be at least diskann MAX_DEGREE This is used to temporarily save the pq distance between query vector to the candidate vectors.

aligned_pq_coord_scratch: AlignedSlice<u8>

Aligned pq coord scratch, must be at least [N_CHUNKS * MAX_DEGREE] This is used to store the pq coordinates of the candidate vectors.

rotated_query: Vec<f32>

Query scratch buffer stored as f32. set initializes it by copying/converting the raw query values; PQTable.PreprocessQuery can then rotate or otherwise preprocess it.

Implementations

impl PQScratch

pub fn new( graph_degree: usize, dim: usize, num_pq_chunks: usize, num_centers: usize, ) -> ANNResult<Self>

Create a new pq scratch

pub fn set<T: VectorRepr>(&mut self, dim: usize, query: &[T]) -> ANNResult<()>

Copy query into rotated_query, converting to f32.

dim is the element count in the T representation. The decompressed f32 length returned by T::as_f32 may differ (e.g. MinMaxElement expands to more f32s than its raw element count), so the destination slice is sized by that actual length.

Returns DimensionMismatchError if dim > query.len() or the decompressed vector does not fit in rotated_query.

Trait Implementations

impl Debug for PQScratch

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

Formats the value using the given formatter.