Struct RandomProjectionHasher 

pub struct RandomProjectionHasher { /* private fields */ }

A random-projection hash family for one hash table.

Uses sign-of-random-projection (SimHash / hyperplane LSH) to map vectors to bit signatures. Each bit corresponds to the sign of the dot product with a random Gaussian vector.

Projections are stored as a (num_hashes x dim) matrix so that all dot products can be computed in a single matrix-vector multiply.

Implementations

impl RandomProjectionHasher

pub fn new(dim: usize, num_hashes: usize, rng: &mut impl Rng) -> Self

Create a new hasher with num_hashes random projection vectors of dimension dim.

pub fn hash_vector( &self, vector: &ArrayView1<'_, f32>, ) -> (u64, Vec<(usize, f32)>)

Compute the hash key for a vector, along with margin information for multi-probe.

Returns (hash_key, margins) where margins is a vec of (bit_index, |dot_product|) sorted by ascending margin (most uncertain bits first).

pub fn hash_vector_fast(&self, vector: &ArrayView1<'_, f32>) -> u64

Compute just the hash key (fast path, no margin data).

pub fn num_hashes(&self) -> usize

Number of hash functions (bits in the signature).

Trait Implementations

impl Clone for RandomProjectionHasher

fn clone(&self) -> RandomProjectionHasher

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RandomProjectionHasher

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

Formats the value using the given formatter.