Module distance 

Distance computation for multi-vector representations.

The fallback path uses a double-loop kernel over InnerProduct; the factory returns cache-tiled SIMD kernels selected by MaxSimIsa.

Example

use diskann_quantization::multi_vector::{
    distance::{Chamfer, MaxSim, QueryMatRef},
    MatRef, Standard,
};
use diskann_vector::{DistanceFunctionMut, PureDistanceFunction};

// Query: 2 vectors of dim 3 (wrapped as QueryMatRef)
let query_data = [1.0f32, 0.0, 0.0, 0.0, 1.0, 0.0];
let query: QueryMatRef<_> = MatRef::new(
    Standard::new(2, 3).unwrap(),
    &query_data,
).unwrap().into();

// Doc: 2 vectors of dim 3
let doc_data = [1.0f32, 0.0, 0.0, 0.0, 0.0, 1.0];
let doc = MatRef::new(
    Standard::new(2, 3).unwrap(),
    &doc_data,
).unwrap();

// Chamfer distance (sum of max similarities)
let chamfer_dist = Chamfer::evaluate(query, doc);

// MaxSim (per-query-vector scores)
let mut scores = vec![0.0f32; 2];
let mut max_sim = MaxSim::new(&mut scores);
max_sim.evaluate(query, doc);
// scores[0] = -1.0 (query[0] matches doc[0]: negated max inner product)
// scores[1] =  0.0 (query[1] has no good match: max IP was 0)

Structs

BoxErase

Default boxing Erase impl.

Chamfer

Asymmetric Chamfer distance for multi-vector similarity.

MaxSim

Computes per-query-vector maximum similarities to document vectors.

NotSupported

Returned by build_max_sim when the requested ISA cannot be produced on the current host (e.g. x86_64 V4 requested on a non-AVX512 CPU, or Neon requested on x86_64).

QueryMatRef

A query matrix view for asymmetric distance functions.

Enums

MaxSimError

Error type for MaxSim operations.

MaxSimIsa

Instruction Set Architecture (ISA) selector for which multi-vector MaxSim kernel to build.

Traits

Erase

“Bring your own type erasure” visitor: the factory hands a concrete kernel to Erase::erase, which decides how to package it (e.g. as Box<dyn MaxSimKernel<T>> via BoxErase, a chamfer-only closure, a batched evaluator, …).

MaxSimElement

Scalar element types accepted by build_max_sim.

MaxSimKernel

Object-safe interface for computing per-query MaxSim scores.

Functions

build_max_sim

Build a multi-vector MaxSim kernel for any MaxSimElement type.