Enum DistanceMetric 

#[repr(u8)]
pub enum DistanceMetric {
    Cosine = 0,
    DotProduct = 1,
    L2 = 2,
}

Distance metric for vector similarity.

The #[repr(u8)] and explicit discriminants pin the on-disk byte encoding used by HNSW and quantized-vector segment blobs. Adding a new variant requires picking the next unused discriminant and updating Self::from_byte in the same change. See [[code-must-not-lie]].

Variants

Cosine = 0

Cosine distance: 1 - cosine_similarity. Lower = more similar.

DotProduct = 1

Negative dot product. Lower = more similar (for pre-normalized vectors).

L2 = 2

Euclidean (L2) distance. Lower = more similar.

Implementations

impl DistanceMetric

pub fn from_byte(byte: u8) -> Self

Decode a metric byte written by metric as u8. Panics on unknown bytes — these mean the segment is corrupted or was written by a newer Luci version with an unfamiliar metric. Silently mapping unknown bytes to a default (e.g., L2) would produce wrong recall and scoring without any signal to the caller.

Trait Implementations

impl Clone for DistanceMetric

fn clone(&self) -> DistanceMetric

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for DistanceMetric

impl Debug for DistanceMetric

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

Formats the value using the given formatter.

impl Eq for DistanceMetric

impl PartialEq for DistanceMetric

fn eq(&self, other: &DistanceMetric) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for DistanceMetric