Enum DistanceMetric 

#[non_exhaustive]
pub enum DistanceMetric {
    L2,
    InnerProduct,
    Cosine,
    L1,
}

Vector distance metric supported by pgvector.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

L2

Euclidean distance (L2 norm).

Operator: <-> Range: [0, ∞) Use when: comparing absolute distances between vectors.

InnerProduct

Negative inner product.

Operator: <#> Range: (-∞, ∞) Use when: vectors are normalized and you want maximum inner product.

Note: pgvector returns negative inner product so that smaller = more similar, consistent with the ORDER BY ASC convention.

Cosine

Cosine distance (1 - cosine similarity).

Operator: <=> Range: [0, 2] Use when: comparing direction regardless of magnitude.

L1

Manhattan distance (L1 norm).

Operator: <+> Range: [0, ∞) Use when: you need L1 distance, often in recommendation systems.

Implementations

impl DistanceMetric

pub fn operator(&self) -> &'static str

Get the PostgreSQL operator for this metric.

pub fn ops_class(&self) -> &'static str

Get the operator class name for index creation.

pub fn name(&self) -> &'static str

Get a human-readable name for this metric.

pub fn prefers_normalized(&self) -> bool

Whether this metric benefits from normalized vectors.

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 Debug for DistanceMetric

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for DistanceMetric

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for DistanceMetric

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

Formats the value using the given formatter.

impl Hash for DistanceMetric

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

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 Serialize for DistanceMetric

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for DistanceMetric

impl Eq for DistanceMetric

impl StructuralPartialEq for DistanceMetric