Enum DistanceMetric 

pub enum DistanceMetric {
    Cosine,
    L2,
    InnerProduct,
}

Distance metric for vector similarity calculations.

Each metric has a corresponding pgvector operator:

• Cosine: <=> (most common for text embeddings)
• L2: <-> (Euclidean distance)
• InnerProduct: <#> (dot product, negate for similarity)

Variants

Cosine

Cosine distance (1 - cosine similarity). Best for normalized embeddings (OpenAI, most text embeddings). Operator: <=>

L2

L2 (Euclidean) distance. Good for image embeddings and when magnitude matters. Operator: <->

InnerProduct

Inner product (negative for similarity). Use when embeddings are already normalized and you want max inner product. Operator: <#>

Implementations

impl DistanceMetric

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

Get the pgvector operator for this distance metric.

pub const fn hnsw_ops_class(&self) -> &'static str

Get the HNSW index operator class.

pub const fn ivfflat_ops_class(&self) -> &'static str

Get the IVFFlat index operator class.

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 Default for DistanceMetric

fn default() -> DistanceMetric

Returns the “default value” for a type.

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 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