Struct HnswConfigBuilder 

pub struct HnswConfigBuilder {
    pub config: HnswConfig,
}

Builder pattern for HnswConfig construction

Provides a fluent interface for creating HnswConfig instances with validation and sensible defaults.

Examples

use sqlitegraph::hnsw::{HnswConfig, DistanceMetric};

// Single-layer configuration (default, backward compatible)
let config = HnswConfigBuilder::new()
    .dimension(512)
    .m_connections(24)
    .ef_construction(300)
    .ef_search(80)
    .max_layers(20)
    .distance_metric(DistanceMetric::Euclidean)
    .build()
    .unwrap();

// Multi-layer configuration for large datasets
let multilayer_config = HnswConfigBuilder::new()
    .dimension(768)
    .m_connections(16)
    .ef_construction(200)
    .ef_search(50)
    .max_layers(16)
    .distance_metric(DistanceMetric::Cosine)
    .enable_multilayer(true)
    .multilayer_level_distribution_base(Some(16))
    .multilayer_deterministic_seed(Some(42))
    .build()
    .unwrap();

Fields

config: HnswConfig

Implementations

impl HnswConfigBuilder

pub fn new() -> Self

Create a new builder with default configuration

pub fn dimension(self, dimension: usize) -> Self

Set vector dimension count

Arguments

• dimension - Number of dimensions in vectors (1-4096)

Panics

Panics if dimension is 0 or exceeds practical limits (>4096)

pub fn m_connections(self, m: usize) -> Self

Set number of connections per node (M parameter)

Arguments

• m - Number of connections (5-48 typical)

Panics

Panics if m is 0 or exceeds practical limits (>48)

pub fn ef_construction(self, ef: usize) -> Self

Set construction ef parameter

Arguments

• ef - Construction ef value (100-800 typical)

Panics

Panics if ef is less than m (must be >= M for proper construction)

pub fn ef_search(self, ef: usize) -> Self

Set search ef parameter

Arguments

• ef - Search ef value (10-200 typical)

Panics

Panics if ef is 0 or exceeds practical limits (>200)

pub fn max_layers(self, ml: u8) -> Self

Set maximum number of layers

Arguments

• ml - Maximum layer count (8-32 typical)

Panics

Panics if ml is 0 or exceeds practical limits (>32)

pub fn distance_metric(self, metric: DistanceMetric) -> Self

Set distance metric

Arguments

• metric - Distance metric to use

pub fn enable_multilayer(self, enable: bool) -> Self

Enable multi-layer HNSW functionality

When enabled, uses proper multi-layer HNSW with exponential distribution. When disabled, uses single-layer mode for backward compatibility.

Arguments

• enable - Whether to enable multi-layer functionality

pub fn multilayer_level_distribution_base(self, base: Option<usize>) -> Self

Set base value for exponential level distribution in multi-layer mode

Higher values create flatter layer distributions (more vectors in higher layers). When None, uses the m parameter value as default.

Arguments

• base - Base value for level distribution, or None to use m

pub fn multilayer_deterministic_seed(self, seed: Option<u64>) -> Self

Set deterministic seed for multi-layer operations

When provided, ensures reproducible level assignments across runs. When None, uses non-deterministic behavior (default for production).

Arguments

• seed - Seed value, or None for non-deterministic behavior

pub fn build(self) -> Result<HnswConfig, HnswConfigError>

Build the HnswConfig with validation

Returns

Returns Ok(HnswConfig) if all parameters are valid, or Err(HnswConfigError) if validation fails.

Errors

• InvalidDimension if dimension is 0
• InvalidMParameter if m is 0
• InvalidEfConstruction if ef_construction < m
• InvalidEfSearch if ef_search is 0
• InvalidMaxLayers if ml is 0

Examples

use sqlitegraph::hnsw::{HnswConfigBuilder, DistanceMetric};

let config = HnswConfigBuilder::new()
    .dimension(256)
    .distance_metric(DistanceMetric::Cosine)
    .build()
    .unwrap();

Trait Implementations

impl Default for HnswConfigBuilder

fn default() -> Self

Returns the “default value” for a type.