Struct HNSWNode 

pub struct HNSWNode {
    pub id: u32,
    pub level: u8,
    pub neighbor_counts: [u8; 8],
    /* private fields */
}

HNSW node with cache-optimized layout

Hot data (first 64 bytes = 1 cache line):

• Node ID (4 bytes)
• Level (1 byte)
• Neighbor counts per level (8 bytes for 8 levels max)
• Padding to 64 bytes

Cold data stored separately:

• Neighbors (only fetched when traversing)
• Vector data (only fetched when computing distances)

Fields

id: u32

Node ID (u32 = 4 bytes, supports 4 billion vectors)

level: u8

Current level (0 to max_level)

neighbor_counts: [u8; 8]

Neighbor counts per level (u8 = 1 byte per level, max 8 levels)

neighbor_counts[i] = number of neighbors at level i

Implementations

impl HNSWNode

pub fn new(id: u32, level: u8) -> Self

Create a new node

pub fn neighbor_count(&self, level: u8) -> usize

Get number of neighbors at a given level

pub fn set_neighbor_count(&mut self, level: u8, count: usize)

Set number of neighbors at a given level

Note: Allows setting neighbor counts at ANY level, not just levels <= node.level. This is necessary because bidirectional edges can create connections at layers higher than the node’s originally assigned level.

Trait Implementations

impl Clone for HNSWNode

fn clone(&self) -> HNSWNode

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for HNSWNode

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

Formats the value using the given formatter.

impl Default for HNSWNode

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for HNSWNode

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for HNSWNode

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

where __S: Serializer,

Serialize this value into the given Serde serializer.