jkrukowski/swift-hnsw

Installation

Add the dependency to your Package.swift:

dependencies: [
    .package(url: "https://github.com/jkrukowski/swift-hnsw.git", from: "0.0.1")
]

Usage

Basic Example

import HNSW

// Create an index for 4-dimensional vectors
let index = try Index(4)

// Insert vectors with optional custom IDs
try index.insert([1.0, 0.0, 0.0, 0.0], nodeId: 1)
try index.insert([0.0, 1.0, 0.0, 0.0], nodeId: 2)
try index.insert([0.9, 0.1, 0.0, 0.0], nodeId: 3)

// Search for nearest neighbors
let results = index.search([1.0, 0.0, 0.0, 0.0], k: 3)
for result in results {
    print("Node ID: \(result.node.id), Distance: \(result.distance)")
}

Quantization

Reduce memory usage with vector quantization:

// 8-bit quantization
let indexQ8 = try Index(4, quantization: .q8)

// Binary quantization
let indexBinary = try Index(4, quantization: .binary)

Serialization

Save and load indexes:

// Serialize index to bytes
let data = try index.serialize()

// Deserialize from bytes
let loadedIndex = try Index.deserialize(from: data)

Node Management

// Delete a node
try index.delete(node)

// Get node count
print("Total nodes: \(index.nodeCount)")

// Iterate over all nodes
for node in index.nodes() {
    let vector = index.vector(of: node)
    print("Node \(node.id): \(vector)")
}

// Calculate distance between nodes
let distance = index.distance(from: node1, to: node2)

Acknowledgements

This project uses HNSW implementation taken from Redis originally authored by Salvatore Sanfilippo.

Code Formatting

This project uses swift-format. To format the code run:

swift format . -i -r --configuration .swift-format

Package Metadata

Repository: jkrukowski/swift-hnsw

Default branch: main

README: README.md