Examples

Rust example [more info (opens new window)]

use hora::core::ann_index::ANNIndex;
use rand::{thread_rng, Rng};
use rand_distr::{Distribution, Normal};

pub fn demo() {
    let n = 1000;
    let dimension = 64;

    // make sample points
    let mut samples = Vec::with_capacity(n);
    let normal = Normal::new(0.0, 10.0).unwrap();
    for _i in 0..n {
        let mut sample = Vec::with_capacity(dimension);
        for _j in 0..dimension {
            sample.push(normal.sample(&mut rand::thread_rng()));
        }
        samples.push(sample);
    }

    // init index
    let mut index = hora::index::hnsw_idx::HNSWIndex::<f32, usize>::new(
        dimension,
        &hora::index::hnsw_params::HNSWParams::<f32>::default(),
    );
    for (i, sample) in samples.iter().enumerate().take(n) {
        // add point
        index.add(sample, i).unwrap();
    }
    index.build(hora::core::metrics::Metric::Euclidean).unwrap();

    let mut rng = thread_rng();
    let target: usize = rng.gen_range(0..n);
    // 523 has neighbors: [523, 762, 364, 268, 561, 231, 380, 817, 331, 246]
    println!(
        "{:?} has neighbors: {:?}",
        target,
        index.search(&samples[target], 10) // search for k nearest neighbors
    );
}

Python exmaple [more info (opens new window)]

import numpy as np
from horapy import HNSWIndex

dimension = 50
n = 1000

# init index instance
index = HNSWIndex(dimension, "usize")

samples = np.float32(np.random.rand(n, dimension))
for i in range(0, len(samples)):
    # add node
    index.add(np.float32(samples[i]), i)

index.build("euclidean")  # build index

target = np.random.randint(0, n)
# 410 in Hora ANNIndex <HNSWIndexUsize> (dimension: 50, dtype: usize, max_item: 1000000, n_neigh: 32, n_neigh0: 64, ef_build: 20, ef_search: 500, has_deletion: False)
# has neighbors: [410, 736, 65, 36, 631, 83, 111, 254, 990, 161]
print("{} in {} \nhas neighbors: {}".format(
    target, index, index.search(samples[target], 10)))  # search

Javascript example [more info (opens new window)]

const demo = () => {
  const dimension = 50;

  var bf_idx = hora_wasm.BruteForceIndexUsize.new(dimension);
  for (var i = 0; i < 1000; i++) {
    var feature = [];
    for (var j = 0; j < dimension; j++) {
      feature.push(Math.random());
    }
    bf_idx.add(feature, i); // add point 
  }
  bf_idx.build("euclidean"); // build index
  var feature = [];
  for (var j = 0; j < dimension; j++) {
    feature.push(Math.random());
  }
  console.log("bf result",  .search(feature, 10)); //bf result Uint32Array(10) [704, 113, 358, 835, 408, 379, 117, 414, 808, 826]
}

Java examples [more info (opens new window)]

public void demo() {
    final int dimension = 2;
    final float variance = 2.0f;
    Random fRandom = new Random();

    BruteForceIndex bruteforce_idx = new BruteForceIndex(dimension); // init index instance

    List<float[]> tmp = new ArrayList<>();
    for (int i = 0; i < 5; i++) {
        for (int p = 0; p < 10; p++) {
            float[] features = new float[dimension];
            for (int j = 0; j < dimension; j++) {
                features[j] = getGaussian(fRandom, (float) (i * 10), variance);
            }
            bruteforce_idx.add("bf", features, i * 10 + p); // add point
            tmp.add(features);
          }
    }
    bruteforce_idx.build("bf", "euclidean"); // build index

    int search_index = fRandom.nextInt(tmp.size());
    // nearest neighbor search
    int[] result = bruteforce_idx.search("bf", 10, tmp.get(search_index)); 
    // [main] INFO com.hora.app.ANNIndexTest  - demo bruteforce_idx[7, 8, 0, 5, 3, 9, 1, 6, 4, 2]
    log.info("demo bruteforce_idx" + Arrays.toString(result)); 
}

private static float getGaussian(Random fRandom, float aMean, float variance) {
    float r = (float) fRandom.nextGaussian();
    return aMean + r * variance;
}