ml-nearest-vector/lib-es6/index.js

Find the nearest point to a sample point

'use strict';
import { squaredEuclidean } from 'ml-distance-euclidean';
const defaultOptions = {
    distanceFunction: squaredEuclidean
};
export default function nearestVector(listVectors, vector, options = defaultOptions) {
    const distanceFunction = options.distanceFunction || defaultOptions.distanceFunction;
    const similarityFunction = options.similarityFunction || defaultOptions.similarityFunction;
    let vectorIndex = -1;
    if (typeof similarityFunction === 'function') {
        // maximum similarity
        let maxSim = Number.MIN_VALUE;
        for (let j = 0; j < listVectors.length; j++) {
            const sim = similarityFunction(vector, listVectors[j]);
            if (sim > maxSim) {
                maxSim = sim;
                vectorIndex = j;
            }
        }
    }
    else if (typeof distanceFunction === 'function') {
        // minimum distance
        let minDist = Number.MAX_VALUE;
        for (let i = 0; i < listVectors.length; i++) {
            const dist = distanceFunction(vector, listVectors[i]);
            if (dist < minDist) {
                minDist = dist;
                vectorIndex = i;
            }
        }
    }
    else {
        throw new Error("A similarity or distance function it's required");
    }
    return vectorIndex;
}
export function findNearestVector(vectorList, vector, options = defaultOptions) {
    const index = nearestVector(vectorList, vector, options);
    return vectorList[index];
}