k-medoids/dist/Clusterer/cluster.js

Implementation of the k-mediods clustering algorithm

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
class Cluster {
    constructor(cluster) {
        this.getCost = () => {
            return this.Elements.map((e) => e.DistanceFromMedoid).reduce((a, b) => a + b, 0);
        };
        this.findBestMedoidIdx = (distanceFn) => {
            const mapToCost = (e) => this.calcCostForGivenElementAsMedoid(e, distanceFn);
            const candidateNewMedoids = this.Elements
                .map(mapToCost);
            return candidateNewMedoids
                .reduce((iMin, e, idx, arr) => e.CostIfMadeMedoid < arr[iMin].CostIfMadeMedoid ? idx : iMin, 0);
        };
        this.calcCostForGivenElementAsMedoid = (proposedMedoid, distanceFn) => {
            const clusterWithThisAsMedoid = new Cluster({
                Elements: this.Elements.map((elem) => {
                    const ret = {
                        DistanceFromMedoid: distanceFn(elem.Element, proposedMedoid.Element),
                        Element: elem.Element,
                    };
                    return ret;
                }),
                Medoid: proposedMedoid.Element,
            });
            return {
                CostIfMadeMedoid: clusterWithThisAsMedoid.getCost(),
                Element: proposedMedoid,
            };
        };
        this.Elements = cluster.Elements;
        this.Medoid = cluster.Medoid;
    }
}
exports.Cluster = Cluster;