@thi.ng/distance/radial.js

N-dimensional distance metrics & K-nearest neighborhoods for point queries

import { clamp0 } from "@thi.ng/math/interval";
import { DIST_SQ, DIST_SQ1, DIST_SQ2, DIST_SQ3 } from "./squared.js";
class Radial {
  constructor(dist, target, radius = Infinity) {
    this.dist = dist;
    this.target = target;
    this.radius = radius;
    this.setRadius(radius);
  }
  _r;
  _items;
  /**
   * Clears current results.
   */
  reset() {
    this._items = [];
    return this;
  }
  /**
   * Resets search/reference position and clears current results.
   *
   * @param target
   */
  setTarget(target) {
    this.target = target;
    this.reset();
  }
  /**
   * Resets search/query radius and clears current results.
   *
   * @param r
   */
  setRadius(r) {
    this.radius = clamp0(r);
    this._r = this.dist.to(this.radius);
    this.reset();
  }
  /**
   * Returns an array of current neighbor result tuples (each `[dist, val]`).
   *
   * @remarks
   * Use {@link Radial.values} to obtain result values **without** their
   * distance metrics.
   */
  deref() {
    return this._items;
  }
  /**
   * Similar to {@link Radial.deref}, but returns array of result values **without**
   * their distance metrics.
   */
  values() {
    return this._items.map((x) => x[1]);
  }
  includesDistance(d, eucledian = true) {
    return (eucledian ? this.dist.to(d) : d) <= this._r;
  }
  includesPosition(pos) {
    return this.dist.metric(this.target, pos) < this._r;
  }
  consider(pos, val) {
    const d = this.dist.metric(this.target, pos);
    if (d <= this._r) {
      this._items.push([d, val]);
    }
    return d;
  }
}
const radial = (p, r, dist = DIST_SQ) => new Radial(dist, p, r);
const radial2 = (p, r, dist = DIST_SQ2) => new Radial(dist, p, r);
const radial3 = (p, r, dist = DIST_SQ3) => new Radial(dist, p, r);
const radialN = (p, r, dist = DIST_SQ1) => new Radial(dist, p, r);
export {
  Radial,
  radial,
  radial2,
  radial3,
  radialN
};