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Fix kdtree implementation.
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2 changed files with 162 additions and 29 deletions
302
vendor/kdtree/core.js
vendored
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302
vendor/kdtree/core.js
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/**
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* kdtree
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*
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* Is a modified and google closure adapted kdtree implementation
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* of https://github.com/ubilabs/kd-tree-javascript.
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*
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* @author Andrey Antukh <niwi@niwi.nz>, 2016
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* @author Mircea Pricop <pricop@ubilabs.net>, 2012
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* @author Martin Kleppe <kleppe@ubilabs.net>, 2012
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* @author Ubilabs http://ubilabs.net, 2012
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* @license MIT License <https://opensource.org/licenses/MIT>
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*/
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goog.provide("kdtree.core");
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goog.provide("kdtree.core.KDTree");
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goog.require("kdtree.heap");
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goog.require("goog.array");
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goog.require("goog.asserts");
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goog.scope(function() {
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"use strict";
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const assert = goog.asserts.assert;
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const assertNumber = goog.asserts.assertNumber;
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const every = goog.array.every;
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class Node {
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constructor(obj, dimension, parent) {
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this.obj = obj;
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this.left = null;
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this.right = null;
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this.parent = parent;
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this.dimension = dimension;
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}
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}
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function precision(v) {
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return parseFloat(v.toFixed(6));
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}
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function buildTree(points, depth, parent, dimensions) {
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const dim = depth % dimensions;
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if (points.length === 0) {
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return null;
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}
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if (points.length === 1) {
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return new Node(points[0], dim, parent);
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}
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points.sort((a, b) => {
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return a[dim] - b[dim];
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});
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const median = Math.floor(points.length / 2);
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const node = new Node(points[median], dim, parent);
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node.left = buildTree(points.slice(0, median), depth + 1, node, dimensions);
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node.right = buildTree(points.slice(median + 1), depth + 1, node, dimensions);
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return node;
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}
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function findMin(node, dim) {
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let dimension, own, left, right, min;
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if (node === null) {
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return null;
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}
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if (node.dimension === dim) {
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if (node.left !== null) {
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return findMin(node.left, dim);
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}
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return node;
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}
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own = node.obj[dim];
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left = findMin(node.left, dim);
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right = findMin(node.right, dim);
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min = node;
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if (left !== null && left.obj[dim] < own) {
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min = left;
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}
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if (right !== null && right.obj[dim] < min.obj[dim]) {
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min = right;
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}
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return min;
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}
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function innerSearch(point, node, parent) {
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if (node === null) {
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return parent;
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}
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if (point[dim] < node.obj[dim]) {
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return innerSearch(point, node.left, node);
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} else {
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return innerSearch(point, node.right, node);
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}
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}
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function nodeSearch(point, node) {
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if (node === null) {
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return null;
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}
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if (node.obj === point) {
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return node;
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}
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if (point[node.dimension] < node.obj[node.dimension]) {
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return nodeSearch(point, node.left);
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} else {
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return nodeSearch(point, node.right);
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}
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}
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class KDTree {
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constructor(points, metric, dimensions) {
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assert(points.length !== 0);
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assertNumber(dimensions);
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this.root = buildTree(points, 0, null, dimensions);
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this.metric = metric;
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this.dimensions = dimensions;
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}
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insert(point) {
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const insertPosition = innerSearch(point, this.root, null);
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if (insertPosition === null) {
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this.root = new Node(point, 0, null);
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return;
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}
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const newNode = new Node(point,
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(insertPosition.dimension + 1) % this.dimensions,
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insertPosition);
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const dimension = insertPosition.dimension;
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if (point[dimension] < insertPosition.obj[dimension]) {
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insertPosition.left = newNode;
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} else {
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insertPosition.right = newNode;
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}
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}
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remove(point) {
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const node = nodeSearch(point, this.root);
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if (node === null) {
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return;
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}
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if (node.left === null && node.right === null) {
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if (node.parent === null) {
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this.root = null;
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return;
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}
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const pdim = node.parent.dimension;
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if (node.obj[pdim] < node.parent.obj[pdim]) {
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node.parent.left = null;
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} else {
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node.parent.right = null;
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}
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return;
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}
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// If the right subtree is not empty, swap with the minimum element on the
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// node's dimension. If it is empty, we swap the left and right subtrees and
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// do the same.
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let nextNode, nextObj;
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if (node.right !== null) {
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nextNode = findMin(node.right, node.dimension);
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nextObj = nextNode.obj;
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removeNode(nextNode);
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node.obj = nextObj;
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} else {
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nextNode = findMin(node.left, node.dimension);
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nextObj = nextNode.obj;
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removeNode(nextNode);
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node.right = node.left;
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node.left = null;
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node.obj = nextObj;
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}
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}
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nearest(point, maxNodes) {
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if (maxNodes === undefined) {
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maxNodes = 1;
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}
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let best = new kdtree.heap.MinHeap((x, y) => {
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let res = x[1] - y[1];
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return res;
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});
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const nearestSearch = (node) => {
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let distance = precision(this.metric(point, node.obj));
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if (best.isEmpty()) {
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best.insert([node.obj, distance]);
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} else {
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if (distance < best.peek()[1]) {
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best.insert([node.obj, distance]);
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}
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}
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if (node.right === null && node.left === null) {
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return;
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}
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let bestChild = null;
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if (node.right === null) {
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bestChild = node.left;
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} else if (node.left === null) {
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bestChild = node.right;
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} else {
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if (point[node.dimension] < node.obj[node.dimension]) {
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bestChild = node.left;
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} else {
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bestChild = node.right;
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}
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}
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nearestSearch(bestChild);
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let candidate = [null, null];
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for (let i = 0; i < this.dimensions; i += 1) {
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if (i === node.dimension) {
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candidate[i] = point[i];
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} else {
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candidate[i] = node.obj[i];
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}
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}
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distance = Math.abs(this.metric(candidate, node.obj));
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if (best.size < maxNodes || distance < best.peek()[1]) {
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let otherChild;
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if (bestChild === node.left) {
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otherChild = node.right;
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} else {
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otherChild = node.left;
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}
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if (otherChild !== null) {
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nearestSearch(otherChild);
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}
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}
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}
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if(this.root) {
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nearestSearch(this.root);
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}
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const result = [];
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for (let i=0; i < (Math.min(maxNodes, best.size)); i++) {
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result.push(best.removeHead());
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}
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return result;
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}
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balanceFactor() {
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function height(node) {
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if (node === null) {
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return 0;
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}
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return Math.max(height(node.left), height(node.right)) + 1;
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}
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function count(node) {
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if (node === null) {
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return 0;
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}
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return count(node.left) + count(node.right) + 1;
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}
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return height(this.root) / (Math.log(count(this.root)) / Math.log(2));
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}
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}
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function distance2d(a, b){
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return Math.sqrt(Math.pow(a[0] - b[0], 2) + Math.pow(a[1] - b[1], 2));
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}
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function create2d(points) {
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return new KDTree(points, distance2d, 2);
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};
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// Types
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kdtree.core.KDTree = KDTree;
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// Factory functions
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kdtree.core.create2d = create2d;
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});
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