František Špaček
1 year ago
parent
11e4a67708
commit
a71e01cca7
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/**
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* Calculates the Euclidean distance between two points in n-dimensional space.
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*
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* @param {number[]} a - The first point, represented as an array of numbers.
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* @param {number[]} b - The second point, represented as an array of numbers.
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* @returns {number} The Euclidean distance between the two points.
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*/
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function euclideanDistance(a, b) {
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return Math.sqrt(a.reduce((acc, val, i) => acc + (val - b[i]) ** 2, 0));
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}
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/**
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* Calculates the Manhattan distance (L1) between two points in n-dimensional space.
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*
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* @param {number[]} a - The first point, represented as an array of numbers.
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* @param {number[]} b - The second point, represented as an array of numbers.
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* @returns {number} The Manhattan distance between the two points.
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*/
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function manhattanDistance(a, b) {
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return a.reduce((acc, val, i) => acc + Math.abs(val - b[i]), 0);
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}
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/**
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* Calculates the Maximum distance (L∞) between two points in n-dimensional space.
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*
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* @param {number[]} a - The first point, represented as an array of numbers.
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* @param {number[]} b - The second point, represented as an array of numbers.
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* @returns {number} The Maximum distance between the two points.
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*/
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function maximumDistance(a, b) {
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return Math.max(...a.map((val, i) => Math.abs(val - b[i])));
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}
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/**
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* Calculates the Minkowski distance (Lp) between two points in n-dimensional space.
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*
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* @param {number[]} a - The first point, represented as an array of numbers.
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* @param {number[]} b - The second point, represented as an array of numbers.
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* @param {number} p - The order of the Minkowski distance.
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* @returns {number} The Minkowski distance between the two points.
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*/
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function minkowskiDistance(a, b, p) {
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return Math.pow(a.reduce((acc, val, i) => acc + Math.pow(Math.abs(val - b[i]), p), 0), 1 / p);
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}
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/**
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* Calculates the quadratic distance between two points in n-dimensional space.
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*
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* @param {number[]} a - The first point, represented as an array of numbers.
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* @param {number[]} b - The second point, represented as an array of numbers.
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* @returns {number} The quadratic distance between the two points.
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*/
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function quadraticDistance(a, b) {
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return a.reduce((acc, val, i) => acc + (val - b[i]) ** 2, 0);
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}
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/**
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* Calculates the angle between two points in n-dimensional space.
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*
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* @param {number[]} a - The first point, represented as an array of numbers.
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* @param {number[]} b - The second point, represented as an array of numbers.
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* @returns {number} The angle between the two points in radians.
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*/
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function angleDistance(a, b) {
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const dotProduct = a.reduce((acc, val, i) => acc + val * b[i], 0);
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const magnitudeA = Math.sqrt(a.reduce((acc, val) => acc + val ** 2, 0));
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const magnitudeB = Math.sqrt(b.reduce((acc, val) => acc + val ** 2, 0));
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return Math.acos(dotProduct / (magnitudeA * magnitudeB));
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}
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const distanceFunctions = {
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'euclidean': euclideanDistance,
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'manhattan': manhattanDistance,
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'maximum': maximumDistance,
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'minkowski': minkowskiDistance,
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'quadratic': quadraticDistance,
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'angle': angleDistance
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};
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//export { euclideanDistance, manhattanDistance, maximumDistance, minkowskiDistance, quadraticDistance, angleDistance };
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module.exports = distanceFunctions;
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@ -0,0 +1,29 @@
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/**
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* Calculates the centroid of an array of entries.
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* The centroid is the point that is the mean of all the points in the array.
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* The mean is calculated using the weight of each point, which defaults to 1.
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* @param {Object[]} entries - The array of entries to calculate the centroid from.
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* @param {function} [distanceFunction] - A distance function to use to calculate the weight of each point.
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* @returns {number[]} The centroid of the array of entries.
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*/
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function calculateCentroid(entries, distanceFunction) {
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if (entries.length === 0)
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return;
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const length = entries[0].point.length;
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const sum = new Array(length).fill(0);
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let totalWeight = 0;
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for (const entry of entries) {
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const weight = entry.radius || 1;
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//const weight = distanceFunction(entry.point, this.point);
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for (let i = 0; i < length; i++) {
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sum[i] += entry.point[i] * weight;
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}
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totalWeight += weight;
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}
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return sum.map(val => val / totalWeight);
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}
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module.exports = { calculateCentroid };
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