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chore: merge Fix/742 migrate doctest to jest (#749)
* Remove QuickSelect doctest There are more Jest test cases already. * Remove AverageMedian doctest Already migrated to jest * Migrate doctest for BinaryExponentiationRecursive.js (also remove inline "main" test method) * Migrate doctest for EulersTotient.js (also remove inline "main" test method) * Migrate doctest for PrimeFactors.js (also remove inline "main" test method) * Migrate doctest for BogoSort.js Re-write prototype-polluting helper methods, too. (also remove inline test driver code) * Migrate doctest for BeadSort.js (also remove inline test driver code) * Migrate doctest for BucketSort.js (also remove inline test driver code) * Migrate doctest for CocktailShakerSort.js (also remove inline test driver code) * Migrate doctest for MergeSort.js (also remove inline test driver code) * Migrate doctest for QuickSort.js (also remove inline test driver code) * Migrate doctest for ReverseString.js (also remove inline test driver code) * Migrate doctest for ReverseString.js * Migrate doctest for ValidateEmail.js * Migrate doctest for ConwaysGameOfLife.js (remove the animate code, too) * Remove TernarySearch doctest Already migrated to jest * Migrate doctest for BubbleSort.js (also remove inline test driver code) * Remove doctest from CI and from dependencies relates to #742 fixes #586 * Migrate doctest for RgbHsvConversion.js * Add --fix option to "standard" npm script * Migrate doctest for BreadthFirstSearch.js (also remove inline test driver code) * Migrate doctest for BreadthFirstShortestPath.js (also remove inline test driver code) * Migrate doctest for EulerMethod.js (also remove inline test driver code) Move manual test-code for plotting stuff in the browser in a distinct file, too. Those "*.manual-test.js" files are excluded from the UpdateDirectory.mjs script, as well. * Migrate doctest for Mandelbrot.js (also remove inline test driver code & moved manual drawing test into a *.manual-test.js) * Migrate doctest for FloodFill.js * Migrate doctest for KochSnowflake.js (also move manual drawing test into a *.manual-test.js) * Update npm lockfile * Update README and COMMITTING with a few bits & bobs regarding testing & code quality
This commit is contained in:
Roland Hummel
@ -1,28 +1,19 @@
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/*
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In mathematics and computational science, the Euler method (also called forward Euler method) is a first-order numerical procedure for solving ordinary differential equations (ODEs) with a given initial value. It is the most basic explicit method for numerical integration of ordinary differential equations. The method proceeds in a series of steps. At each step the y-value is calculated by evaluating the differential equation at the previous step, multiplying the result with the step-size and adding it to the last y-value: y_n+1 = y_n + stepSize * f(x_n, y_n).
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(description adapted from https://en.wikipedia.org/wiki/Euler_method )
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(see also: https://www.geeksforgeeks.org/euler-method-solving-differential-equation/ )
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*/
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/*
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Doctests
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> eulerStep(0, 0.1, 0, function(x, y){return x})
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0
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> eulerStep(2, 1, 1, function(x, y){return x * x})
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5
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> eulerFull(0, 3, 1, 0, function(x, y){return x})
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[{"x": 0, "y": 0}, {"x": 1, "y": 0}, {"x": 2, "y": 1}, {"x": 3, "y": 3}]
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> eulerFull(3, 4, 0.5, 1, function(x, y){return x * x})
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[{"x": 3, "y": 1}, {"x": 3.5, "y": 5.5}, {"x": 4, "y": 11.625}]
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*/
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function eulerStep (xCurrent, stepSize, yCurrent, differentialEquation) {
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/**
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* In mathematics and computational science, the Euler method (also called forward Euler method) is a first-order
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* numerical procedure for solving ordinary differential equations (ODEs) with a given initial value. It is the most
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* basic explicit method for numerical integration of ordinary differential equations. The method proceeds in a series
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* of steps. At each step the y-value is calculated by evaluating the differential equation at the previous step,
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* multiplying the result with the step-size and adding it to the last y-value: y_n+1 = y_n + stepSize * f(x_n, y_n).
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*
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* (description adapted from https://en.wikipedia.org/wiki/Euler_method)
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* @see https://www.geeksforgeeks.org/euler-method-solving-differential-equation/
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*/
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export function eulerStep (xCurrent, stepSize, yCurrent, differentialEquation) {
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// calculates the next y-value based on the current value of x, y and the stepSize
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const yNext = yCurrent + stepSize * differentialEquation(xCurrent, yCurrent)
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return yNext
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return yCurrent + stepSize * differentialEquation(xCurrent, yCurrent)
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}
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function eulerFull (xStart, xEnd, stepSize, yStart, differentialEquation) {
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export function eulerFull (xStart, xEnd, stepSize, yStart, differentialEquation) {
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// loops through all the steps until xEnd is reached, adds a point for each step and then returns all the points
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const points = [{ x: xStart, y: yStart }]
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let yCurrent = yStart
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@ -37,72 +28,3 @@ function eulerFull (xStart, xEnd, stepSize, yStart, differentialEquation) {
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return points
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}
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function plotLine (label, points, width, height) {
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// utility function to plot the results
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// container needed to control the size of the canvas
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const container = document.createElement('div')
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container.style.width = width + 'px'
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container.style.height = height + 'px'
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document.body.append(container)
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// the canvas for plotting
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const canvas = document.createElement('canvas')
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container.append(canvas)
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// Chart-class from chartjs
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const chart = new Chart(canvas, { // eslint-disable-line
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type: 'scatter',
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data: {
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datasets: [{
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label: label,
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data: points,
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showLine: true,
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fill: false,
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tension: 0,
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borderColor: 'black'
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}]
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},
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options: {
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maintainAspectRatio: false,
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responsive: true
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}
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})
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}
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function exampleEquation1 (x, y) {
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return x
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}
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// example from https://en.wikipedia.org/wiki/Euler_method
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function exampleEquation2 (x, y) {
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return y
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}
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// example from https://www.geeksforgeeks.org/euler-method-solving-differential-equation/
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function exampleEquation3 (x, y) {
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return x + y + x * y
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}
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const points1 = eulerFull(0, 4, 0.1, 0, exampleEquation1)
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const points2 = eulerFull(0, 4, 0.1, 1, exampleEquation2)
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const points3 = eulerFull(0, 0.1, 0.025, 1, exampleEquation3)
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console.log(points1)
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console.log(points2)
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console.log(points3)
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// plot the results if the script is executed in a browser with a window-object
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if (typeof window !== 'undefined') {
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const script = document.createElement('script')
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// using chartjs
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script.src = 'https://www.chartjs.org/dist/2.9.4/Chart.min.js'
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script.onload = function () {
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plotLine('example 1: dy/dx = x', points1, 600, 400)
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plotLine('example 2: dy/dx = y', points2, 600, 400)
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plotLine('example 3: dy/dx = x + y + x * y', points3, 600, 400)
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}
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document.body.append(script)
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}
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