96 lines
2.5 KiB
JavaScript
96 lines
2.5 KiB
JavaScript
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/**
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* Math.js can easily be extended with functions and variables using the
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* `import` function. The function `import` accepts a module name or an object
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* containing functions and variables.
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*/
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// load math.js (using node.js)
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const { create, all } = require('..')
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const math = create(all)
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/**
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* Define new functions and variables
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*/
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math.import({
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myConstant: 42,
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hello: function (name) {
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return 'hello, ' + name + '!'
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}
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})
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// defined methods can be used in both JavaScript as well as the parser
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print(math.myConstant * 2) // 84
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print(math.hello('user')) // 'hello, user!'
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print(math.evaluate('myConstant + 10')) // 52
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print(math.evaluate('hello("user")')) // 'hello, user!'
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/**
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* Import the math library numbers.js, https://github.com/sjkaliski/numbers.js
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* The library must be installed first using npm:
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* npm install numbers
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*/
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try {
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// load the numbers.js library
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const numbers = require('numbers')
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// import the numbers.js library into math.js
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math.import(numbers, { wrap: true, silent: true })
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if (math.fibonacci) {
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// calculate fibonacci
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print(math.fibonacci(7)) // 13
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print(math.evaluate('fibonacci(7)')) // 13
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}
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} catch (err) {
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console.log('Warning: To use numbers.js, the library must ' +
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'be installed first via `npm install numbers`.')
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}
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/**
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* Import the math library numeric.js, https://github.com/sloisel/numeric
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* The library must be installed first using npm:
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* npm install numeric
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*/
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try {
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// load the numeric.js library
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const numeric = require('numeric')
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// import the numeric.js library into math.js
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math.import(numeric, { wrap: true, silent: true })
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if (math.eig) {
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// calculate eigenvalues of a matrix
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print(math.evaluate('eig([1, 2; 4, 3])').lambda.x) // [5, -1]
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// solve AX = b
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const A = math.evaluate('[1, 2, 3; 2, -1, 1; 3, 0, -1]')
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const b = [9, 8, 3]
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print(math.solve(A, b)) // [2, -1, 3]
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}
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} catch (err) {
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console.log('Warning: To use numeric.js, the library must ' +
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'be installed first via `npm install numeric`.')
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}
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/**
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* By default, the function import does not allow overriding existing functions.
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* Existing functions can be overridden by specifying option `override: true`
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*/
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math.import({
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pi: 3.14
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}, {
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override: true
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})
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print(math.pi) // returns 3.14 instead of 3.141592653589793
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/**
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* Helper function to output a value in the console. Value will be formatted.
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* @param {*} value
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*/
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function print (value) {
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const precision = 14
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console.log(math.format(value, precision))
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}
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