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102 lines
2.5 KiB
JavaScript
102 lines
2.5 KiB
JavaScript
/**
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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
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var math = require('../index');
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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.eval('myConstant + 10')); // 52
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print(math.eval('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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var 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.eval('fibonacci(7)')); // 13
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}
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}
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catch (err) {
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console.log('Warning: To import 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, http://numericjs.com/
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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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var 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.eval('eig([1, 2; 4, 3])').lambda.x); // [5, -1];
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// solve AX = b
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var A = math.eval('[1, 2, 3; 2, -1, 1; 3, 0, -1]');
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var b = [9, 8, 3];
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print(math.solve(A, b)); // [2, -1, 3]
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}
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}
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catch (err) {
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console.log('Warning: To import 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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var precision = 14;
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console.log(math.format(value, precision));
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}
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