1 | /**
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2 | * Math.js can easily be extended with functions and variables using the
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3 | * `import` function. The function `import` accepts a module name or an object
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4 | * containing functions and variables.
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5 | */
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6 |
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7 | // load math.js (using node.js)
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8 | const math = require('../index')
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9 |
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10 | /**
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11 | * Define new functions and variables
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12 | */
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13 | math.import({
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14 | myConstant: 42,
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15 | hello: function (name) {
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16 | return 'hello, ' + name + '!'
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17 | }
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18 | })
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19 |
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20 | // defined methods can be used in both JavaScript as well as the parser
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21 | print(math.myConstant * 2) // 84
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22 | print(math.hello('user')) // 'hello, user!'
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23 |
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24 | print(math.eval('myConstant + 10')) // 52
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25 | print(math.eval('hello("user")')) // 'hello, user!'
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26 |
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27 | /**
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28 | * Import the math library numbers.js, https://github.com/sjkaliski/numbers.js
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29 | * The library must be installed first using npm:
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30 | * npm install numbers
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31 | */
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32 | try {
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33 | // load the numbers.js library
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34 | const numbers = require('numbers')
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35 |
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36 | // import the numbers.js library into math.js
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37 | math.import(numbers, { wrap: true, silent: true })
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38 |
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39 | if (math.fibonacci) {
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40 | // calculate fibonacci
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41 | print(math.fibonacci(7)) // 13
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42 | print(math.eval('fibonacci(7)')) // 13
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43 | }
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44 | } catch (err) {
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45 | console.log('Warning: To use numbers.js, the library must ' +
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46 | 'be installed first via `npm install numbers`.')
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47 | }
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48 |
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49 | /**
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50 | * Import the math library numeric.js, https://github.com/sloisel/numeric
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51 | * The library must be installed first using npm:
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52 | * npm install numeric
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53 | */
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54 | try {
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55 | // load the numeric.js library
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56 | const numeric = require('numeric')
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57 |
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58 | // import the numeric.js library into math.js
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59 | math.import(numeric, { wrap: true, silent: true })
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60 |
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61 | if (math.eig) {
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62 | // calculate eigenvalues of a matrix
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63 | print(math.eval('eig([1, 2; 4, 3])').lambda.x) // [5, -1]
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64 |
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65 | // solve AX = b
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66 | const A = math.eval('[1, 2, 3; 2, -1, 1; 3, 0, -1]')
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67 | const b = [9, 8, 3]
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68 | print(math.solve(A, b)) // [2, -1, 3]
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69 | }
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70 | } catch (err) {
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71 | console.log('Warning: To use numeric.js, the library must ' +
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72 | 'be installed first via `npm install numeric`.')
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73 | }
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74 |
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75 | /**
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76 | * By default, the function import does not allow overriding existing functions.
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77 | * Existing functions can be overridden by specifying option `override: true`
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78 | */
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79 | math.import({
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80 | pi: 3.14
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81 | }, {
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82 | override: true
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83 | })
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84 |
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85 | print(math.pi) // returns 3.14 instead of 3.141592653589793
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86 |
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87 | /**
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88 | * Helper function to output a value in the console. Value will be formatted.
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89 | * @param {*} value
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90 | */
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91 | function print (value) {
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92 | const precision = 14
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93 | console.log(math.format(value, precision))
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94 | }
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