| 1 | void function(root){
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| 2 | "use strict"
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| 3 |
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| 4 | var numbers = {}
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| 5 | , u = require('totemizer')
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| 6 | , boo = require('boo')
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| 7 | , rational
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| 8 | , apply = u.liberate(Function.prototype.apply)
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| 9 | ;
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| 10 |
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| 11 |
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| 12 | function checkInput(input){ return (input && input.init === rational.init) ? input : rat(input) }
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| 13 |
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| 14 | function gcd(a, b){
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| 15 | var t;
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| 16 | a = Math.abs(a)
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| 17 | b = Math.abs(b)
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| 18 | while (b > 0) {
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| 19 | t = b
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| 20 | b = a % b
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| 21 | a = t
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| 22 | }
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| 23 | return a
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| 24 | }
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| 25 |
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| 26 | function lcm(a, b){ return Math.abs(a*b)/gcd(a,b) }
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| 27 |
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| 28 | function hashify(r){ return r[0]+'/'+r[1] }
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| 29 |
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| 30 | function display(r){ return ''+r[0]+(r[1]!=1?'/'+r[1]:'') }
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| 31 |
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| 32 | function val(r){ return r[0]/r[1] }
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| 33 |
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| 34 | function add(x, y){ return rat(x[0]*y[1]+y[0]*x[1], x[1]*y[1]) }
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| 35 |
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| 36 | function subtract(x, y){ return rat(x[0]*y[1]-y[0]*x[1], x[1]*y[1]) }
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| 37 |
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| 38 | function multiply(x, y){ return rat(x[0]*y[0], x[1]*y[1]) }
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| 39 |
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| 40 | function divide(x, y){ return rat(x[0]*y[1], y[0]*x[1]) }
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| 41 |
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| 42 | rational = boo.Base.derive({
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| 43 | init : function(numerator, denominator){
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| 44 | this[0] = numerator
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| 45 | this[1] = denominator
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| 46 | }
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| 47 | , toString : u.enslave(hashify)
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| 48 | , display : u.enslave(display)
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| 49 |
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| 50 | , val : u.enslave(val)
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| 51 |
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| 52 | , add : u.enslave(add)
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| 53 | , plus : u.enslave(add)
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| 54 |
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| 55 | , subtract : u.enslave(subtract)
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| 56 | , minus : u.enslave(subtract)
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| 57 | , sub: u.enslave(subtract)
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| 58 |
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| 59 | , multiply : u.enslave(multiply)
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| 60 | , times : u.enslave(multiply)
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| 61 | , mul: u.enslave(multiply)
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| 62 |
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| 63 | , divide : u.enslave(divide)
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| 64 | , per : u.enslave(divide)
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| 65 | , div: u.enslave(divide)
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| 66 |
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| 67 | })
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| 68 |
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| 69 | function rat(numerator, denominator){
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| 70 |
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| 71 | var index, divisor;
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| 72 |
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| 73 | if ( ! u.isInt(numerator) ) {
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| 74 | throw new Error('invalid argument '+numerator+' ('+(typeof numerator)+')')
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| 75 | } else if ( typeof numerator === 'string' ) {
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| 76 | numerator = Number(numerator)
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| 77 | }
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| 78 |
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| 79 | if ( ! u.isInt(denominator) ) {
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| 80 | denominator = 1
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| 81 | } else if ( typeof denominator === 'string' ) {
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| 82 | denominator = Number(denominator)
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| 83 | }
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| 84 |
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| 85 | if ( denominator === 0 ) {
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| 86 |
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| 87 | if ( numerator !== 0 ) numerator = 1
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| 88 |
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| 89 | } else {
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| 90 |
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| 91 | divisor = gcd(numerator, denominator)
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| 92 | if ( Math.abs(divisor) > 1 ) {
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| 93 | numerator = numerator / divisor
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| 94 | denominator = denominator / divisor
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| 95 | }
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| 96 |
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| 97 | if ( denominator < 0 ) {
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| 98 | numerator *= -1
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| 99 | denominator *= -1
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| 100 | }
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| 101 | }
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| 102 |
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| 103 | index = hashify([numerator, denominator])
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| 104 |
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| 105 | if ( numbers[index] === undefined ) {
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| 106 | numbers[index] = rational.make(numerator, denominator)
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| 107 | }
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| 108 |
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| 109 | return numbers[index]
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| 110 |
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| 111 | }
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| 112 |
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| 113 | rat.checkInput = checkInput
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| 114 | rat.gcd = function(a, b){ return rat(gcd(a[0],b[0]), lcm(a[1],b[1])) }
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| 115 | rat.lcm = function(a, b){ return rat(lcm(a[0],b[0]), gcd(a[1],b[1])) }
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| 116 | rat.add = add
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| 117 | rat.div = divide
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| 118 | rat.sub = subtract
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| 119 | rat.mul = multiply
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| 120 |
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| 121 | if ( typeof module !== 'undefined' && module.exports ) {
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| 122 | module.exports = rat
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| 123 | } else {
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| 124 | root.factory = rat
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| 125 | }
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| 126 |
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| 127 | }(this)
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