Created
March 3, 2011 04:22
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Xorshift random on JavaScript #js
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// @license = public domain | |
// =Usage | |
// Number = Xorshift.random(); | |
// | |
// var xor128 = Xorshift.init(); | |
// Array = xor128.make(1000000); | |
(function() { | |
//var floor = Math.floor, | |
// random = Math.random; | |
// Xorshift Class | |
function Xor128(x, // @param Number: | |
y, // @param Number: | |
z, // @param Number: | |
w) { // @param Number: | |
this.x = (x ? x >>> 0 : 123456789); | |
this.y = (y ? y >>> 0 : 362436069); | |
this.z = (z ? z >>> 0 : 521288629); | |
this.w = (w ? w >>> 0 : 88675123); | |
} | |
function Xor128_init() { | |
//return new Xor128(floor(random() * 1000000000000)); | |
return new Xor128(Date.now()); | |
} | |
Xor128.init = Xor128_init; | |
function next() { // @return Number: | |
var me = this, x = me.x, w = me.w, | |
t = x ^ (x << 11); | |
me.x = me.y = me.z = w; | |
return me.w = (w ^ (w >> 19)) ^ (t ^ (t >> 8)); | |
} | |
Xor128.prototype.next = next; | |
function make(cnt) { // @param Number: | |
// @return Array[Number]: | |
var i = 0, result = []; | |
for (; i < cnt; ++i) { | |
result[i] = this.next(); | |
} | |
return result; | |
} | |
Xor128.prototype.make = make; | |
function Xor128_random() { | |
return Xor128_init().make(3)[2] / 4294967296 * 2; | |
} | |
Xor128.random = Xor128_random; | |
Xorshift = Xor128; | |
})(); |
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Reading on this implementation line 37 should probably read:
Also
>>
should probably be>>>
.