sunsevennv / xorshift
Random number generator (RNG) by Andreas Madsen & Emil Bay
Installs: 2
Dependents: 0
Suggesters: 0
Security: 0
Stars: 2
Watchers: 1
Forks: 11
Language:JavaScript
This package is auto-updated.
Last update: 2024-10-09 16:15:57 UTC
README
Pseudorandom number generator using xorshift128+
Certified RNG using javascript (for gambling related games)
This module was written by Andreas Madsen & Emil Bay and modified by Brendan Nash in order to be certified under a UK, Malta and Curacao Gambling License.
The module is free to use in line with the original authors intentions.
Gambling License & RNG Certification
Should your organisation require an RNG certificate in order to obtain a gambling license, we can provide you with a certificate for this module.
You can place your order here: https://gtec.curacaowebhosting.com/cart.php?gid=9
- email: brendan [at] gamblingTec.com
- WhatsApp: +44 (0)7498 105896
- Skype/Telegram: brendanjnash
Installation
npm install xorshift
Example
var xorshift = require('xorshift'); for (var i = 0; i < 10; i++) { console.log(xorshift.random()); // number in range [0, 1) }
Documentation
This module exports a default pseudo random generator. This generators seed have
already been set (using Date.now()
). If this is not suitable a custom
generator can be initialized using the constructor function
xorshift.constructor
. In both cases random numbers can be generated using
the two methods .random
and .randomint
.
var xorshift = require('xorshift');
xorshift.random()
This method returns a random 64-bit double, with its value in the range [0, 1).
That means 0 is inclusive and 1 is exclusive. This is equivalent to
Math.random()
.
console.log(xorshift.random()); // number between 0 and 1
This method will serve most purposes, for instance to randomly select between 2, 3 and 4, this function can be used:
function uniformint(a, b) { return Math.floor(a + xorshift().random() * (b - a)); } console.log(uniformint(2, 4));
xorshift.randomint()
This method returns a random 64-bit integer. Since JavaScript doesn't support 64-bit integers, the number is represented as an array with two elements in big-endian order.
This method is useful if high precision is required, the xorshift.random()
method won't allow you to get this precision since a 64-bit IEEE754 double
only contains the 52 most significant bits.
var bview = require('binary-view'); console.log(bview( new Uint32Array(xorshift.randomint()) ));
xorshift.constructor
This method is used to construct a new random generator, with a specific seed. This is useful when testing software where random numbers are involved and getting consistent results is important.
var XorShift = require('xorshift').constructor; var rng1 = new XorShift([1, 0, 2, 0]); var rng2 = new XorShift([1, 0, 2, 0]); assert(rng1.random() === rng2.random());
A XorShift
instance have both methods random
and randomint
. In fact the
xorshift
module is an instance of the XorShift
constructor.
Reference
This module implements the xorshift128+ pseudo random number generator.
This is the fastest generator passing BigCrush without systematic errors, but due to the relatively short period it is acceptable only for applications with a very mild amount of parallelism; otherwise, use a xorshift1024* generator. – http://xorshift.di.unimi.it
This source also has a reference implementation for the xorshift128+ generator. A wrapper around this implementation has been created and is used for testing this module. To compile and run it:
gcc -O2 reference.c -o reference ./reference <numbers> <seed0> <seed1>
<numbers>
can be any number greater than zero, and it will be the number of random numbers written tostdout
. The default value is10
.<seed0>
and<seed1>
forms the 128bit seed that the algorithm uses. Default is[1, 2]
.
License
This software is licensed under "MIT"
Copyright (c) 2014 Andreas Madsen & Emil Bay
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.