lcg-random: (Predictable) LCG Random Number Generator

Creates a Linear Congruential Generator
for generating random numbers. The random numbers are predictable/reproducable, which is useful for
(unit) testing purposes.

Installation

npm install lcg-random --save

Usage

A call to the exported function returns a function that generates a random number
on every call:

var lcgRandom = require("lcg-random");

// Outputs 0.000005748588591814041 0.6551540484651923 0.30481433868408203
var rand1 = lcgRandom();
console.log(rand1(), rand1(), rand1());

// Also outputs 0.000005748588591814041 0.6551540484651923 0.30481433868408203
var rand2 = lcgRandom();
console.log(rand2(), rand2(), rand2());

API

$3

Returns a function that returns a random number between 0 and 1 every time it is called.

The function used is

> X_n+1 = (multiplier \* X_n + increment) % modulus

Every component of the function can be customized by setting it in the options argument.
The default values are the ones from Park and Miller's MINSTD.

- options.seed - number (0 ≤ options.seed < options.modulus)
Seed (start value) for the generator.
Default: 1

- options.modulus - modulus (0 < options.modulus)
Modulus for the generator.
Default: 2³¹-1

- options.multiplier - modulus (0 < options.multiplier < options.modulus)
Multiplier for the generator.
Default: 7⁵

- options.increment - modulus (0 ≤ options.increment < options.modulus)
Increment for the generator.
Default: 0

Project Status



![Browser Support
](https://ci.testling.com/remko/lcg-random)

Changelog

$3

- Allow increment of 0 (enabling Lehmer RNGs) (\#1)
- Use MINSTD as default values (\#1)
- Change default seed to 1 (to enable MINSTD)
- Add bounds checks

$3

- Fix index in package.json

$3

- Initial version