https://github.com/remko/lcg-random

(Predictable) LCG Random Number Generator
https://github.com/remko/lcg-random

Last synced: 4 months ago
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(Predictable) LCG Random Number Generator

• Host: GitHub
• URL: https://github.com/remko/lcg-random
• Owner: remko
• Created: 2014-11-07T18:32:02.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2016-06-10T11:51:59.000Z (about 10 years ago)
• Last Synced: 2025-02-07T19:07:43.537Z (over 1 year ago)
• Language: JavaScript
• Size: 8.79 KB
• Stars: 1
• Watchers: 4
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# [lcg-random: (Predictable) LCG Random Number Generator](https://el-tramo.be/lcg-random)

Creates a [Linear Congruential Generator](http://en.wikipedia.org/wiki/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 0.000007826369259425611 0.13153778814316625 0.7556053221950332

	var rand1 = lcgRandom();

	console.log(rand1(), rand1(), rand1());

	// Also outputs 0.000007826369259425611 0.13153778814316625 0.7556053221950332

	var rand2 = lcgRandom();

	console.log(rand2(), rand2(), rand2());

## API

### `lcgRandom(options)`

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

The function used is 

> Xn+1 = (multiplier \* Xn + 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](https://en.wikipedia.org/wiki/Lehmer_random_number_generator).

- **`options.seed`** - *number (0 &leq; `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 &leq; `options.increment` < `options.modulus`)*  

    Increment for the generator.  

    Default: 0

## Project Status

[![Build Status](https://travis-ci.org/remko/lcg-random.svg?branch=master)](https://travis-ci.org/remko/lcg-random)

[![Coverage Status](https://coveralls.io/repos/remko/lcg-random/badge.png?branch=master)](https://coveralls.io/r/remko/lcg-random?branch=master)

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

](https://ci.testling.com/remko/lcg-random)

## Changelog

### 2.0.0 (2016-06-10)

- Allow increment of 0 (enabling Lehmer RNGs) ([\#1](https://github.com/remko/lcg-random/issues/1))

- Use [MINSTD](https://en.wikipedia.org/wiki/Lehmer_random_number_generator) as default values ([\#1](https://github.com/remko/lcg-random/issues/1))

- Change default `seed` to 1 (to enable MINSTD)

- Add bounds checks

### 1.0.2 (2014-11-09)

- Fix `index` in `package.json`

### 1.0.1 (2014-11-07)

- Initial version