# fast-random

Fast simple seedable pseudo-random number generator

## Stats

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fast-random
1002.0.46 years ago6 years ago

fast-random

Simple fast seedable pseudo-random number generator

## Purpose

Returns a single factory function that creates a new pseudo-random number generator (PRNG) based on the provided seed value. The generator returns 32-bit pseudo-random integers using the Lehmer/Park-Miller generator. This is a circular generator, which will cycle through all 2147483646 possible values before repeating
While not the most robust of PRNGs, the code has a very small footprint, is extremely quick and produces results good enough for many purposes. It has been written to work both within Node.js and in the browser

## Installation

``npm install --save fast-random``

## API Summary

Get a new random number generator
``````const random = require('fast-random');

const seed = 12345;
const generator = random(seed);``````

The returned generator contains the following functions
• `seed(SEED_VALUE)`: set the current seed value (SEEDVALUE is an integer)
• `nextInt()`: get the next integer value (1 <= x <= 2147483646)
• `nextFloat()`: get the next float value (0 <= x < 1)

## Examples

### General use

``````const random = require('fast-random');

// create a new generator
const seed = 12345;
const r = random(seed);

// produce some integer values
for (let i = 0; i < 8; ++i) {
console.log(r.nextInt());
}

// reset the seed
r.seed(seed);

// produce some floating point values
for (let j = 0; j < 8; ++j) {
console.log(r.nextFloat());
}``````

### Set seed from current time

``````const random = require('fast-random');

const seed = Date.now();
const r = random(seed);``````

### Get integers in a given range

``````const random = require('fast-random');

const seed = 12345;
const r = random(seed);

// get random number between a and b inclusive, ie (a <= x <= b)
function getRandomBetween(a, b) {
return a + r.nextInt() % (b - a + 1);
}``````