fast-random
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Fast simple seedable pseudo-random number generator
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Simple fast seedable pseudo-random number generator
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](https://en.wikipedia.org/wiki/Lehmer_random_number_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
```sh
npm install --save fast-random
```
## API Summary
Get a new random number generator
```js
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 (SEED_VALUE is an integer)
* `nextInt()`: get the next integer value _(1 <= x <= 2147483646)_
* `nextFloat()`: get the next float value _(0 <= x < 1)_
## Examples
### General use
```js
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());
}
```
```js
const random = require('fast-random');
const seed = Date.now();
const r = random(seed);
```
```js
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);
}
```
* https://en.wikipedia.org/wiki/Lehmer_random_number_generator
* http://www.firstpr.com.au/dsp/rand31/
* http://lab.polygonal.de/2007/04/21/a-good-pseudo-random-number-generator-prng/