https://github.com/stdlib-js/random-iter-mt19937

Create an iterator for a 32-bit Mersenne Twister pseudorandom number generator.
https://github.com/stdlib-js/random-iter-mt19937

discrete generator integer javascript math mathematics node node-js nodejs prng pseudorandom rand randint random randu rng statistics stats stdlib uniform

Last synced: 2 months ago
JSON representation

Create an iterator for a 32-bit Mersenne Twister pseudorandom number generator.

• Host: GitHub
• URL: https://github.com/stdlib-js/random-iter-mt19937
• Owner: stdlib-js
• License: apache-2.0
• Created: 2021-06-15T18:12:45.000Z (over 4 years ago)
• Default Branch: main
• Last Pushed: 2025-05-19T03:25:40.000Z (5 months ago)
• Last Synced: 2025-06-20T03:18:15.515Z (4 months ago)
• Topics: discrete, generator, integer, javascript, math, mathematics, node, node-js, nodejs, prng, pseudorandom, rand, randint, random, randu, rng, statistics, stats, stdlib, uniform
• Language: JavaScript
• Homepage: https://github.com/stdlib-js/stdlib
• Size: 1.99 MB
• Stars: 2
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • Contributing: CONTRIBUTING.md
  • License: LICENSE
  • Code of conduct: CODE_OF_CONDUCT.md
  • Citation: CITATION.cff
  • Security: SECURITY.md

Awesome Lists containing this project

README

          


  

    About stdlib...

  

  
We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

  
The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

  
When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

  
To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!


# MT19937

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] 

> Create an iterator for a 32-bit [Mersenne Twister][mersenne-twister] pseudorandom number generator.

## Installation

```bash

npm install @stdlib/random-iter-mt19937

```

Alternatively,

-   To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).

-   If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).

-   For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).

The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

## Usage

```javascript

var iterator = require( '@stdlib/random-iter-mt19937' );

```

#### iterator( \[options] )

Returns an iterator for generating pseudorandom numbers via a 32-bit [Mersenne Twister][mersenne-twister] pseudorandom number generator.

```javascript

var it = iterator();

// returns 

var r = it.next().value;

// returns 

r = it.next().value;

// returns 

r = it.next().value;

// returns 

// ...

```

The function accepts the following `options`:

-   **normalized**: `boolean` indicating whether to return pseudorandom numbers on the interval `[0,1)`.

-   **seed**: pseudorandom number generator seed.

-   **state**: a [`Uint32Array`][@stdlib/array/uint32] containing pseudorandom number generator state. If provided, the function ignores the `seed` option.

-   **copy**: `boolean` indicating whether to copy a provided pseudorandom number generator state. Setting this option to `false` allows sharing state between two or more pseudorandom number generators. Setting this option to `true` ensures that a returned iterator has exclusive control over its internal pseudorandom number generator state. Default: `true`.

-   **iter**: number of iterations.

To return pseudorandom numbers on the interval `[0,1)`, set the `normalized` option.

```javascript

var it = iterator({

    'normalized': true

});

var r = it.next().value;

// returns 

```

To return an iterator having a specific initial state, set the iterator `state` option.

```javascript

var bool;

var it1;

var it2;

var r;

var i;

it1 = iterator();

// Generate pseudorandom numbers, thus progressing the generator state:

for ( i = 0; i < 1000; i++ ) {

    r = it1.next().value;

}

// Create a new iterator initialized to the current state of `it1`:

it2 = iterator({

    'state': it1.state

});

// Test that the generated pseudorandom numbers are the same:

bool = ( it1.next().value === it2.next().value );

// returns true

```

To seed the iterator, set the `seed` option.

```javascript

var it = iterator({

    'seed': 12345

});

var r = it.next().value;

// returns 3992670690

it = iterator({

    'seed': 12345

});

r = it.next().value;

// returns 3992670690

```

To limit the number of iterations, set the `iter` option.

```javascript

var it = iterator({

    'iter': 2

});

var r = it.next().value;

// returns 

r = it.next().value;

// returns 

r = it.next().done;

// returns true

```

The returned iterator protocol-compliant object has the following properties:

-   **next**: function which returns an iterator protocol-compliant object containing the next iterated value (if one exists) assigned to a `value` property and a `done` property having a `boolean` value indicating whether the iterator is finished.

-   **return**: function which closes an iterator and returns a single (optional) argument in an iterator protocol-compliant object.

-   **seed**: pseudorandom number generator seed.

-   **seedLength**: length of generator seed.

-   **state**: writable property for getting and setting the generator state.

-   **stateLength**: length of generator state.

-   **byteLength**: size (in bytes) of generator state.

## Notes

-   If an environment supports `Symbol.iterator`, the returned iterator is iterable.

-   [Mersenne Twister][mersenne-twister] is **not** a cryptographically secure PRNG, as the PRNG is based on a linear recursion. Any pseudorandom number sequence generated by a linear recursion is **insecure**, due to the fact that one can predict future generated outputs by observing a sufficiently long subsequence of generated values.

-   The PRNG has a period of `2^19937 - 1`.

-   If PRNG state is "shared" (meaning a state array was provided during iterator creation and **not** copied) and one sets the underlying generator state to a state array having a different length, the iterator does **not** update the existing shared state and, instead, points to the newly provided state array. In order to synchronize the output of the underlying generator according to the new shared state array, the state array for **each** relevant iterator and/or PRNG must be **explicitly** set.

-   If PRNG state is "shared" and one sets the underlying generator state to a state array of the same length, the PRNG state is updated (along with the state of all other iterator and/or PRNGs sharing the PRNG's state array).

## Examples

```javascript

var iterator = require( '@stdlib/random-iter-mt19937' );

var it;

var r;

// Create a seeded iterator for generating pseudorandom numbers:

it = iterator({

    'seed': 1234,

    'iter': 10

});

// Perform manual iteration...

while ( true ) {

    r = it.next();

    if ( r.done ) {

        break;

    }

    console.log( r.value );

}

```

* * *

## References

-   Matsumoto, Makoto, and Takuji Nishimura. 1998. "Mersenne Twister: A 623-dimensionally Equidistributed Uniform Pseudo-random Number Generator." _ACM Transactions on Modeling and Computer Simulation_ 8 (1). New York, NY, USA: ACM: 3–30. doi:[10.1145/272991.272995][@matsumoto:1998a].

-   Harase, Shin. 2017. "Conversion of Mersenne Twister to double-precision floating-point numbers." _ArXiv_ abs/1708.06018 (September). .

* * *

## See Also

-   [`@stdlib/random-base/mt19937`][@stdlib/random/base/mt19937]: A 32-bit Mersenne Twister pseudorandom number generator.

-   [`@stdlib/random-iter/minstd`][@stdlib/random/iter/minstd]: create an iterator for a linear congruential pseudorandom number generator (LCG) based on Park and Miller.

-   [`@stdlib/random-iter/minstd-shuffle`][@stdlib/random/iter/minstd-shuffle]: create an iterator for a linear congruential pseudorandom number generator (LCG) whose output is shuffled.

-   [`@stdlib/random-iter/randi`][@stdlib/random/iter/randi]: create an iterator for generating pseudorandom numbers having integer values.

-   [`@stdlib/random-iter/randu`][@stdlib/random/iter/randu]: create an iterator for generating uniformly distributed pseudorandom numbers between 0 and 1.

* * *

## Notice

This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].

## Copyright

Copyright © 2016-2025. The Stdlib [Authors][stdlib-authors].

[npm-image]: http://img.shields.io/npm/v/@stdlib/random-iter-mt19937.svg

[npm-url]: https://npmjs.org/package/@stdlib/random-iter-mt19937

[test-image]: https://github.com/stdlib-js/random-iter-mt19937/actions/workflows/test.yml/badge.svg?branch=main

[test-url]: https://github.com/stdlib-js/random-iter-mt19937/actions/workflows/test.yml?query=branch:main

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/random-iter-mt19937/main.svg

[coverage-url]: https://codecov.io/github/stdlib-js/random-iter-mt19937?branch=main

[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg

[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im

[stdlib]: https://github.com/stdlib-js/stdlib

[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors

[umd]: https://github.com/umdjs/umd

[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

[deno-url]: https://github.com/stdlib-js/random-iter-mt19937/tree/deno

[deno-readme]: https://github.com/stdlib-js/random-iter-mt19937/blob/deno/README.md

[umd-url]: https://github.com/stdlib-js/random-iter-mt19937/tree/umd

[umd-readme]: https://github.com/stdlib-js/random-iter-mt19937/blob/umd/README.md

[esm-url]: https://github.com/stdlib-js/random-iter-mt19937/tree/esm

[esm-readme]: https://github.com/stdlib-js/random-iter-mt19937/blob/esm/README.md

[branches-url]: https://github.com/stdlib-js/random-iter-mt19937/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/random-iter-mt19937/main/LICENSE

[mersenne-twister]: https://en.wikipedia.org/wiki/Mersenne_Twister

[@matsumoto:1998a]: https://doi.org/10.1145/272991.272995

[@stdlib/array/uint32]: https://github.com/stdlib-js/array-uint32

[@stdlib/random/base/mt19937]: https://github.com/stdlib-js/random-base-mt19937

[@stdlib/random/iter/minstd]: https://github.com/stdlib-js/random-iter-minstd

[@stdlib/random/iter/minstd-shuffle]: https://github.com/stdlib-js/random-iter-minstd-shuffle

[@stdlib/random/iter/randi]: https://github.com/stdlib-js/random-iter-randi

[@stdlib/random/iter/randu]: https://github.com/stdlib-js/random-iter-randu