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https://github.com/stdlib-js/simulate-iter-triangle-wave

Create an iterator which generates a triangle wave.
https://github.com/stdlib-js/simulate-iter-triangle-wave

iter iterate iteration iterator javascript node node-js nodejs periodic processing signal simulate simulation stdlib triangle wave waveform

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Create an iterator which generates a triangle wave.

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README 

        



  

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# iterTriangleWave



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



> Create an iterator which generates a triangle wave.



A triangle waveform is represented by the following equation



```math

f(t; \tau, a, \varphi) = \frac{2a}{\pi} \mathop{\mathrm{arcsin}} \sin \frac{2\pi(t-\varphi)}{\tau}

```



where `τ` is the period, `a` is the peak amplitude, and `φ` is the phase offset.



## Installation



```bash

npm install @stdlib/simulate-iter-triangle-wave

```



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 iterTriangleWave = require( '@stdlib/simulate-iter-triangle-wave' );

```



#### iterTriangleWave( \[options] )



Returns an iterator which generates a triangle wave.



```javascript

var it = iterTriangleWave();

// returns 



var v = it.next().value;

// returns 



v = it.next().value;

// returns 



v = it.next().value;

// returns 



// ...

```



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.



The function supports the following `options`:



-   **period**: period (i.e., the number of iterations before a waveform repeats). Default: `10`.

-   **amplitude**: peak amplitude. Default: `1.0`.

-   **offset**: phase offset (in units of iterations; zero-based). A negative offset translates a waveform to the left. A positive offset translates a waveform to the right. Default: `0`.

-   **iter**: number of iterations. Default: `1e308`.



By default, the function returns an iterator which generates a triangle wave that repeats every `10` iterations. To specify an alternative period, set the `period` option.



```javascript

var opts = {

    'period': 4

};



var it = iterTriangleWave( opts );

// returns 



var v = it.next().value;

// returns 0.0



v = it.next().value;

// returns 1.0



v = it.next().value;

// returns 0.0



v = it.next().value;

// returns -1.0



v = it.next().value;

// returns 0.0



// ...

```



To adjust at what point the iterator begins in the waveform cycle, set the phase `offset` option. For example, to translate the waveform to the left,



```javascript

var opts = {

    'period': 4,

    'offset': -1

};



var it = iterTriangleWave( opts );

// returns 



var v = it.next().value;

// returns 1.0



v = it.next().value;

// returns 0.0



v = it.next().value;

// returns -1.0



v = it.next().value;

// returns 0.0



v = it.next().value;

// returns 1.0



// ...

```



To translate the waveform to the right,



```javascript

var opts = {

    'period': 4,

    'offset': 1

};



var it = iterTriangleWave( opts );

// returns 



var v = it.next().value;

// returns -1.0



v = it.next().value;

// returns 0.0



v = it.next().value;

// returns 1.0



v = it.next().value;

// returns 0.0



v = it.next().value;

// returns -1.0



// ...

```



By default, the function returns an infinite iterator (i.e., an iterator which never ends). To limit the number of iterations, set the `iter` option.



```javascript

var opts = {

    'iter': 2

};

var it = iterTriangleWave( opts );

// returns 



var v = it.next().value;

// returns 



v = it.next().value;

// returns 



var bool = it.next().done;

// returns true

```



## Notes



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



## Examples



```javascript

var iterTriangleWave = require( '@stdlib/simulate-iter-triangle-wave' );



// Create an iterator:

var opts = {

    'period': 10,

    'amplitude': 10.0,

    'offset': -5,

    'iter': 100

};

var it = iterTriangleWave( opts );



// Perform manual iteration...

var v;

while ( true ) {

    v = it.next();

    if ( v.done ) {

        break;

    }

    console.log( v.value );

}

```



* * *



## See Also



-   [`@stdlib/simulate-iter/pulse`][@stdlib/simulate/iter/pulse]: create an iterator which generates a pulse waveform.

-   [`@stdlib/simulate-iter/sawtooth-wave`][@stdlib/simulate/iter/sawtooth-wave]: create an iterator which generates a sawtooth wave.

-   [`@stdlib/simulate-iter/sine-wave`][@stdlib/simulate/iter/sine-wave]: create an iterator which generates a sine wave.

-   [`@stdlib/simulate-iter/square-wave`][@stdlib/simulate/iter/square-wave]: create an iterator which generates a square wave.



* * *



## 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 © 2016-2024. The Stdlib [Authors][stdlib-authors].



[npm-image]: http://img.shields.io/npm/v/@stdlib/simulate-iter-triangle-wave.svg

[npm-url]: https://npmjs.org/package/@stdlib/simulate-iter-triangle-wave



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

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



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

[coverage-url]: https://codecov.io/github/stdlib-js/simulate-iter-triangle-wave?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/simulate-iter-triangle-wave/tree/deno

[deno-readme]: https://github.com/stdlib-js/simulate-iter-triangle-wave/blob/deno/README.md

[umd-url]: https://github.com/stdlib-js/simulate-iter-triangle-wave/tree/umd

[umd-readme]: https://github.com/stdlib-js/simulate-iter-triangle-wave/blob/umd/README.md

[esm-url]: https://github.com/stdlib-js/simulate-iter-triangle-wave/tree/esm

[esm-readme]: https://github.com/stdlib-js/simulate-iter-triangle-wave/blob/esm/README.md

[branches-url]: https://github.com/stdlib-js/simulate-iter-triangle-wave/blob/main/branches.md



[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/simulate-iter-triangle-wave/main/LICENSE



[@stdlib/simulate/iter/pulse]: https://github.com/stdlib-js/simulate-iter-pulse



[@stdlib/simulate/iter/sawtooth-wave]: https://github.com/stdlib-js/simulate-iter-sawtooth-wave



[@stdlib/simulate/iter/sine-wave]: https://github.com/stdlib-js/simulate-iter-sine-wave



[@stdlib/simulate/iter/square-wave]: https://github.com/stdlib-js/simulate-iter-square-wave