npm package: @stdlib/math-iter-special-betaln
Description: Create an iterator which evaluates the natural logarithm of the beta function.
Author: The Stdlib Authors
Latest version: 0.2.3

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# iterBetaln

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> Create an [iterator][mdn-iterator-protocol] which iteratively evaluates the [natural logarithm of the beta function][@stdlib/math/base/special/betaln].

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

<!-- /.intro -->

<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/math-iter-special-betaln
```

</section>

<section class="usage">

## Usage

```javascript
var iterBetaln = require( '@stdlib/math-iter-special-betaln' );
```

#### iterBetaln( x, y )

Returns an [iterator][mdn-iterator-protocol] which iteratively evaluates the [natural logarithm of the beta function][@stdlib/math/base/special/betaln].

```javascript
var array2iterator = require( '@stdlib/array-to-iterator' );

var x = array2iterator( [ 1.0, 5.0, 4.0 ] );
var y = array2iterator( [ 1.0, 0.2, 1.0 ] );

var it = iterBetaln( x, y );
// returns <Object>

var r = it.next().value;
// returns 0.0

r = it.next().value;
// returns ~1.218

r = it.next().value;
// returns ~-1.386

// ...
```

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

-   **next**: function which returns an [iterator][mdn-iterator-protocol] 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][mdn-iterator-protocol] and returns a single (optional) argument in an [iterator][mdn-iterator-protocol] protocol-compliant object.

If provided a numeric value as an [`iterator`][mdn-iterator-protocol] argument, the value is broadcast as an **infinite** [iterator][mdn-iterator-protocol] which **always** returns the provided value.

```javascript
var array2iterator = require( '@stdlib/array-to-iterator' );

var x = array2iterator( [ 1.0, 5.0 ] );

var it = iterBetaln( x, 2.0 );
// returns <Object>

var v = it.next().value;
// returns ~-0.6931

v = it.next().value;
// returns ~-3.4012

var bool = it.next().done;
// returns true
```

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

## Notes

-   If an iterated value is non-numeric (including `NaN`), the returned [iterator][mdn-iterator-protocol] returns `NaN`. If non-numeric iterated values are possible, you are advised to provide an [`iterator`][mdn-iterator-protocol] which type checks and handles non-numeric values accordingly.
-   The length of the returned [iterator][mdn-iterator-protocol] is equal to the length of the shortest provided [iterator][mdn-iterator-protocol]. In other words, the returned [iterator][mdn-iterator-protocol] ends once **one** of the provided [iterators][mdn-iterator-protocol] ends.
-   If an environment supports `Symbol.iterator` **and** a provided [iterator][mdn-iterator-protocol] is iterable, the returned [iterator][mdn-iterator-protocol] is iterable.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var uniform = require( '@stdlib/random-iter-uniform' );
var iterBetaln = require( '@stdlib/math-iter-special-betaln' );

// Create seeded iterators for generating pseudorandom numbers:
var x = uniform( 0.0, 2.0, {
    'seed': 1234,
    'iter': 10
});

var y = uniform( 0.0, 2.0, {
    'seed': 4567,
    'iter': 10
});

// Create an iterator which consumes the pseudorandom number iterators:
var it = iterBetaln( x, y );

// Perform manual iteration...
var r;
while ( true ) {
    r = it.next();
    if ( r.done ) {
        break;
    }
    console.log( r.value );
}
```

</section>

<!-- /.examples -->

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<section class="references">

</section>

<!-- /.references -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/math-base/special/betaln`][@stdlib/math/base/special/betaln]</span><span class="delimiter">: </span><span class="description">natural logarithm of the beta function.</span>
-   <span class="package-name">[`@stdlib/math-iter/special/beta`][@stdlib/math/iter/special/beta]</span><span class="delimiter">: </span><span class="description">create an iterator which evaluates the beta function.</span>

</section>

<!-- /.related -->

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<section class="main-repo" >

* * *

## 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

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---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

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[mdn-iterator-protocol]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#The_iterator_protocol

<!-- <related-links> -->

[@stdlib/math/base/special/betaln]: https://www.npmjs.com/package/@stdlib/math-base-special-betaln

[@stdlib/math/iter/special/beta]: https://www.npmjs.com/package/@stdlib/math-iter-special-beta

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