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# itersumabs2

> Compute the sum of squared absolute values for all [iterated][mdn-iterator-protocol] values.

<section class="intro">

The sum of squared absolute values is defined as

<!-- <equation class="equation" label="eq:sum_squared_absolute_values" align="center" raw="s = \sum_{i=0}^{n-1} x_i^2" alt="Equation for the sum of squared absolute values."> -->

<div class="equation" align="center" data-raw-text="s = \sum_{i=0}^{n-1} x_i^2" data-equation="eq:sum_squared_absolute_values">
    <img src="https://cdn.rawgit.com/stdlib-js/stdlib/8105c9026f79efd4edf93c9377c3319699a8d61d/lib/node_modules/@stdlib/stats/iterators/sumabs2/docs/img/equation_sum_squared_absolute_values.svg" alt="Equation for the sum of squared absolute values.">
    <br>
</div>

<!-- </equation> -->

</section>

<!-- /.intro -->

<!-- Package usage documentation. -->

<section class="usage">

## Usage

```javascript
var itersumabs2 = require( '@stdlib/stats/iter/sumabs2' );
```

#### itersumabs2( iterator )

Computes the sum of squared absolute values for all [iterated][mdn-iterator-protocol] values.

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

var arr = array2iterator( [ -1.0, 2.0, -3.0, 4.0 ] );

var s = itersumabs2( arr );
// returns 30.0
```

</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.
-   For iterators which can generate many values or which may output large numbers, care should be taken to prevent overflow.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var runif = require( '@stdlib/random/iter/uniform' );
var itersumabs2 = require( '@stdlib/stats/iter/sumabs2' );

// Create an iterator for generating uniformly distributed pseudorandom numbers:
var rand = runif( -10.0, 10.0, {
    'seed': 1234,
    'iter': 100
});

// Compute the sum of squared absolute values:
var s = itersumabs2( rand );
// returns <number>

console.log( 'sumabs2: %d.', s );
```

</section>

<!-- /.examples -->

<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="references">

</section>

<!-- /.references -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="links">

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

</section>

<!-- /.links -->
