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# incrnansumabs

> Compute a sum of absolute values incrementally, ignoring `NaN` values.

<section class="intro">

The sum of absolute values is defined as

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

<div class="equation" align="center" data-raw-text="s = \sum_{i=0}^{n-1} |x_i|" data-equation="eq:sum_absolute_values">
    <img src="https://cdn.rawgit.com/stdlib-js/stdlib/98f065ffc1f7e76a1df57a5817ac0aa258b7c40b/lib/node_modules/@stdlib/stats/incr/nansumabs/docs/img/equation_sum_absolute_values.svg" alt="Equation for the sum of absolute values.">
    <br>
</div>

<!-- </equation> -->

</section>

<!-- /.intro -->

<section class="usage">

## Usage

```javascript
var incrnansumabs = require( '@stdlib/stats/incr/nansumabs' );
```

#### incrnansumabs()

Returns an accumulator `function` which incrementally computes a sum of absolute values, ignoring `NaN` values.

```javascript
var accumulator = incrnansumabs();
```

#### accumulator( \[x] )

If provided an input value `x`, the accumulator function returns an updated sum. If not provided an input value `x`, the accumulator function returns the current sum.

```javascript
var accumulator = incrnansumabs();

var sum = accumulator( 2.0 );
// returns 2.0

sum = accumulator( -1.0 );
// returns 3.0

sum = accumulator( NaN );
// returns 3.0

sum = accumulator( -3.0 );
// returns 6.0

sum = accumulator();
// returns 6.0
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   Input values are **not** type checked. If non-numeric inputs are possible, you are advised to type check and handle accordingly **before** passing the value to the accumulator function.
-   For long running accumulations or accumulations of large numbers, care should be taken to prevent overflow.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var randu = require( '@stdlib/random/base/randu' );
var incrnansumabs = require( '@stdlib/stats/incr/nansumabs' );

var accumulator;
var v;
var i;

// Initialize an accumulator:
accumulator = incrnansumabs();

// For each simulated datum, update the sum...
for ( i = 0; i < 100; i++ ) {
    if ( randu() < 0.2 ) {
        v = NaN;
    } else {
        v = ( randu()*100.0 ) - 50.0;
    }
    accumulator( v );
}
console.log( accumulator() );
```

</section>

<!-- /.examples -->

<section class="links">

</section>

<!-- /.links -->
