# erf
> [Error function][error-function].
The [error function][error-function] is defined as
## Usage
```javascript
var erf = require( '@stdlib/math/base/special/erf' );
```
#### erf( x )
Evaluates the [error function][error-function].
```javascript
var y = erf( 2.0 );
// returns ~0.9953
y = erf( -1.0 );
// returns ~-0.8427
```
If provided `NaN`, the function returns `NaN`.
```javascript
var y = erf( NaN );
// returns NaN
```
The [error function][error-function] is an [odd function][odd-function]; i.e., `erf(-x) = -erf(x)`. Thus, in accordance with the [IEEE 754][ieee754] standard, if provided `-0`, the function returns `-0`.
```javascript
var y = erf( -0.0 );
// returns -0.0
```
## Examples
```javascript
var linspace = require( '@stdlib/array/linspace' );
var erf = require( '@stdlib/math/base/special/erf' );
var x = linspace( -10.0, 10.0, 100 );
var y;
var i;
for ( i = 0; i < x.length; i++ ) {
y = erf( x[ i ] );
console.log( 'x: %d, erf(x): %d', x[ i ], y );
}
```
[error-function]: https://en.wikipedia.org/wiki/Error_function
[odd-function]: https://en.wikipedia.org/wiki/Even_and_odd_functions
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
