# erfinv
> [Inverse error function][inverse-error-function].
The [inverse error function][inverse-error-function] is defined in terms of the [Maclaurin series][maclaurin-series]
where `c_0 = 1` and
## Usage
```javascript
var erfinv = require( '@stdlib/math/base/special/erfinv' );
```
#### erfinv( x )
Evaluates the [inverse error function][inverse-error-function].
```javascript
var y = erfinv( 0.5 );
// returns ~0.4769
y = erfinv( 0.8 );
// returns ~0.9062
y = erfinv( -1.0 );
// returns -Infinity
y = erfinv( 1.0 );
// returns Infinity
```
The domain of `x` is restricted to `[-1,1]`. If `|x| > 1`, the function returns `NaN`.
```javascript
var y = erfinv( -3.14 );
// returns NaN
```
If provided `NaN`, the function returns `NaN`.
```javascript
var y = erfinv( NaN );
// returns NaN
```
The [inverse error function][inverse-error-function] is an [odd function][odd-function]; i.e., `erfinv(-x) = -erfinv(x)`. Thus, in accordance with the [IEEE 754][ieee754] standard, if provided `-0`, the function returns `-0`.
```javascript
var y = erfinv( -0.0 );
// returns -0.0
```
## Examples
```javascript
var linspace = require( '@stdlib/array/linspace' );
var erfinv = require( '@stdlib/math/base/special/erfinv' );
var x = linspace( -1.0, 1.0, 100 );
var y;
var i;
for ( i = 0; i < x.length; i++ ) {
y = erfinv( x[ i ] );
console.log( 'x: %d, erfinv(x): %d', x[ i ], y );
}
```
[inverse-error-function]: https://en.wikipedia.org/wiki/Error_function#Inverse_functions
[maclaurin-series]: http://mathworld.wolfram.com/MaclaurinSeries.html
[odd-function]: https://en.wikipedia.org/wiki/Even_and_odd_functions
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
