# gammaln
> [Natural logarithm][@stdlib/math/base/special/ln] of the [gamma][@stdlib/math/base/special/gamma] function.
## Usage
```javascript
var gammaln = require( '@stdlib/math/base/special/gammaln' );
```
#### gammaln( x )
Evaluates the [natural logarithm][@stdlib/math/base/special/ln] of the [gamma function][@stdlib/math/base/special/gamma].
```javascript
var v = gammaln( 2.0 );
// returns 0.0
v = gammaln( 1.0 );
// returns 0.0
v = gammaln( 4.0 );
// returns ~1.792
v = gammaln( -0.5 );
// returns ~1.266
v = gammaln( 0.5 );
// returns ~0.572
v = gammaln( 0.0 );
// returns Infinity
v = gammaln( NaN );
// returns NaN
```
## Examples
```javascript
var linspace = require( '@stdlib/array/linspace' );
var gammaln = require( '@stdlib/math/base/special/gammaln' );
var x = linspace( -10.0, 10.0, 100 );
var v;
var i;
for ( i = 0; i < x.length; i++ ) {
v = gammaln( x[ i ] );
console.log( 'x: %d, f(x): %d', x[ i ], v );
}
```
[@stdlib/math/base/special/gamma]: https://www.npmjs.com/package/@stdlib/math/tree/main/base/special/gamma
[@stdlib/math/base/special/ln]: https://www.npmjs.com/package/@stdlib/math/tree/main/base/special/ln