# Natural Logarithm
> Evaluate the [natural logarithm][natural-logarithm].
## Usage
```javascript
var ln = require( '@stdlib/math/base/special/ln' );
```
#### ln( x )
Evaluates the [natural logarithm][natural-logarithm].
```javascript
var v = ln( 4.0 );
// returns ~1.386
v = ln( 0.0 );
// returns -Infinity
v = ln( Infinity );
// returns Infinity
v = ln( NaN );
// returns NaN
```
For negative numbers, the [natural logarithm][natural-logarithm] is **not** defined.
```javascript
var v = ln( -4.0 );
// returns NaN
```
## Examples
```javascript
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var ln = require( '@stdlib/math/base/special/ln' );
var x;
var i;
for ( i = 0; i < 100; i++ ) {
x = round( randu() * 100.0 );
console.log( 'ln(%d) = %d', x, ln( x ) );
}
```
[natural-logarithm]: https://en.wikipedia.org/wiki/Natural_logarithm