# Logarithm
> Compute the base `b` [logarithm][logarithm].
## Usage
```javascript
var log = require( '@stdlib/math/base/special/log' );
```
#### log( x, b )
Computes the base `b` logarithm of `x`.
```javascript
var v = log( 100.0, 10.0 );
// returns 2.0
v = log( 16.0, 2.0 );
// returns 4.0
v = log( 5.0, 1.0 );
// returns Infinity
```
For negative `x` or `b`, the [logarithm][logarithm] is **not** defined.
```javascript
var v = log( -4.0, 1.0 );
// returns NaN
v = log( 2.0, -4.0 );
// returns NaN
```
## Examples
```javascript
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var log = require( '@stdlib/math/base/special/log' );
var b;
var x;
var i;
for ( i = 0; i < 100; i++ ) {
x = round( randu() * 100.0 );
b = round( randu() * 5.0 );
console.log( 'log( %d, %d ) = %d', x, b, log( x, b ) );
}
```
[logarithm]: https://en.wikipedia.org/wiki/Logarithm