(PHP 4, PHP 5)
log — Natural logarithm
If the optional base parameter is specified, log() returns logbase arg, otherwise log() returns the natural logarithm of arg.
The value to calculate the logarithm for
The optional logarithmic base to use (defaults to 'e' and so to the natural logarithm).
The logarithm of arg to base, if given, or the natural logarithm.
| Версия | Описание |
|---|---|
| Since 4.3.0 | The optional parameter base became available. For older versions you can calculate the logarithm in base b of a number n, but using the mathematical identity: logb(n) = log(n)/log(b), where log is the neperian (or natural) logarithm. |