log1p
(PHP 4 >= 4.0.7, PHP 5)
log1p — Returns log(1 + number), computed in a way that is accurate even when the value of number is close to zero
說明
float log1p
( float $number
)
Warning
本函式是實驗性的。這個函式的行為、名稱、和關於此函式的任何其他文件在未來PHP的發行中可能會在不通知的情況下改變。 使用此函式需自行承擔風險。
log1p() returns log(1 + number ) computed in a way that is accurante even when the value of number is close to zero. log() might only return log(1) in this case due to lack of precision.
Note: 本函式未在 Windows 平台下實作。
參數
- number
-
The argument to process
Return值
log(1 + number )