expm1

(PHP 4 >= 4.1.0, PHP 5)

expm1 --  Returns exp(number) - 1, computed in a way that is accurate even when the value of number is close to zero

Description

float expm1 ( float number )

警告

這個函數是實驗性質的。這個函數的行為、名稱、和關於此函數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。 使用此延伸需自行承擔風險。

expm1() returns the equivalent to 'exp(number) - 1' computed in a way that is accurate even if the value of number is near zero, a case where 'exp (number) - 1' would be inaccurate due to subtraction of two numbers that are nearly equal.

注: 此函數不適用於 Windows 平台。

See also log1p() and exp().