note 29752 modified in function.expm1 by danbrown
| From: | danbrown@php.net | Date: | Tue, 09 Mar 2010 12:08:54 +0000 |
| Subject: | note 29752 modified in function.expm1 by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-166813@lists.php.net to get a copy of this message | ||
Compare this to log1p (which is its inverse).
Also, You may have to use a similar workaraound in case the underlying C library
does not support expm1:
<?php
function expm1($x) {
return ($x>-1.0e-6 && $x<1.0e-6) ? ($x + $x*$x/2) : (exp($x)-1);
}
?>
--was--
Compare this to log1p (which is its inverse).
Also, You may have to use a similar workaraound in case the underlying C library
does not support expm1:
function expm1($x) {
return ($x>-1.0e-6 && $x<1.0e-6) ? ($x + $x*$x/2) : (exp($x)-1);
}
http://php.net/manual/en/function.expm1.php