note 80939 deleted from function.round by danbrown
| From: | danbrown@php.net | Date: | Sun, 17 May 2009 16:15:49 +0000 |
| Subject: | note 80939 deleted from function.round by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-154779@lists.php.net to get a copy of this message | ||
Note Submitter: altsoph
----
Another way to code all 7 rounding methods according IEEE754 standart:
<?php
// We need precision parameter for ceil & floor
function p_ceil( $val, $d )
{
return ceil($val * pow (10, $d) )/ pow (10, $d) ;
}
function p_floor( $val, $d )
{
return floor($val * pow (10, $d) )/ pow (10, $d) ;
}
// We need signum
function sgn($x)
{
return $x ? ($x>0 ? 1 : -1) : 0;
}
// Now seven functions for standart rounding methods
function round_down($num, $d = 0)
{
return sgn($num)*p_floor(abs($num), $d);
}
function round_up($num, $d = 0)
{
return sgn($num)*p_ceil(abs($num), $d);
}
function round_half_even($num, $d = 0)
{
if( round($num,$d) == round_half_down($num,$d) )
return round($num,$d);
$pre_digit = round_down( $num, $d );
if( ($pre_digit/2) == round_down($pre_digit/2,$d) )
return round_down($num, $d);
else
return round_up($num, $d);
}
function round_ceiling($num, $d = 0)
{
return p_ceil($num, $d);
}
function round_floor($num, $d = 0)
{
return p_floor($num, $d);
}
function round_half_down($num, $d = 0)
{
return ((2*round_up($num,$d)==round_up(2*$num,$d))
? round($num,$d) : round_down($num,$d) );
}
function round_half_up($num, $d = 0)
{
return round($num, $d);
}
?>
My article (in Russian) about rounding in PHP is here:
http://altsoph.ru/?p=521