From: [EMAIL PROTECTED]
Operating system: Solaris 7
PHP version: 4.3.0
PHP Bug Type: Math related
Bug description: round error
<?
$a=4.31;
$b=5;
$m=$a*$b ;
$res=21.55 ;
$v1=round(4.31*5,1);
$v2=round($m,1) ;
$v3=round($a*$b,1) ;
$v4=round($res,1) ;
$vbiz=round($a*$b,2) ;
$r=$v2-$v1 ;
$r2=$v3-$v1 ;
$r3=$res-$m ;
print ("<b>a=-$a- b=-$b- m=$a*$b=-$m- and res=$res") ."-<br></b>" ;
print ("v1=round(4.31 * 5 , 1)=-$v1- -") . round($v1,1) ."-<br>" ;
print ("v2=round(m, 1)=-$v2- -") . round($v2,1) ."-<br>" ;
print ("v3=round(a*b , 1)=-$v3- -") . round($v3,1) ."-<br>" ;
print ("v4=round(res , 1)=-$v4- -") . round($v4,1) ."-<br>" ;
print ("expected round by 2 round... <br>") ;
print ("vbiz=round($a*$b ,2)=$vbiz -- and round($vbiz, 1)=") .
round($vbiz,1) ."<br><br>" ;
print ("r=$v2-$v1=$r -good-<br>") ;
print ("r2=$v3-$v1=$r2 -good-<br>") ;
print ("unexpected result... <br>") ;
print ("r3=$res-$m=$r3 -Huh ?-<br>") ;
?>
will give that output
a=-4.31- b=-5- m=4.31*5=-21.55- and res=21.55-
v1=round(4.31 * 5 , 1)=-21.5- -21.5-
v2=round(m, 1)=-21.5- -21.5-
v3=round(a*b , 1)=-21.5- -21.5-
v4=round(res , 1)=-21.6- -21.6-
expected round by 2 round...
vbiz=round(4.31*5 ,2)=21.55 -- and round(21.55, 1)=21.6
r=21.5-21.5=0 -good-
r2=21.5-21.5=0 -good-
unexpected result...
r3=21.55-21.55=3.5527136788005E-15 -Huh ?-
--
Edit bug report at http://bugs.php.net/?id=21769&edit=1
--
Try a CVS snapshot: http://bugs.php.net/fix.php?id=21769&r=trysnapshot
Fixed in CVS: http://bugs.php.net/fix.php?id=21769&r=fixedcvs
Fixed in release: http://bugs.php.net/fix.php?id=21769&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=21769&r=needtrace
Try newer version: http://bugs.php.net/fix.php?id=21769&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=21769&r=support
Expected behavior: http://bugs.php.net/fix.php?id=21769&r=notwrong
Not enough info: http://bugs.php.net/fix.php?id=21769&r=notenoughinfo
Submitted twice: http://bugs.php.net/fix.php?id=21769&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=21769&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=21769&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=21769&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=21769&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=21769&r=gnused
