From: tny at eyefi dot nl
Operating system: Linix / BSDs
PHP version: 4.3.6
PHP Bug Type: Variables related
Bug description: Floating point error while adding values to a float var
Description:
------------
When adding a float value to a variable (starting with a negative value)
in a loop the result that should be zero (0) is nearly zero, but not exact
zero.
Reproduce code:
---------------
<?php
for ($i = -1.0; $i <= 1.0; $i += 0.1) {
echo $i . "\n";
}
?>
Expected result:
----------------
-1
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Actual result:
--------------
-1
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
-1.38777878078E-16
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
--
Edit bug report at http://bugs.php.net/?id=28542&edit=1
--
Try a CVS snapshot (php4): http://bugs.php.net/fix.php?id=28542&r=trysnapshot4
Try a CVS snapshot (php5): http://bugs.php.net/fix.php?id=28542&r=trysnapshot5
Fixed in CVS: http://bugs.php.net/fix.php?id=28542&r=fixedcvs
Fixed in release: http://bugs.php.net/fix.php?id=28542&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=28542&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=28542&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=28542&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=28542&r=support
Expected behavior: http://bugs.php.net/fix.php?id=28542&r=notwrong
Not enough info: http://bugs.php.net/fix.php?id=28542&r=notenoughinfo
Submitted twice: http://bugs.php.net/fix.php?id=28542&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=28542&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=28542&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=28542&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=28542&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=28542&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=28542&r=float
