Bug #15946 Updated: Math output errors

ID: 15946 Updated by: php-bugs@lists.php.net Reported By: aubieweb@rogers.com -Status: Feedback +Status: No Feedback Bug Type: Math related Operating System: Windows 2000 PHP Version: 4.1.1 New Comment: No feedback was provided for this bug for over a month, so it is being suspended automatically. If you are able to provide the information that was originally requested, please do so and change the status of the bug back to "Open". Previous Comments: ------------------------------------------------------------------------ [2002-03-08 16:52:22] aubieweb@rogers.com OK. I added a bunch of round()'s around the variables and the problem seems to have been fixed up to 48 rows. This just seems to be numbers start loosing accuracy after a while. Even smaller numbers. ------------------------------------------------------------------------ [2002-03-08 07:19:23] aubieweb@rogers.com Yes. Here is the exact code that shows the calculuation. $check = $num % $divisor; if ($hidenum && $divisor > 0 && $num % $divisor == 0) print "<td><img src='red.gif' width='$size' height='$size' alt='$num % $divisor = $check'></td>\n"; As yuo can see, the calculation is very simple (top line) and the alt of the image shows both numbers exactly and they haven't been changed. In that piece of code I get the bad results but only AFTER the loop has been running for some time. ------------------------------------------------------------------------ [2002-03-08 06:27:19] sander@php.net (reclassified) ------------------------------------------------------------------------ [2002-03-08 06:20:38] sander@php.net Are you completely sure that it's an error in PHP and not in your algorithm? ------------------------------------------------------------------------ [2002-03-07 22:55:18] aubieweb@rogers.com I wrote a script which output Pascal's triangle and then showed the numbers which were divisible by a certain number in a different colour. At first, this works fine. Then after the 20th row or so, the % operator starts outputting incorrect numbers. For example, 37 % 4 returns 1. 24 % 4 returns 3. When those numbers are checked on their own, it works fine. In the loops though, it starts giving incorrect information after 20 rows. You can see this at www.alkaline2.com/triangle.php CODE <? $rows--; for ($r = 0; $r <= $rows; $r++) { if ($hidenum) print "<table cellpadding='0' cellspacing='0' border='1' bordercolor='#000088' borderstyle='solid'><tr>\n"; if (!$hidenum) print "<table cellpadding='2' cellspacing='1' border='0'><tr>\n"; for ($i = 0; $i <= $r; $i++) { $num = factorial($r)/(factorial($r - $i) * factorial($i)); if ($divisor > 0 && $num % $divisor == 0) { $bgcolor='#ff0000'; } else { $bgcolor='#444444'; } if (!$hidenum) print "<td bgcolor='$bgcolor'><span class='text'>$num</span></td>\n"; $check = $num % $divisor; if ($hidenum && $divisor > 0 && $num % $divisor == 0) print "<td><img src='red.gif' width='$size' height='$size' alt='$num % $divisor = $check'></td>\n"; if ($hidenum && $divisor > 0 && $num % $divisor != 0) print "<td><img src='grey.gif' width='$size' height='$size' alt='$num % $divisor = $check'></td>\n"; if ($hidenum && $divisor == 0) print "<td><img src='grey.gif' width='$size' height='$size' alt='$num % $divisor = $check'></td>\n"; } print "</tr></table>"; } function factorial($x) { $total = 1; for ($i = $x; $i > 1; $i--) $total = $total * $i; return $total; } ?> ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=15946&edit=1