Edit report at http://bugs.php.net/bug.php?id=52894&edit=1
ID: 52894
Updated by: ras...@php.net
Reported by: info at tellmatic dot org
Summary: number_format fails with large values
Status: Bogus
Type: Bug
Package: *Math Functions
Operating System: linux
PHP Version: 5.2.14
Block user comment: N
New Comment:
Yes, that is all number_format does. But, you asked it for 50 digits of
precision for 1234.560000 which just isn't possible for computers to
represent
given the way they they handle floating point numbers. It has nothing
to do
with number_format. You will see the same if you do:
ini_set('precision',50);
echo 1234.560000;
If you need super-precise floating point, you can't use the computers
built-in
floating point support. You will need to use http://php.net/gmp
instead. The
big drawback is that it is much much slower than the computer's native
floating
point support.
Previous Comments:
------------------------------------------------------------------------
[2010-09-21 14:48:49] info at tellmatic dot org
number_format should 'format' numbers, not recalculate, or? thats how i
understand the function.
------------------------------------------------------------------------
[2010-09-20 18:24:37] ras...@php.net
Floating point values have a limited precision. Hence a value might
not have the same string representation after any processing. That also
includes writing a floating point value in your script and directly
printing it without any mathematical operations.
If you would like to know more about "floats" and what IEEE
754 is, read this:
http://docs.sun.com/source/806-3568/ncg_goldberg.html
Thank you for your interest in PHP.
.
------------------------------------------------------------------------
[2010-09-20 17:53:57] info at tellmatic dot org
Description:
------------
wrong output, not as give, drifts a lot!
Test script:
---------------
number_format("1234.560000", 50, '.', '');
Expected result:
----------------
expected output should be 1234.56 with additional 48 zeros! and not a
'random value'.
Actual result:
--------------
== 1234.55999999999994543031789362430572509765625000000000
????
can't be!
------------------------------------------------------------------------
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Edit this bug report at http://bugs.php.net/bug.php?id=52894&edit=1
