Bug in floating-point addition: is anyone else seeing this?

[bukzor]

On May 21, 11:38 am, Mark Dickinson <dicki... at gmail.com> wrote:
> On SuSE 10.2/Xeon there seems to be a rounding bug for
> floating-point addition:
>
> dickinsm at weyl:~> python
> Python 2.5 (r25:51908, May 25 2007, 16:14:04)
> [GCC 4.1.2 20061115 (prerelease) (SUSE Linux)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.>>> a = 1e16-2.
> >>> a
> 9999999999999998.0
> >>> a+0.999     # gives expected result
> 9999999999999998.0
> >>> a+0.9999   # doesn't round correctly.
>
> 10000000000000000.0
>
> The last result here should be 9999999999999998.0,
> not 10000000000000000.0.  Is anyone else seeing this
> bug, or is it just a quirk of my system?
>
> Mark

I see it too