# [Numpy-discussion] Equvalent function for Ceil() and Floor()

Bakhtiyor Zokhidov bakhtiyor_zokhidov at mail.ru
Mon May 20 13:58:13 EDT 2013

``` ok... I think -0.0 is mathematically wrong but in a program it is true.

What I suspect is that if -0.0 doesn't affect on result (e.g., 2*(-0.0 + 2) or (-0.0-2)*2 ) . If it does not affect results it would be good for me
Thanks

Понедельник, 20 мая 2013, 9:03 -07:00 от Chris Barker - NOAA Federal <chris.barker at noaa.gov>:
>On Mon, May 20, 2013 at 8:54 AM, Bakhtiyor Zokhidov
>< bakhtiyor_zokhidov at mail.ru > wrote:
>
>> what about the following example:
>>>>>new_ceil(-0.24, 0.25)
>> -0.0
>
>ceil rounds toward +inf (and floor towards -inf) -- this is exactly
>what you want if you're doing what I think you are...(note that
>round() rounds towards and away from zero -- so different for negative
>numbers...)
>
>the minus sign means "minus 0.0", which is a seemingly odd floating
>point thing -- but FP numbers have a sign bit, which, in this case, is
>set to negative, even though, mathematically speaking, 0.0 doesn't
>have a sign. But it will compare to 0.0 as you'd expect:
>
>In [8]: -0.0 == 0.0
>Out[8]: True
>
>In [9]: -0.0 <  0.0
>Out[9]: False
>
>-Chris
>
>--
>
>Christopher Barker, Ph.D.
>Oceanographer
>
>Emergency Response Division
>NOAA/NOS/OR&R            (206) 526-6959   voice
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>
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