[Python-ideas] Way to check for floating point "closeness"?

Neil Girdhar mistersheik at gmail.com
Thu Jan 15 22:52:21 CET 2015


The point is that this function is already in Python and if you want to do
something different, you should have a really good reason to do it
differently.  If you were to add a function to math, say math.close, it
should work like numpy.allclose in my opinion.

For reference, numpy does this:

absolute(*a* - *b*) <= (*atol* + *rtol* * absolute(*b*))

where atol is an absolute tolerance and rtol is a relative tolerance
(relative to the actual value b).  This subsumes most of the proposals here.

Best,

Neil

On Wed, Jan 14, 2015 at 7:48 PM, Chris Barker <chris.barker at noaa.gov> wrote:

> On Wed, Jan 14, 2015 at 4:23 PM, Neil Girdhar <mistersheik at gmail.com>
> wrote:
>
>> You might be interested in my question:
>>
>>
>> http://stackoverflow.com/questions/4028889/floating-point-equality-in-python
>>
>
> nothing new there, I'm afaid -- and no one seemed to have brought up the
> issue with zero.
>
> -Chris
>
>
> --
>
> Christopher Barker, Ph.D.
> Oceanographer
>
> Emergency Response Division
> NOAA/NOS/OR&R            (206) 526-6959   voice
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>
> Chris.Barker at noaa.gov
>
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