[Python-Dev] PEP 485 review (isclose())

[Guido van Rossum]

It should be written in C. I thought you knew. :-)

I guess it's okay to drop Decimal support (*). Complex support probably
should be in cmath.

But this is an amendmend to the PEP as accepted. If anyone cares about
these changes they should speak up, otherwise the PEP should be updated.

(*) Adding it to the decimal module would require a discussion with Raymond
Hettinger, but Decimal users can probably copy and paste the formula from
the PEP.

On Monday, March 2, 2015, Chris Barker <chris.barker at noaa.gov> wrote:

> On Fri, Feb 27, 2015 at 12:07 PM, Chris Barker <chris.barker at noaa.gov
> <javascript:_e(%7B%7D,'cvml','chris.barker at noaa.gov');>> wrote:
>
>> I'll edit the text as you suggest,
>>
>
> Done.
>
>
>> and then work on a patch -- I'm sure I'll have questions for Python-dev
>> when I actually do that, but I'll get started on my  own and see how far I
>> get.
>>
>
> OK --  big question 1:
>
> As far as I can tell, the math module is entirely a C extension. So I can:
>
> 1) write isclose() in C -- I could probably do that (It's been a while --
> I'm a big Cython fan these days...) and I'd probably punt on having it work
> with anything other than floats if I did that -- which would fit how most
> of the match module works anyway.
>
> 2) Write it in Python, and monkey-patch it in to the math module -- I
> honestly have no idea how to do that, but as I can add a new name to the
> math module after importing it, it should be doable --but I have no idea
> where the code would go.
>
> Suggestions??
>
> Thanks,
>   -Chris
>
>
>
>
>
>
>
>
>> -Chris
>>
>>
>>
>>
>>
>> On Fri, Feb 27, 2015 at 11:38 AM, Guido van Rossum <guido at python.org
>> <javascript:_e(%7B%7D,'cvml','guido at python.org');>> wrote:
>>
>>> I think it's time to accept PEP 485. I've re-read it once more, and it
>>> looks like the text is in great shape. (My only recommendation would be to
>>> update the Abstract to state that we're specifically adding math.isclose().)
>>>
>>> A wording question: "This implementation has a flag that lets the user
>>> select which relative tolerance test to apply -- this PEP does not suggest
>>> that that be retained, but rather than the weak test be selected." -- I
>>> think this was meant to say "... rather *that* the weak test be selected",
>>> right? (It would be nice if the sample implementation defaulted to the
>>> choice in the PEP.)
>>>
>>> However, those are just minor edits, and I hereby approve the PEP.
>>> Thanks Chris and everyone else for the fruitful discussion (and thanks
>>> especially to Chris for eventually ending the bikeshedding and writing a
>>> PEP that explains each of the choices). Congrats!
>>>
>>> --
>>> --Guido van Rossum (python.org/~guido)
>>>
>>
>>
>>
>> --
>>
>> Christopher Barker, Ph.D.
>> Oceanographer
>>
>> Emergency Response Division
>> NOAA/NOS/OR&R            (206) 526-6959   voice
>> 7600 Sand Point Way NE   (206) 526-6329   fax
>> Seattle, WA  98115       (206) 526-6317   main reception
>>
>> Chris.Barker at noaa.gov
>> <javascript:_e(%7B%7D,'cvml','Chris.Barker at noaa.gov');>
>>
>
>
>
> --
>
> Christopher Barker, Ph.D.
> Oceanographer
>
> Emergency Response Division
> NOAA/NOS/OR&R            (206) 526-6959   voice
> 7600 Sand Point Way NE   (206) 526-6329   fax
> Seattle, WA  98115       (206) 526-6317   main reception
>
> Chris.Barker at noaa.gov
> <javascript:_e(%7B%7D,'cvml','Chris.Barker at noaa.gov');>
>


-- 
--Guido van Rossum (on iPad)
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