Re: rounding_up

Hi, Tom!

> Round-to-nearest-even is a well-respected rule

Yes, you're convinced me! I can’t argue with IEEE 754 =) And, of course,
can’t break compatibility.


Best regards,

Daria Shanina

пн, 14 апр. 2025 г. в 17:26, Tom Lane <tgl@sss.pgh.pa.us>:

> Christoph Moench-Tegeder <cmt@burggraben.net> writes:
> > ## Daria Shanina (vilensipkdm@gmail.com):
> >> I noticed, when we parse and validate values (in particular, the int
> type),
> >> we use the *rint* method, but unfortunately it does not work according
> to
> >> the round rules.
>
> > First question would be "which round rule?" as (of course) there're
> > multiple to chose from.
>
> Yeah.  Round-to-nearest-even is a well-respected rule, which is why
> it's the default per IEEE 754.  I don't see a good reason for us
> to switch.  Even if someone advanced an argument, it would have
> to be a *mighty* convincing argument to justify breaking backwards
> compatibility here.
>
> I do find it a little unfortunate that our numeric type does it
> differently than our float types.  Again though, there's a huge
> compatibility argument against changing that now.  It does give
> you an "out" if you really need one or the other behavior for
> a particular application: you can cast to numeric or float8
> before casting to int.
>
>                         regards, tom lane
>


-- 
С уважением,
Шанина Дарья Александровна