[Numpy-discussion] Binary ufuncs: minimum

Charles R Harris charlesr.harris@gmail....
Tue May 27 18:34:46 CDT 2008


On Tue, May 27, 2008 at 5:27 PM, Nathan Bell <wnbell@gmail.com> wrote:

> On Tue, May 27, 2008 at 5:39 PM, Christopher Barker
> <Chris.Barker@noaa.gov> wrote:
> >
> > I'm not so sure. I know I wouldn't expect to get a different type back
> > with a call to abs(). Do we really want to change that expectation just
> > for the case of MIN_INT?
> >
> > While everyone is going to want an unsigned value when calling abs(),
> > who knows if they might want to use negative numbers later? Like:
> >
> > x = abs(x)
> > x *= -1
> >
> > Now what do we get/want?
>
> IMO abs() returning non-negative numbers is a more fundamental
> property.  In-place operations on integer arrays are somewhat
> dangerous, and best left to more sophisticated users anyway.
>
>
> Interestingly, MATLAB (v7.5.0) takes a different approach:
>
> >> A = int8([ -128, 1])
> A =
>  -128    1
> >> abs(A)
> ans =
>  127    1
> >> -A
> ans =
>  127   -1
>
>
Oooh, talk about compromises...

Chuck
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