Re: [pure-lang-users] complex 0

[Albert G. <Dr....@t-...>]

Eddie Rucker wrote:
> I know I'm the one that brought this up, but how about we revisit the
> issue later when we have time to think about this.

Well, in any case it was bad to have these two cases return inconsistent 
results, so I fixed that now in the way I described. Making it conform 
with the ISOC99 recommendations is now just a matter of editing the two 
rules for complex * and /, if we lateron decide that we need that.

> Later, we can compare Pure results to GSL's
> results. I think consistency with GSL should be a must.

The only way to achieve 100% compatibility with GSL there would be to 
actually use the complex multiplication and division routines employed 
by GSL itself. But presumably GSL just uses whatever complex arithmetic 
the C compiler provides (or Fortran, in the case of BLAS). In the case 
of the GNU compilers (which are the ones we use on all major platforms 
except the *BSDs) the results should be compatible with what math.pure 
provides now.

An alternative would be to actually use the complex double routines 
provided by the C runtime and library, and add marshalling of complex 
results to the C interface. That would be useful to have anyway, for 
interfacing to GSL. I'll have a look at that in the next release.

> I'll note math things that look funny and we can hash them later. I'll
> just report other types of errors for now.

Ok, thanks.

Albert

-- 
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email:  Dr....@t-..., ag...@mu...
WWW:    http://www.musikinformatik.uni-mainz.de/ag