[Numpy-discussion] Recent work for branch cuts / C99 complex maths: problems on mingw

David Cournapeau david@ar.media.kyoto-u.ac...
Tue Jul 29 06:16:36 CDT 2008

Pauli Virtanen wrote:
> I'm not sure whether it makes sense to keep the C99 tests in SVN, even if 
> marked as skipped, before the C code is fixed. Right now, it seems that 
> we are far from C99 compliance with regard to corner-case value inf-nan 
> behavior. (The branch cuts are mostly OK, though, and I suspect that what 
> is currently non-C99 could be fixed by making nc_sqrt to handle negative 
> zeros properly.)

Is there a clear explanation about C99 features related to complex math
somewhere ? The problem with C99 is that few compilers implement it
properly. None of the most used compilers implement it entirely, and
some of them don't even try, like MS compilers; the windows situations
is the most problematic because the mingw32 compilers are old, and thus
may not handle than many C99 features. There are also some shortcuts in
the way we detect the math functions, which is not 100 % reliable
(because of some mingw problems, in particular: I have already mentioned
this problem several times, I really ought to solve it at some points
instead of speaking about it).

So what matters IMHO is the practical implications with the compilers/C
runtime we use for numpy/scipy (gcc, visual studio and intel compilers
should cover most of developers/users).



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