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

[David Cournapeau]

Charles R Harris wrote:
>
>
> On Mon, Jul 28, 2008 at 10:29 PM, David Cournapeau
> <david at ar.media.kyoto-u.ac.jp <mailto:david at ar.media.kyoto-u.ac.jp>>
> wrote:
>
>     Hi,
>
>        I was away during the discussion on the updated complex functions
>     using C99, and I've noticed it breaks some tests on windows (with
>     mingw;
>     I have not tried with Visual Studio, but it is likely to make things
>     even worse given C support from MS compilers):
>
>     http://scipy.org/scipy/numpy/ticket/865
>
>     Were those changes backported to 1.1.x ? If so, I would consider
>     this as
>     a release blocker,
>
>
> The only changes to the computations were in acosh and asinh, which I
> think should work fine. The tests check branch cuts and corner cases
> among other things and are only in the trunk, so we aren't any worse
> off than we were, we just have more failing tests to track down.

Ok. I though there was more than just tests, but also C code
modification. If not, it is certainly much less of a problem.

> At least one previous failing tests looked to be a Python bug, so
> finding the root causes here and putting together tests that work
> everywhere is going to be a project. Some of the problems could be in
> the windows library, probably sqrt and log.

One thing is that mingw now uses ancient gcc (3.4.5), and there was a
lot of changes since then for C99 conformance. We can just pretend the
problem is not there for now, but for 2.6, we will have to handle this,
because mingw with gcc 3.4 does not have a runtime compatible with MSVC
9, which is the one used by python2.6 binary release. That will be a lot
of fun :)

cheers,

David