[Debichem-devel] Bug#465723: mopac7 -- please do not use g2c.

[Daniel Leidert]

Am Montag, den 25.02.2008, 10:49 +0200 schrieb thassine at messi.uku.fi:

> in my opinion it's a good idea to use either FORTRAN or C version of MOPAC7.

Yeah. This is what I had in mind. f2c was AFAIK designed to compile
FORTRAN sources on systems, that do not have a FORTRAN compiler.

I would therefor suggest to prefer to compile the FORTRAN sources over
f2c generated C source compilation if a FORTRAN compiler is available.

> Many years earlier the use of f2c and C was the only way I could make this
> system work, so that's why it is like we have it now.

No problem.

> MOPAC7 is mostly fortran, plus some (system-related) C-files thrown in. So the
> FORTRAN compiler must be able to mix FORTRAN and C code, naturally.

One could write a test in configure.ac to compile a C and a FORTRAN
source file and link them together (this is something, where I could
need some help - will ask on the autoconf/automake lists if necessary).
A very simple alternative would be to add an option to force the
compilation of the C source (I guess, this will be necessary in every
case).

> But otherwise there is no reason why FORTRAN could not be used.

Sounds good to me.

> However, since I'm not really an expert FORTRAN programmer myself, and also
> because MOPAC7 is a very old (and also very famous!) program, I would like to
> be very very careful in making any changes in the program.

The current idea IMHO does not require to patch many things - probably
just a replacement of the s_copy function in fdate.c and the 3 fixes for
the issues I mentioned in my mail (patch now at [1]).

> And also I would
> like to keep the original, unmodified source in a separate directory in the
> package. So let's just maintain MOPAC7 very carefully...  :)

No problem for me. A ChangeLog should tell about the differences (where
we/you patched and why).

> To summarize, the idea is good, and I hope we can make it work ; please tell me
> if I can help. I'm not very good with those configuration tools but perhaps I
> can do testing etc.

I know the autotools pretty well and I will try to provide a patch for
upstream. However, I will be pretty busy till the end of April. So don't
expect the patch soon (maybe if I find some time) :)

Regards, Daniel