Re: ARPACK sources removed from Octave

[John W. Eaton]

On  4-Jan-2012, John W. Eaton wrote:

| On  4-Jan-2012, Rik wrote:
| 
| | Alas, the new test does not fail with a bad ARPACK library.  Is there a
| | reason to have the test written in Fortran and not C++?  The C++ version
| | was already debugged, but if we really want the configure test in Fortran
| | we can continue.
| 
| I did it to avoid issues of portability when mixing Fortran and C++.
| For example, you appended underscores to the Fortran names, but not
| all compilers do that.  You also used lower-case names, but some
| Fortran compilers use translate the Fortran function names to upper
| case.  Then there are different conventions for passing character
| strings.  So to make the test work for all Fortran compilers that
| might be used to compile ARPACK, we need to handle those issues.  It
| seemed simpler to just avoid all that and use an all Fortran test.

I thought about this some more and realized that there are three major
calling conventions for character arguments that we ever tried to
support: f2c, Cray/Unicos, and MSVF (look in libcruft/misc/f77-fcn.h).
Cray/Unicos is probably not a major issue now.  I don't know that MSVF
was ever tested.  We don't have a configure test to enable it
automatically.  So I checked in the following change:

  http://hg.savannah.gnu.org/hgweb/octave/rev/71e28fda7be9

It causes a configure failure on my Debian system that disables
ARPACK.  Testing your program by hand and linking it with the ARPACK
library that we were previously distributing works, so I think the
test is OK.

Now the question is whether distributions will package the new ARPACK
library so that Octave will be fully functional.

jwe