ARPACK situation

[Jordi Gutiérrez Hermoso]

(Mass email, please hit reply-all to keep everyone abreast of the
situation. May get some bounces from mailing lists.)

I'm writing this email to discuss the future of ARPACK. The problem is
this: it's a widely-used library, but it seems abandoned upstream (and
upstream, to whom this is addressed, can confirm or deny). This has
resulted in the problem of many mini-forks as each organisation
distributes ARPACK patches its own way, and very often, for the same
bugs. These are the ones I could find:

     http://hg.savannah.gnu.org/hgweb/octave/file/tip/libcruft/arpack/
     http://patch-tracker.debian.org/package/arpack/2.1+parpack96.dfsg-3
     https://github.com/inducer/arpack
     http://mathema.tician.de/software/arpack
     http://dev.gentoo.org/~bicatali/
     
http://pkgs.org/centos-5-rhel-5/epel-x86_64/arpack-2.1-13.el5.x86_64.rpm.html
     
https://github.com/scipy/scipy/tree/fa21e840ad69fbac7ff600a7ef2b36929c18b975/scipy/sparse/linalg/eigen/arpack
     
http://bazaar.launchpad.net/~igraph/igraph/0.5-main/files/1139.1.143/src/arpack/

Additionally, the Mathworks (they make Matlab) probably also has their
own version of ARPACK, but I wasn't able to find a public version of
it, nor an email to send them questions to. If someone could contact
them, it would be nice to let them know.

These all seem to have modified ARPACK in some way, with minor or
major bugfixes, and as far as I can tell, have mostly done so
independently. To me, this seems like unnecessary work, if we're all
patching the library again and again and making our own private forks.
What I therefore propose is to have some sort of central location for
it and we all pool our efforts on this one location. I think it would
be easiest to use Andreas Klöckner's existing fork on github, since
this requires the least maintenance and work from anyone. All that it
requires for now is for each of the people above to see what patches
they have made and transplant them to the git repo.

It would be helpful if upstream could confirm that they are happy with
ARPACK development continuing on github and mention this on the ARPACK
webpage, so that new people who are interested on ARPACK can be
redirected.

Thanks,
- Jordi G. H.
  GNU Octave developer