#40039: New port: mumps 4.10.0 - a library for solving sparse linear systems -------------------------+-------------------------------- Reporter: wimmer@… | Owner: macports-tickets@… Type: submission | Status: new Priority: Normal | Milestone: Component: ports | Version: 2.2.0 Resolution: | Keywords: Port: | -------------------------+-------------------------------- Comment (by wimmer@…): Replying to [comment:7 sean@…]:
Replying to [comment:6 wimmer@…]:
- Mumps has the orderings it can use defined at compile-time (with -Dparmetis etc.). For a variant you'd want to use mostly in parallel, this means you want to compile it with the parallel parmetis and ptscotch. Now, assuming you can use the parallel version also in sequential mode by linking mpiseq, you still would have to link against parmetis and ptscotch although in the sequential version you wouldn't ever use it. Now, one could presumably fix this by adding dummy parmetis/ptscotch wrappers to mpiseq, but that's even more patching
[[BR]] Dummy wrappers for parmet… what? You can compile all the optional orderings and decide on which one to use at run-time. You can also compile MUMPS for parallel and use its sequential algorithm at run-time. As homework, you can try it out: [[BR]]
* running mpi-mumps + parmetis with 'mpiexec -n 1 ./test_prog' * running mpi-mumps + ptscotch with 'mpiexec -n 1 ./test_prog' * running mpi-mumps + parmetis with 'mpiexec -n 2 ./test_prog' * running mpi-mumps + ptscotch with 'mpiexec -n 2 ./test_prog' * running mpi-mumps + internal ordering with 'mpiexec -n 1 ./test_prog' * running mpi-mumps + internal ordering with 'mpiexec -n 2 ./test_prog'
And then try all of that again with sequentially built MUMPS.
Sure you can do that, but this wasn't my point. My point was that after you specified for which orderings MUMPS is built by specifying any combination of "-Dpord -Dmetis -Dparmetis -Dscotch -Dptscotch", you have to always link against all of these libraries. Now, it is worth noting that the parmetis switch does not include all of the functionality of the metis switch, as MUMPS offers more functionality when only sequential analysis is used (see documentation of the ICNTL(28) parameter). Hence, one would like to include both parmetis and metis at the same time anyways (I noticed that your Portfile only had parmetis included). If a user would want to use the sequential version, there is not reason for him to use the parallel analysis at all (it gives no additional functionality, but even reduces it), but he/she would always need to link against parmetis/ptscotch. This is, in my opinion, a good reason to have separate sequential and parallel versions. That in addition to the fact that while I believe that it is probably possible to use the parallel version in sequential mode without mpi (by linking against mpiseq and dealing with different mpi's properly), the MUMPS web page does advocate separate sequential and parallel versions (http://graal.ens-lyon.fr/MUMPS/index.php?page=faq#5).
What's so bad about having both a sequential and a parallel version installed (from the same Portfile)? This is how Debian does it, so it's kind of a standard (with the sequential version having a trailing _seq in the library name)
[[BR]] Well, for one, I don't like having an unnecessary port (sequential MUMPS) since all its functionality would be provided by the parallel version.
I was mostly thinking about people wanting to compile software that uses metis v4 - those wouldn't want to patch everything themselves. (even for macports, if you can avoid patching stuff, I think it's better, with every patch you can make a mistake).
[[BR]] Instead of a hypothetical situation, do you have any examples? I have updated most of the ports (in my side repo) to use the newest version of MeTiS / ParMeTiS but might have missed some. Since it's a very, very simple change (usually two lines of code change), I would rather push others to update their code.
I don't have a particular example (except MUMPS itself), but suppose I want to install versions of Mumps, SuiteSparse, SuperLU, ... not provided by macports - then I have to do the patching myself (or manually install metis 4). Metis 4 was the standard for more than 10 years when there was no development there; scientific codes are usually conservative in that you don't want to touch what works, so people do not easily change to metis 4 (look at Mumps and SuiteSparse). -- Ticket URL: <https://trac.macports.org/ticket/40039#comment:8> MacPorts <http://www.macports.org/> Ports system for OS X