Hi Nick,
thanks for your contribution.
I think there is no general answer to your question. It depends if it
is a disadvantage of running the mpi-version with 1 MPI process over
running the serial version. I imagine that LAMMPS enable some special
optimization if mpi is disabled as it can assume that everything
happens locally and no mpi message need to be send. On the other hand,
if the build of LAMMPS takes hours, one might prefer building it only
once. Do LAMMPS offer other palatalizations like OpenMP or Threads to
use multiple cores?
>From a brief look at our patch I see the following issues:
- I am not sold on this Makefile patch and patching of the patch
approach, seems a bit fragile. It might be better to use the default
gcc Makefile and patch that. I prefer adding CC,CFLAGS etc, on emake
comandline, you could create a function to avoid writing it on every
emake call. (my_emake() { emake "$@" CC= CFLAGS=; } )
- sed calls need to secured with "|| die"
- DEPEND should be static, DEPEND="mpi? ( vitrual/mpi )" should do it
- virtual/fortran is missing in DEPEND or use fortran-2.eclass and
FORTRAN_NEEDED="fortran" instead.
- lammps-gzip enables normal gzip support, so the use flags should be
called gzip.
If you are unsure about some technical details in an ebuild, create a
pull request on github and somebody will give you advice in the
review.
Otherwise good job, looking forward to more commits from you,
Christoph
2013/5/12 Nicolas Bock <[email protected]>:
> Hi,
>
> I recently added a lammps ebuild to the science overlay. It so far only
> builds the serial version, and has very limited support for build time
> options. I now added the mpi use flag and changed the ebuild so that it
> builds the mpi version. I have attached a patch against master that does
> this. I would like to get some feedback on those changes. Are they
> acceptable in this form? What should I have done differently? How would I go
> about writing an ebuild that builds both, the serial _and_ the mpi version
> in case the mpi use flag is set?
>
> Thanks already,
>
> nick
>
--
Christoph Junghans
http://dev.gentoo.org/~ottxor/
