[petsc-users] petsc-users Digest, Vol 16, Issue 23

[Aron Ahmadia]

Dear Zhisong,

Jed asked you to use the makefile to actually launch the test, as so:

cd src/snes/examples/tutorials && make -n runex5

You'll notice in your reply that you only built ex5, and didn't use the make
command to launch the job.  This is important to ensure that you can execute
your code in parallel using the MPI that PETSc detected or installed.

"All the machines have mpi package installed before I got to touch PETSc.
That might be the potential problem. But "Portability" is one of the main
features of PETSc. Doesn't that mean the user can run the final executable
anywhere as long as c and mpi libraries are available?"

Traditionally, portability means that the code will compile and link
anywhere, not that you can drag and drop executables as you wish.  You are
responsible for re-building PETSc applications or at least ensuring binary
and MPI compatibility.

Hope this helps...

Warm Regards,
Aron Ahmadia

On Mon, Apr 19, 2010 at 11:05 PM, Li, Zhisong (lizs) <lizs at mail.uc.edu>wrote:

> Mat and Jed,
>
> Thank you for your reply.
>
> As far as I remembered, the make test was successful except the Fortran
> complier, but I only use C for my work.
>
> I tried " $ cd src/snes/examples/tutorials && make -n ex5" and it shows:
> /home/lizs/petsc/linux-gnu-c-debug/bin/mpicc  ex5.c  -o  ex5
>
> All the machines have mpi package installed before I got to touch PETSc.
> That might be the potential problem. But "Portability" is one of the main
> features of PETSc. Doesn't that mean the user can run the final executable
> anywhere as long as c and mpi libraries are available?
>
> Thanks,
>
> Zhisong Li
>
>
> ________________________________________
> Subject: petsc-users Digest, Vol 16, Issue 23
>
>
> The mpiexec in your path is not the one you configured with. What
> MPI is begin used?
>
>   Matt
>
>
> > > I've tried to run some PETSc examples and my own simple PETSc codes on
> my
> > > office's cluster as well as on Ohio Supercomputer Center's machine. At
> first
> > > I found no speedup for parallel processing and later I noticed by
> checking
> > > the rank that actually each node is doing the same sequential
> processing.
> > > I'm sure the codes are parallel codes (such as ex19.c in SNES and ex7.c
> in
> > > TS tutorial codes). Is there anything I am missing in the installation
> or
> > > the run command such as"mpiexec -n 3 ex7"? How can I realize a parallel
> > > running?
> > >
> >
> > The mpiexec in your path is not the one you configured with. What
> > MPI is begin used?
>
> Does make test run successfully?  If so, then
>
>  $ cd src/snes/examples/tutorials && make -n runex5
>
> will tell you which mpiexec PETSc is using.
>
> Jed
>
>
>
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