[firedrake] Installing Firedrake on an HPC machine

[Lawrence Mitchell]

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On 06/08/15 15:42, Justin Chang wrote:
>> mpiexec -n 2 python run-pyop2.py
> 
> --------------------------------------------------------------------------
>
>  An MPI process has executed an operation involving a call to the
> 
> "fork()" system call to create a child process.  Open MPI is
> currently
> 
> operating in a condition that could result in memory corruption or
> 
> other system errors; your MPI job may hang, crash, or produce
> silent
> 
> data corruption.  The use of fork() (or system() or other calls
> that
> 
> create child processes) is strongly discouraged.
> 
Huh, OK.

I was expecting this to work!  To confirm, run-pyop2.py just contains:

from pyop2 import op2
op2.init()

Can you edit some files in PyOP2 just to check what's going on:

In PyOP2/pyop2/__init__.py

Replace:

from pyop2_utils import enable_mpi_prefork

with:

print 'init pyop2'
from pyop2_utils import enable_mpi_prefork

In PyOP2/pyop2/mpi.py

Replace:

from decorator import decorator

with:

print 'init mpi'
from decorator import decorator

In PyOP2/pyop2_utils/__init__.py

Replace:

        prefork.enable_prefork()

with:

        print 'forking'
        prefork.enable_prefork()


And then try running run-pyop2.py on just one MPI process.

I see:

init pyop2
forking
loading mpi


But maybe you get something else?

And then let's test if the following works:

cat > manual-fork.py << EOF
from pyop2_utils import enable_mpi_prefork
enable_mpi_prefork()
from firedrake import *
from mpi4py import MPI
print MPI.COMM_WORLD.size
EOF
mpiexec -n 2 python manual-fork.py

Cheers,

Lawrence

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