INSTALLING anuga_parallel

anuga_parallel

Well first you need to get the anuga_parallel code. You can get this from our svn repository with userid anonymous (blank password)

The location is ​https://anuga.anu.edu.au/svn/anuga/trunk/anuga_core/source/anuga_parallel

(By the way, the most recent version of the development code of anuga is available at ​https://anuga.anu.edu.au/svn/anuga/trunk/anuga_core/source/anuga )

Setup your PYTHONPATH to point to location of the source directory

For instance I have the following line in my .bashrc file

export PYTHONPATH=/home/steve/anuga/anuga_core/source

MPI

Now you need to install MPI on your system. OPENMPI and MPICH2 are supported by pypar (see below) so both should be ok.

Make sure mpi works. You should be able to run a program in parallel. Try something as simple as

mpirun -np 4 pwd

should produce the output of pwd 4 times.

PYPAR

We use pypar as the interface between mpi and python. The most recent version of PYPAR is available from ​http://code.google.com/p/pypar/

(There is an old version on sourceforge ​http://sourceforge.net/projects/pypar/ don't use that)

Install pypar following the instructions in the download. You should be able use the standard command

python setup.py install

or maybe

sudo python setup.py install

Make sure the pypar examples work

PYMETIS

In the anuga_parallel directory there is a subdirectory pymetis.

Follow the instructions in README to install. Essentially just run make.

If you have a 64 bit machine run

make COPTIONS="-fPIC"

From the pymetis directory, test using test_all.py, ie

python test_all.py

ANUGA_PARALLEL

Should now be ready to run some parallel anuga code. Go back to the anuga_parallel directory and run test_all.py

Hopefully that all works.

Example program

Run run_parallel_sw_merimbula.py

First just run it as a sequential program, via

python run_parallel_sw_merimbula.py

Then try a parallel run using a command like

mpirun -np 4 python run_parallel_sw_merimbula.py

That should run on 4 processors

You should look at the code in run_parallel_sw_merimbula.py

Essentially a fairly standard example, with the extra command

domain = distribute(domain)

which sets up all the parallel stuff.

Also for efficiency reasons we only setup the original full sequential mesh on processor 0, hence the statement

if myid == 0:
     domain = create_domain_from_file(mesh_filename)
     domain.set_quantity('stage', Set_Stage(x0, x1, 2.0))
else:
     domain = None

The output will be an sww file associated to each processor.

There is a script anuga/utilities/sww_merge.py which provides a function to merge sww files into one sww file for viewing with the anuga viewer.

Suppose your parallel code produced 3 sww files, domain_P0_3.sww domain_P1_3.sww and domain_P2_3.sww

The base name would be "domain" and the number of processors would be 3. To stitch these 3 files together either run the sww_merge.py as a script with the command

python /dir_to_anuga/utilities/sww_merge.py -f domain -np 3

or add the following command at the end of your simulation script

domain.sww_merge()