Dear all, I have some questions about parallel computing. For easy start I decided to try everything on 2-core Scientific Linux 5 Workstation.
The manual says PyTrilinos must be present, and Trilinos itself should be compiled with MPI support. Also, I think it's important, but is said only here http://matforge.org/fipy/wiki/SnowLeopardSourceBuild mpi4py must be present. After having all this I ran "mpirun -np 2 python setup.py test" and in fact the execution time increased by few percent, and not decreased as I expected, however, System Monitor showed the full load of 2 cores, as opposed to normal run when only 1 core is seen to be used. So behaved my own scripts - same (or slightly longer) execution time. The results of my scripts are same with or without mpirun, so it seems that mpirun runs 2 instances of the script on 2 cores in parallel, and not 1 instance with parallel execution (solution of the equation system). No errors or anything in the output. The questions I have: 1) What could be wrong? 2) How can I check which solvers (pysparse/pytrilinos) are used by fipy during the run? (Providing script with parameter --Trilinos or even some senseless to fipy any word did not change the result and did not throw an error. By the way, same was with FIPY_SOLVERS constant when I gave it different values within a script) 3) Do you have any idea how to check if Trilinos was compiled with MPI support? (it was installed by remote administrator) 4) If everything worked correct, would I really feel decrease of execution time of my scripts by factor of ~2 in my case? Regards, Igor.
