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Introduction to MPI - Exercise II Write a parallel program using MPI to add sum the elements of an array of integers, using Broadcast and Gather 1. Copy the file add.c from /home/appl/mpiworkshop to a directory called "mpiworkshop" under your home directory.2. Examine, compile, and execute the add.c program on one node. cat add.c mpicc add.c OR /usr/local/apps/mpich-1.2.5/bin/mpicc add.c 3. Copy the partially developed parallel program add_mpi.c from /home/appl/mpiworkshop to a directory called "mpiworkshop" under your home directory. 4. Edit add_mpi.c by following the instructions in CAPITAL LETTERS in the comments of the program. 5. Copy add_mpi.pbs from /home/appl/mpiworkshop to your working directory and examine/edit the lines containing mpich-1.2.4 and change them to mpich-1.2.5 or mpich-1.2.7p1 to compile and run add_mpi.c on 2 nodes. 6. Use qsub to submit the PBS job to PBS; qstat to monitor the job in the queue; and examine the PBS error/output files. 7. Run checkprocs_me to ensure you have stranded no processes on any nodes. 8. Modify the PBS job to run it on 4 nodes, and resubmit. 9. What happens when you run it on 3 nodes? OPTIONAL 10. Modify add_mpi.c so that it will still work correctly even if the number of processes/nodes does not evenly divide into the size of the array. | |
