Parallel Programming

Hello是個mpi-aware的平行程式，當在單一主機上執行指令:

mpirun -np 4 ./Hello

會出現下現訊息:

It seems that [at least] one of the processes that was started with mpirun did not invoke MPI_INIT before quitting (it is possible that more than one process did not invoke MPI_INIT -- mpirun was only notified of the first one, which was on node n0).

亦即MPI_Init只會被head-node來invoke一次，之後就由head-node來派送task，到不同的worker-nodes上。

mpirun can *only* be used with MPI programs (i.e., programs that invoke MPI_INIT and MPI_FINALIZE). You can use the "lamexec" program to run non-MPI programs over the lambooted nodes.

如果使用lamexec來執行mpi-aware的程式，就沒有問題。

#Tuesday, February 07, 2006 posted by samuel @ 6:02 PM 0 comments

在Ubuntu-5.10安裝了libmpich1.0, libmpich1.0-dev(含有檔頭mpi.h)，以及mpich-bin(含有mpirun)，mpi-doc(含有wegpages, Shared Memory的pdf檔, manpages...等等)

現在要學的MPICH，己經到了mpich2

1. MPI Tutorial
2. MPI2 Tutorial
3. Tut範例集
4. MPI bcast範例

Assignment#1:

#include 
#include "mpi.h"

int main(int  argc, char *argv[])
    { int rank, size;
    MPI_Init( &argc, &argv );
    MPI_Comm_size( MPI_COMM_WORLD, &size );
    MPI_Comm_rank( MPI_COMM_WORLD, &rank );
    printf( "Hello world from process %d of %d\n", rank, size );
    MPI_Finalize();
    return 0; }

Makefile:

ALL: Hello

Hello: Hello.c
 mpicc -o helloworld helloworld.c

clean:
 /bin/rm -f helloworld *.o

主要是先要去瞭解一些API的用法:

1. MPI_Init:
2. MPI_Comm_rank:
3. MPI_Bcast:
4. MPI_Finalize:

#Monday, February 06, 2006 posted by samuel @ 11:46 PM 0 comments