mpi_lbm.c

格子Boltzmann方法 格子Boltzmann方法是为了保留格子气自动机方法的优点

/**********************************************************
 *  mpi_lbm.c                                             *
 *  mpicc -o mpi_lbm mpi_lbm.c mpi_D2Q9.c MyArrays.c -lm  *    
 **********************************************************/
#include "mpi.h"
#include <stdio.h>
#include "mpi_D2Q9.h"

int main(int argc, char *argv[])
{
    double wtime, ctime, wtime_max, ctime_sum;
    int namelen, myid, numprocs, i;
    char processor_name[MPI_MAX_PROCESSOR_NAME];

// STEP 1 (MPI Initialization)
    MPI_Init(&argc, &argv);
    MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
    MPI_Comm_rank(MPI_COMM_WORLD, &myid);
    MPI_Get_processor_name(processor_name, &namelen);

// STEP 2 (Data distribution --- periodic)
    if(myid == 0)
    {
        if(argc>1) ReadParaFile(argv[1]);
        else       ReadParaFile("bdy.lbm");
    }
    InitData(numprocs, myid);

// STEP 3 (Parallel dowork)
    MPI_Barrier(MPI_COMM_WORLD);
    ctime = CPU_time();
    wtime = MPI_Wtime();

    for(i=0; i<5000; i++)
        evolution(numprocs, myid);

// STEP 4 (Collect the results)
    ctime = CPU_time() - ctime;
    wtime = MPI_Wtime() - wtime;

    printf("Process %d of %d on %s, tc=%f, tw=%f\n",
            myid, numprocs, processor_name, ctime, wtime);
    fflush(stdout);

    CollectData(numprocs, myid);
    if(myid==0)
        SaveFile();

// STEP 5 (Display the results)
    MPI_Reduce(&ctime, &ctime_sum, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);
    MPI_Reduce(&wtime, &wtime_max, 1, MPI_DOUBLE, MPI_MAX, 0, MPI_COMM_WORLD);

    if(myid==0)
    {
        printf("Sum_CPU_time = %f, Max_WALL_time = %f\n", ctime_sum, wtime_max);
        printf("Sum_CPU_time/Max_WALL_time = %f\n", ctime_sum/wtime_max);
    }

// STEP 6 (Terminates MPI execution environment)
    Finish();
    MPI_Finalize();
    return 0;
}