managerworker.c

简单的并行计算示例

#include "mpi.h"
#include <stdio.h>
#define SIZE 500
#define MIN(x,y) ((x) < (y) ? x : y)

void manager_code (int numprocs) ;

void worker_code(void) ;

int main(int argc,char *argv[])
{
	int numprocs,myrank ;
	int namelen ;
	char processor_name[MPI_MAX_PROCESSOR_NAME] ;
	char greeting[MPI_MAX_PROCESSOR_NAME+80] ;
	MPI_Init( &argc , &argv ) ;
	MPI_Comm_size( MPI_COMM_WORLD, &numprocs ) ;
	MPI_Comm_rank( MPI_COMM_WORLD, &myrank ) ;
	MPI_Get_processor_name(processor_name,&namelen) ;
	sprintf(greeting,"process %d of %d on %s",myrank,numprocs,processor_name) ;
	if( myrank == 0 )
	{
		manager_code( numprocs ) ;
	}
	else
		worker_code() ;
	MPI_Finalize() ;
	return 0 ;
}


void manager_code (int numprocs)
{
	double a[SIZE][SIZE],c[SIZE];
	int i,j,sender,row,numsent =0;
	double dotp;
	MPI_Status status;
	for (i=0; i<SIZE ;i++)
		for(j=0; j<SIZE; j++)
	        a[i][j]=(double) j;

	for (i=1;i<MIN(numprocs ,SIZE);i++)
	{
        	MPI_Send(a[i-1],SIZE,MPI_DOUBLE, i, i,MPI_COMM_WORLD);
		printf("Manager give a work to worker &d\n", i ) ; 
        	numsent++;
	}
	for (i=0;i<SIZE;i++)
	{
     		MPI_Recv(&dotp,1,MPI_DOUBLE,MPI_ANY_SOURCE,MPI_ANY_TAG,
			MPI_COMM_WORLD,&status);
		sender=status.MPI_SOURCE;
		row=status.MPI_TAG -1;
		c[row]=dotp;
        	if (numsent<SIZE)
		{
			printf("worker %d has finished one work!\n", sender) ;
			printf("Manager give work %d to him\n" ,numsent) ;
			MPI_Send(a[numsent],SIZE,MPI_DOUBLE,sender,numsent+1,MPI_COMM_WORLD);
			numsent++;	
		}
    		else 
   		{
			printf("worker %d's work is done!\n", sender) ;
			MPI_Send(MPI_BOTTOM,0,MPI_DOUBLE,sender,0,MPI_COMM_WORLD);
		}
	}
}



void worker_code(void)
{
	double b[SIZE], c[SIZE] ;
	int i ,row , myrank ;
	double dotp ;
	MPI_Status status ;

	for( i = 0 ; i < SIZE; i ++ )
		b[i] = 1.0 ;
	
	MPI_Comm_rank( MPI_COMM_WORLD, &myrank ) ;
	if( myrank <= SIZE )
	{
		MPI_Recv( c, SIZE, MPI_DOUBLE,0,MPI_ANY_TAG, MPI_COMM_WORLD,
			&status ) ;
		while( status.MPI_TAG > 0 )
		{
			row = status.MPI_TAG -1 ;
			dotp = 0.0 ;
			for ( i = 0 ; i < SIZE ; i++ )
				dotp += c[i] * b[i] ;
			MPI_Send(&dotp, 1, MPI_DOUBLE, 0, row + 1, MPI_COMM_WORLD ) ;
			MPI_Recv(c , SIZE, MPI_DOUBLE, 0, MPI_ANY_TAG, 					MPI_COMM_WORLD,&status ) ;
		}
	}
}