MPI并行程序设计之平行Rank

#include<stdio.h>
#include<stdlib.h>
#include<malloc.h>
#include<math.h>
#include"mpi.h"
struct parallel{
int nnum;
int rrank;
};
int main(int argc, char** argv)
{
int rank,size,*sbuf,rbuf[10],i;
int* rrbuf;
int num;
MPI_Init(&argc,&argv);
MPI_Comm_size(MPI_COMM_WORLD,&size);
MPI_Comm_rank(MPI_COMM_WORLD,&rank);
if(rank==0)
{

sbuf=(int*)malloc(sizeof(int)*size);
rrbuf=(int*)malloc(sizeof(int)*2*size);
for(i=0;i<size;i++)
sbuf[i]=rand()%10;
//struct parallel   pa[size];
}
MPI_Scatter(sbuf,1,MPI_INT,rbuf,1,MPI_INT,0,MPI_COMM_WORLD);
rbuf[1]=rank;
MPI_Gather(rbuf,2,MPI_INT,rrbuf,2,MPI_INT,0,MPI_COMM_WORLD);
if(rank==0)
{
struct parallel min;
struct parallel pa[size];
printf("Before the sort:\n");
int j;
int t;
printf("The num is: ");
for(i=0;i<2*size;i++)
{
if(i%2==0)
printf("%d ",rrbuf[i]);
}
printf("\n");
printf("The rank is ");
for(i=0;i<2*size;i++)
{
if(i%2!=0)
printf(" %d",rrbuf[i]);
}
printf("\n");

for(i=0;i<2*size;i++)
{
j=i/2;
if(i%2==0)
{
pa[j].nnum=rrbuf[i];
pa[j].rrank=rrbuf[i+1];
}
}
//---------------------sort----------------------------
for(i=0;i<size-1;i++)
{
for(j=i+1;j<size;j++)
{
if(pa[i].nnum>pa[j].nnum)
{
min=pa[i];
pa[i]=pa[j];
pa[j]=min;
}
}
}
printf("After sort:\n");
printf("The num is: ");
for(i=0;i<size;i++)
printf("%d ",pa[i].nnum);
printf("\n");
printf("The rank is: ");
for(i=0;i<size;i++)
printf("%d ",pa[i].rrank);
printf("\n");
}
//  printf("\n");
MPI_Finalize();
return 0;
}