这是我计算素数的代码,我只想在这些过程中使用集体通信。但是,当我使用'MPI_Scatter'和'MPI_Gather'而不是MPI_Recv和MPI_Isend更改我的代码时,出现错误。我应该改变什么?Parellel编程:我如何申请'MPI_Gather'或'MPI_Scatter'而不是'MPI_Isend'和'MPI_Recv'
这是我的原代码:
MPI_Request req;
MPI_Status status;
MPI_Init(&argc,&argv);
MPI_Comm_size(MPI_COMM_WORLD, &p);
MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
if(my_rank == 0){
printf("Input(50-1000) : ");
fflush(stdout);
scanf("%d",&w);
for(i=0; i<w; i++) data[i] = i+1;
}
MPI_Bcast(&w, 1, MPI_INT,0,MPI_COMM_WORLD);
MPI_Bcast(data, w, MPI_INT,0,MPI_COMM_WORLD);
if(my_rank != 0){
x = w/(p-1);
low = (my_rank-1)*x;
high = low+x-1;
for(num = data[low]; num <= data[high];num++){
result = 0;
t=1;
while(num>=t){
if(num%t==0)
result = result +1;
t += 1;
}
if(result==2) i += 1;
}
MPI_Isend(&i,1,MPI_INT,0,0,MPI_COMM_WORLD,&req);
}
if(my_rank == 0){
int j = 0;
for(j = 1; j < p; j++){
MPI_Recv(&i,1,MPI_DOUBLE,MPI_ANY_SOURCE,0,MPI_COMM_WORLD,&status);
printf("Process %d : There are %d prime numbers\n",status.MPI_SOURCE,i);
}
}
MPI_Finalize();
}
,输出是:
Input(50-1000) : 50
Process 1 : There are 5 prime numbers
Process 2 : There are 4 prime numbers
Process 3 : There are 2 prime numbers
Process 4 : There are 4 prime numbers
这里是我改变了我的代码部分:
if(my_rank != 0){
x = w/(p-1);
low = (my_rank-1)*x;
high = low+x-1;
for(num = data_send[low]; num <= data[high];num++){
result = 0;
t=1;
while(num>=t){
if(num%t==0)
result = result +1;
t += 1;
}
if(result==2) i += 1;
}
MPI_Scatter(data_send,1,MPI_INT,data_recv,1,MPI_INT,0,MPI_COMM_WORLD);
}
什么错误没有你得到 – cowbert
它只显示'输入(50-1000):'输入问题,似乎程序继续运行而不提供结果 – Lumby
请注意您发送'MPI_INT',但收到'MPI_DOUBLE'。而且你也不会'MPI_Wait()''MPI_Isend()'返回的请求' –