并行计算实验2--多结点运行程序

并行计算实验2

2021.11.24

创建结点

docker run --rm --name=node1 --network=mpi-net -v /root/program:/root/program -itd  mpi-centos

查看结点

进入结点

docker exec -it e21c327ef219 /bin/bash

由于我们的共享地址是 ：/root/program,所以将server文件创建在这里，编译后的文件也放在这里

创建servers文件

#当前目录是/root/program
vi servcers 
node1:3
node2:3
node3:3

编译cpi文件到此

mpicc /root/mpich-3.2/examples/cpi.c -o /root/program/cpi

当前的文件:ls

执行编译

mpirun -n 9 -f ./servers ./cpi

三．MPI程序演示

新建pi.c

#include <stdio.h>
#include <stdlib.h> 
#include <math.h> 
#include <time.h> 
#include <mpi.h> 

void read_num(long long int *num_point,int my_rank,MPI_Comm comm); 
void compute_pi(long long int num_point,long long int* num_in_cycle,
                long long int* local_num_point,int comm_sz,long long int *total_num_in_cycle,MPI_Comm comm,int my_rank); 

int main(int argc,char** argv){ 
    long long int num_in_cycle,num_point,total_num_in_cycle,
    local_num_point; 
    int my_rank,comm_sz; 
    double begin,end; 
    MPI_Comm comm; MPI_Init(NULL,NULL);//初始化 
    comm=MPI_COMM_WORLD; 
    MPI_Comm_size(comm,&comm_sz);//得到进程总数 MPI_Comm_rank(comm,&my_rank);//得到进程编号 

    read_num(&num_point,my_rank,comm);//读取输入数据begin=MPI_Wtime();
    compute_pi(num_point,&num_in_cycle,&local_num_point,comm_sz,&total_num_in_cycle,comm,my_rank); 
    end=MPI_Wtime(); 
    if(my_rank==0){ printf("Elapsing time: %fs\n",end-begin); } 
    MPI_Finalize(); 
    return 0; 
} 

void read_num(long long int* num_point,int my_rank,MPI_Comm comm){ 
    if(my_rank==0){ 
        printf("please input num in sqaure \n"); scanf("%lld",num_point); } 
    MPI_Bcast(num_point,1,MPI_LONG_LONG,0,comm); 
} 

void compute_pi(long long int num_point,long long int* num_in_cycle,long long int* local_num_point,int comm_sz,long long int *total_num_in_cycle,MPI_Comm comm,int my_rank){
    *num_in_cycle=0; 
    *local_num_point=num_point/comm_sz; 
    double x,y,distance_squared; 
    srand(time(NULL)); 
    for(long long int i=0;i< *local_num_point;i++){ 
        x=(double)rand()/(double)RAND_MAX; 
        x=x*2-1; 
        y=(double)rand()/(double)RAND_MAX; 
        y=y*2-1; 
        distance_squared=x*x+y*y; 
        if(distance_squared<=1) 
            *num_in_cycle=*num_in_cycle+1; 
    } MPI_Reduce(num_in_cycle,total_num_in_cycle,1,MPI_LONG_LONG,MPI_SUM,0,comm); 
    if(my_rank==0){ 
        double pi=(double)*total_num_in_cycle/(double)num_point*4; printf("the estimate value of pi is %lf\n",pi); 
    } 
}

编译

mpicc pi.c -std=c99 -o pi  #不写后面会报错

运行

mpirun -n 1 ./pi