Question

所以我正在使用MPI开发一个项目，我正在尝试创建自己的结构。我遇到的问题是它似乎无法正常工作，因为我从未在工作人员中收到任何东西，所以我超时了。我尝试使用标准的MPI_INT，效果很好。但是，当我尝试实现自己的类型时，它并不喜欢它......这是我的代码：

#include <iostream>
#include <mpi.h>
#include "main.hpp"

int main(int argc, char *argv[]){
    //initialize MPI
    MPI_Init(&argc, &argv);

    message_to_worker message;
    //declare my new type
    MPI_Datatype MessageType;

    //declare the types the the structure will have
    MPI_Datatype type[1] = { MPI_INT };
    //the number of results for each type(int[50] will be 50 etc..)
    int blocklen[1] = {1};

    //this will store the displacement for each var in the structure
    MPI_Aint disp[1] = {0};
    MPI_Aint var1, var2;

    //number of vars
    int count = 1;

    //define the type
    MPI_Type_struct(count, blocklen, disp, type, &MessageType);
    MPI_Type_commit(&MessageType); 

    std::cout << "The displacement is " << disp[0] << std::endl;

    int rank;
    int world_size;

    //give me my current rank(node 1 reiceves 1 , node 2 etc... )
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &world_size);

    int counter = 1;
    message.N = 5;

    //IF MASTER
    if (rank == 0) {
        int result;

        //send messages to the workers
        while(counter<world_size){
            //send 1 message of type MessageType using my own structure(first parameter)
            result = MPI_Ssend(&message, 1, MessageType, counter, 123, MPI_COMM_WORLD);

            //make sure the mssage was sent correctly
            if (result == MPI_SUCCESS){
                std::cout << "I am master and the world size is : " << world_size << std::endl;
                std::cout << " I send a message to mky worker thread " << std::endl;
            }else{
                std::cout << "There was a problem with the sending for worker " << counter << std::endl;
            }
            counter++;
        }
    }
    //IF WORKER
    else if (rank > 0) {
        //the worker will wait until it receives a message
        int result = MPI_Recv(&message, 1, MessageType, 0, 0, MPI_COMM_WORLD,
                  MPI_STATUS_IGNORE);

        //make sure the message was RECEIVED correctly
        if (result == MPI_SUCCESS){
            std::cout << "Worker - Rank: " << rank <<" OK! and the value received through the message is " << message.N << std::endl;
        }
    }

    //shutdown MPI
    MPI_Finalize();
    return 0;

}

Answer 1

我的标签参数（最后一个参数）对于发件人和收件人来说是不同的。主人使用标签123，工作人员正在寻找标签0.他们都需要同步，因为他们需要建立通信渠道。这是修复（请注意第5个参数，标记如何更改）。

<强>之前：

MPI_Ssend(&message, 1, MessageType, counter, 123, MPI_COMM_WORLD);

MPI_Recv(&message, 1, MessageType, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);

<强>后

MPI_Ssend(&message, 1, MessageType, counter, 123, MPI_COMM_WORLD);

MPI_Recv(&message, 1, MessageType, 0, 123, MPI_COMM_WORLD, MPI_STATUS_IGNORE);

C ++ Open-MPI：自定义结构类型无法通过Ssend发送

1 个答案: