std::vector 个中的 MPI_Send/Recv 个不匹配

Question

我不明白为什么这段代码在接收到的向量上打印 0 而不是 1，我做错了什么吗？
通信正常，但它只打印五个零而不是四个零和一个一。

int main(int arg, char** argvs) {
    int rank, numOfProcess;
    MPI_Init(&arg, &argvs);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &numOfProcess);
    MPI_Status status;
    if (rank == 0) {
        vector<int> prova(5);
        prova.push_back(1);
        MPI_Send(prova.data(), 5, MPI_INT, 1, 0, MPI_COMM_WORLD);
    }
    if (rank == 1) {
        vector<int> rec(5);
        MPI_Recv(rec.data(), 5, MPI_INT, 0, 0, MPI_COMM_WORLD, &status);
        cout << rec.back() << endl;
    }
    MPI_Finalize();
    return 0;
}

Answer 1

您的 push_back 将向量的长度增加一。因此，您正在通信两个小向量。

#include <mpi.h>
#include <iostream>
#include <vector>
using namespace std;
int main(int arg, char** argvs) {
    int rank, numOfProcess;
    MPI_Init(&arg, &argvs);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &numOfProcess);
    MPI_Status status;
    if (rank == 0) {
        std::vector<int> prova(5);
        prova.push_back(1);
        MPI_Send(prova.data(), 6, MPI_INT, 1, 0, MPI_COMM_WORLD);
    }
    if (rank == 1) {
        std::vector<int> rec(6);
        MPI_Recv(rec.data(), 6, MPI_INT, 0, 0, MPI_COMM_WORLD, &status);
        cout << rec.back() << endl;
    }
    MPI_Finalize();
    return 0;
}

std::vector 个中的 MPI_Send/Recv 个不匹配

MPI_Send/Recv of std::vector not matching

c++

parallel-processing

mpi