Question

我不明白为什么这个代码在收到的矢量上打印0而不是1，我做错了什么？通信正在工作，但它只打印五个零而不是四个零和一个。

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

你的push_back正在将向量的长度增加一。因此，您正在传达一个两个小向量。

#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;
}

MPI_Send / recv of std :: vector不匹配

1 个答案: