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我想使用 MPIMPI_File_read_all读取input.txt包含二进制整数的文件0,1,2,...,1000。

在我的实现中，我使用从 10*10 数组MPI_Type_create_subarray中创建一个 5*5 子数组。mysub希望从文件中读取以下矩阵。

0       1       2       3       4
10      11      12      13      14
20      21      22      23      24
30      31      32      33      34
40      41      42      43      44

但是我的程序改为读取以下整数（也会导致程序最后阶段的分段错误）：

0       1       2       3       4
22002   -1984077600     22002   0       0
10      11      12      13      14
0       0       0       0       0
20      21      22      23      24

这是我的代码

#include<iostream>                                                                                                                                               
#include<mpi.h>                                                                                                                                                  
using namespace std;  

void read_subarray(const MPI_File &fh, int rank) {
    int bigsize = 10, subsize = 5;
    int **A = new int*[subsize];
    int *buf = new int[subsize*subsize];
    for (int i=0;i<subsize;i++) A[i] = &buf[subsize*i];

    int bigsizes[] = {bigsize, bigsize};
    int subsizes[] = {subsize, subsize};
    int offsets[] = {0, 0};

    MPI_Datatype mysub;
    MPI_Type_create_subarray(2, bigsizes, subsizes, offsets, MPI_ORDER_C, MPI_INT, &mysub);
    MPI_Type_commit(&mysub);

    MPI_Status status;
    int disp = 0;
    MPI_File_set_view(fh, disp, MPI_INT, mysub, "native", MPI_INFO_NULL);
    MPI_File_read_all(fh, &(A[0][0]), 1, mysub, &status);

    cout<<"array for "<<rank<<endl;
    for (int i=0;i<subsize; i++) {
        for (int j=0;j<subsize; j++) 
            cout<<A[i][j]<<"\t"; 
        cout<<endl;
    }


    MPI_Type_free(&mysub);
}

int main(int argc, char** argv)
{

    int rank, size;
    MPI_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &size);

    MPI_File fh;
    MPI_File_open(MPI_COMM_WORLD, "./input.txt", MPI_MODE_RDONLY, MPI_INFO_NULL, &fh);

    read_subarray(fh, rank);

    MPI_File_close(&fh);
    MPI_Finalize();
    return 0;
}
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