程序在MPI_Bcast之后挂起

Question

我是MPI的新手。我需要在2D拓扑（网格）中制作矩阵乘法程序。第一矩阵（A）沿x坐标分布，第二矩阵（B）沿y坐标分布。每个过程都会计算一个子矩阵。我使用MPI_Bcast在维度中发送子矩阵，但在该程序之后不会继续。我做错了什么？

这是代码。

#include<stdio.h>
#include<stdlib.h>
#include<mpi/mpi.h>

#define NUM_DIMS 2

#define N 81

#define A(i, j) A[N*(i)+(j)]
#define B(i, j) B[N*(i)+(j)]
#define C(i, j) C[N*(i)+(j)]
#define AA(i, j) AA[k *(i)+(j)]   //
#define BB(i, j) BB[k*(i)+(j)]
#define CC(i, j) CC[k*(i)+(j)]

int main(int argc, char **argv) {
    MPI_Init(&argc, &argv);

    int threadCount;
    int threadRank;
    MPI_Comm_size(MPI_COMM_WORLD, &threadCount);

    int dims[NUM_DIMS] = {0};

    //Создаем решетку
    int periods[2] = {0, 0};

    MPI_Comm comm_2D;
    MPI_Comm comm_1D[2];

    MPI_Dims_create(threadCount, NUM_DIMS, dims); 
    MPI_Cart_create(MPI_COMM_WORLD, 2, dims, periods, 0, &comm_2D);
    MPI_Comm_rank(comm_2D, &threadRank);

    int k = N/dims[1];

    double *A = (double*)calloc(N*N, sizeof(double));
    double *B = (double*)calloc(N*N, sizeof(double));
    double *C = (double*)calloc(N*N, sizeof(double));

    double startTime = MPI_Wtime();

    int subdims[2];
    subdims[0] = 0;
    subdims[1] = 1;
    MPI_Cart_sub(comm_2D, subdims, &comm_1D[0]); 
    subdims[0] = 1;
    subdims[1] = 0;
    MPI_Cart_sub(comm_2D, subdims, &comm_1D[1]);


    MPI_Datatype column, matrix;
    MPI_Type_vector(N, N / k, N, MPI_DOUBLE, &column);
    MPI_Type_create_resized(column, 0, N / k * sizeof(double), &column);
    MPI_Type_commit(&column);



    double *AA, *BB, *CC;
    AA = (double*)calloc(N * k, sizeof(double));
    BB = (double*)calloc(N * k, sizeof(double));
    CC = (double*)calloc(k * k , sizeof(double));

    int threadCoords[2];
    MPI_Comm_rank(comm_2D, &threadRank);
    MPI_Cart_coords(comm_2D, threadRank, NUM_DIMS, threadCoords);


    if (threadCoords[0] == 0) {
        for (int i = 0; i < N; ++i) {
            for (int j = 0; j < N; ++j) {
                A(i, j) = 1;
                B(i, j) = 1;
            }
        }
    }

    if (threadCoords[1] == 0) {
        MPI_Scatter(A, N * k, MPI_DOUBLE, AA, N * k, MPI_DOUBLE, 0, comm_1D[0]);
    }


    if (threadCoords[0] == 0) {
        int offset[3] = {0, 1, 2}; 
        int send[3] = {1, 1, 1}; 
        MPI_Scatterv(B, send, offset, column, BB, N * k , MPI_DOUBLE, 0, comm_1D[1]);
    }


    int r = MPI_Bcast(AA, k*N, MPI_DOUBLE, 0, comm_1D[1]);
    fprintf(stderr, "r = %d\n", r);
    int p = MPI_Bcast(BB, k*N, MPI_DOUBLE, 0, comm_1D[0]);
    fprintf(stderr, "p = %d\n", p);

    /*...*/
}