在C++中通过MPI_Iscatter()实现2D矩阵的分配

#include <mpi.h>

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

int rows = 4; // 矩阵的行数
int cols = 4; // 矩阵的列数
int num_procs; // 进程数量

MPI_Comm_size(MPI_COMM_WORLD, &num_procs);

int** matrix = new int*[rows];
for (int i = 0; i < rows; i++) {
    matrix[i] = new int[cols];
    for (int j = 0; j < cols; j++) {
        matrix[i][j] = i * cols + j;
    }
}

int* recv_buffer = new int[cols];

MPI_Iscatter(matrix[0], cols, MPI_INT, recv_buffer, cols, MPI_INT, 0, MPI_COMM_WORLD);

MPI_Request request;
MPI_Status status;

MPI_Isend(matrix[0], rows * cols, MPI_INT, 0, 0, MPI_COMM_WORLD, &request);
MPI_Wait(&request, &status);

for (int i = 0; i < cols; i++) {
    cout << recv_buffer[i] << " ";
}
cout << endl;

delete[] recv_buffer;

for (int i = 0; i < rows; i++) {
    delete[] matrix[i];
}
delete[] matrix;

MPI_Finalize();