mpi中c语言结构体怎么通信,C语言中的struct serialization和通过MPI传输

Jonathan Dur..

59

Jeremiah是对的 - MPI_Type_create_struct是去的地方.

重要的是要记住MPI是一个没有内置于该语言中的库; 所以它无法"看到"结构本身序列化的样子.因此,要发送复杂的数据类型,您必须明确定义其布局.在一种对序列化有本机支持的语言中,一组MPI包装器可以巧妙地利用它; 例如,mpi4py利用python的pickle来透明地发送复杂的数据类型; 但在C中,你必须卷起袖子自己动手.

对于您的结构,它看起来像这样:

#include

#include

#include

#include

typedef struct car_s {

int shifts;

int topSpeed;

} car;

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

const int tag = 13;

int size, rank;

MPI_Init(&argc, &argv);

MPI_Comm_size(MPI_COMM_WORLD, &size);

if (size < 2) {

fprintf(stderr,"Requires at least two processes.\n");

exit(-1);

}

/* create a type for struct car */

const int nitems=2;

int blocklengths[2] = {1,1};

MPI_Datatype types[2] = {MPI_INT, MPI_INT};

MPI_Datatype mpi_car_type;

MPI_Aint offsets[2];

offsets[0] = offsetof(car, shifts);

offsets[1] = offsetof(car, topSpeed);

MPI_Type_create_struct(nitems, blocklengths, offsets, types, &mpi_car_type);

MPI_Type_commit(&mpi_car_type);

MPI_Comm_rank(MPI_COMM_WORLD, &rank);

if (rank == 0) {

car send;

send.shifts = 4;

send.topSpeed = 100;

const int dest = 1;

MPI_Send(&send, 1, mpi_car_type, dest, tag, MPI_COMM_WORLD);

printf("Rank %d: sent structure car\n", rank);

}

if (rank == 1) {

MPI_Status status;

const int src=0;

car recv;

MPI_Recv(&recv, 1, mpi_car_type, src, tag, MPI_COMM_WORLD, &status);

printf("Rank %d: Received: shifts = %d topSpeed = %d\n", rank,

recv.shifts, recv.topSpeed);

}

MPI_Type_free(&mpi_car_type);

MPI_Finalize();

return 0;

}