Question

我想用MPI_Neighbor_alltoall在网格中的节点之间交换weatherdata结构。我的程序编译并运行，但交换的数据不正确。

我的weatherdata结构

worker()

我的创建购物车代码段

typedef struct s_weatherdata{
        // coordinates
        float lon;
        float lat;
        // main
        int pressure;
        int humidity;
        int temp;
        // wind
        int speed;
        int deg;
}weatherdata;

创建MPI weatherdata struct

    // Create Dimensions
    MPI_Dims_create(size, ndims, dims);

    // Create Cartesian
    MPI_Cart_create(mycomm, ndims, dims, periods, 1, &cart_comm);

    // Get the name of the processor
    char processor_name[MPI_MAX_PROCESSOR_NAME];
    int len;
    MPI_Get_processor_name(processor_name, &len);

    // Get coordinates
    MPI_Cart_coords(cart_comm, rank, ndims, coord);

我所需要的只是＆＃39;速度＆＃39;和＆＃39; deg＆＃39;来自weatherdata结构。我的输出看起来像：

输出

    // create a type for weatherdata
    const int nitems = 7;
    int blocklengths[7] = {1,1,1,1,1,1,1};
    MPI_Datatype types[7] = {MPI_FLOAT, MPI_FLOAT, MPI_INT, MPI_INT, MPI_INT, MPI_INT, MPI_INT};
    MPI_Datatype tmp_mpi_weatherdata, mpi_weatherdata;
    MPI_Aint offsets[7];
    MPI_Aint lb, extent;

    offsets[0] = offsetof(weatherdata, lon);
    offsets[1] = offsetof(weatherdata, lat);
    offsets[2] = offsetof(weatherdata, pressure);
    offsets[3] = offsetof(weatherdata, humidity);
    offsets[4] = offsetof(weatherdata, temp);
    offsets[5] = offsetof(weatherdata, speed);
    offsets[6] = offsetof(weatherdata, deg);

    MPI_Type_create_struct(nitems, blocklengths, offsets, types, &tmp_mpi_weatherdata);
    MPI_Type_get_extent(tmp_mpi_weatherdata, &lb, &extent);
    MPI_Type_create_resized(tmp_mpi_weatherdata, lb, extent, &mpi_weatherdata);
    MPI_Type_commit(&mpi_weatherdata);



    weatherdata **recvdata = malloc(4*sizeof(weatherdata *));

    weatherdata *data0 = malloc(4*(sizeof(weatherdata)));
    weatherdata *data1 = data0+sizeof(weatherdata);
    weatherdata *data2 = data1+sizeof(weatherdata);
    weatherdata *data3 = data2+sizeof(weatherdata);

    recvdata[0]=data0;
    recvdata[1]=data1;
    recvdata[2]=data2;
    recvdata[3]=data3;


    MPI_Neighbor_alltoall(my_data , 1, mpi_weatherdata, data0, 1, mpi_weatherdata, cart_comm);

    printf("data0: %i %i\n", recvdata[0]->speed, recvdata[0]->deg);
    printf("data1: %i %i\n", recvdata[1]->speed, recvdata[1]->deg);
    printf("data2: %i %i\n", recvdata[2]->speed, recvdata[2]->deg);
    printf("data3: %i %i\n", recvdata[3]->speed, recvdata[3]->deg);

Answer 1

如果您想使用MPI_Neighbor_alltoall，则代替

weatherdata **recvdata = malloc(4*sizeof(weatherdata *));

你应该

weatherdata recvdata[4];

如果您需要使用此类间接，则应调查MPI_Neighbor_alltoallw。

如果您仍需要一些帮助，请发布mcve以便获得帮助。

MPI Cartesian拓扑：MPI_Neighbor_alltoall发送错误的数据

1 个答案: