我使用MPI在C中编写了一个程序,其中struct变量将以环形方式发送给进程,并根据从该变量接收的值分配该特定进程的工作。
问题是我需要知道如何在MPI_Send()
函数中发送一个struct变量,因为它在运行时给出了INVALID DATATYPE,请考虑以下示例
struct info{
int ne, n, u, v, process, min, strip, mincost, b;
} stat;
MPI_Send(&stat,sizeof(stat),sizeof(struct info),1,2,MPI_COMM_WORLD);
答案 0 :(得分:5)
在发送结构之前,您必须执行一些操作。 我为您的示例编写了代码,但为了更好地理解您应该阅读一些文档。 无论如何,这里有一些提示:
struct point{ int x; double y; };
这里是代码:
struct info{
int ne, n, u, v, process,min,strip,mincost,b;
}stat;
int main(...){
/*MPI INIT*/
struct info _info,
int count; //Says how many kinds of data your structure has
count = 1; //1, 'cause you just have int
// Says the type of every block
MPI_Datatype array_of_types[count];
// You just have int
array_of_types[0] = MPI_INT;
// Says how many elements for block
int array_of_blocklengths[count];
// You have 8 int
array_of_blocklengths[0] = {8};
/* Says where every block starts in memory, counting from the beginning of the struct. */
MPI_Aint array_of_displaysments[coun];
MPI_Aint address1, address2;
MPI_Get_address(&_info,&address1);
MPI_Get_address(&_info.ne,&address2);
array_of_displaysments[0] = address2 - address1;
/*Create MPI Datatype and commit*/
MPI_Datatype stat_type;
MPI_Type_create_struct(count, array_of_blocklengths, array_of_displaysments, array_of_types, &stat_type);
MPI_Type_commit(&stat_type);
// Now we are ready to send
MPI_Send(&_info, 1, stat_type, dest, tag, comm),
/* . . . */
// Free datatype
MPI_Type_free(&stat_type);
// MPI finalization
MPI_Finalize();
}
答案 1 :(得分:-1)
试试这个
MPI_Send(&stat,sizeof(struct info),MPI_CHAR,1,2,MPI_COMM_WORLD);
MPI_Recv(&data,sizeof(struct info), MPI_CHAR, 0, DEFAULT_TAG, MPI_COMM_WORLD, &status);
stat = (struct info *) data;