MPI 检查通讯器是否 MPI_COMM_WORLD

Question

我需要检查 MPI 通信器是否 MPI_COMM_WORLD comm。这意味着所有处理器都在这个通信器中。

我试过了

int isCommWolrd(MPI_Comm comm) {
    int size_comm = 0;
    int size_comm_world = 0;
    MPI_Comm_size(comm, &size_comm);
    MPI_Comm_size(MPI_COMM_WORLD, &size_comm_world);
    return (size_comm == size_comm_world);
}

只检查通信器的尺寸是否足够。会不会出现阴性的假阳性？

Answer 1

使用MPI_Comm_compare()并检查结果是MPI_IDENT

int MPI_Comm_compare(MPI_Comm comm1, MPI_Comm comm2, int *result)
MPI_IDENT results if and only if comm1 and comm2 are handles for the same object (identical groups and same contexts). MPI_CONGRUENT results if the underlying groups are identical in constituents and rank order; these communicators differ only by context. MPI_SIMILAR results of the group members of both communicators are the same but the rank order differs. MPI_UNEQUAL results otherwise.

你的方法会导致误报。例如，如果您 MPI_Comm_dup(MPI_COMM_WORLD, &comm)，那么生成的 comm 与 MPI_COMM_WORLD 具有相同的大小，但它是不同的通信器。

MPI 检查通讯器是否 MPI_COMM_WORLD

MPI Check if communicator is MPI_COMM_WORLD

c

mpi

communicator