enp1s0/mpitf

MPI Template Functions

Introduction

mpitf is a tiny MPI template library.

• header file only
• at least C++11

Original functions

Get a rank and size within a node

• mpitf::get_rank_within_node(MPI_Comm)
• mpitf::get_size_within_node(MPI_Comm)

These functions distinguish nodes using their host name.

Namespace structure

mpitf
└─ error

Sample

#include <iostream>
#include <mpitf.hpp>

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

        int rank = mpitf::get_comm_rank(MPI_COMM_WORLD);
        int nprocs = mpitf::get_comm_size(MPI_COMM_WORLD);

        int local_rank = mpitf::get_rank_within_node(MPI_COMM_WORLD);
        int local_size = mpitf::get_size_within_node(MPI_COMM_WORLD);

        std::printf("%4d / %4d : local rank = %4d / %4d\n", rank, nprocs, local_rank, local_size);

        using data_t = int;
        data_t send = rank;
        data_t recv = 0;
        MPITF_HANDLE_ERROR(MPI_Allreduce(&send, &recv, 1, mpitf::get_data_type<data_t>(), MPI_SUM, MPI_COMM_WORLD));
        std::cout << "Allreduce sum = " << recv <<std::endl;

        MPI_Finalize();
}