impl. C++ template MPI Library

[t-hishinuma]

in monolish::mpi

• MPI_Allgatherv();
• MPI_Alloc_mem();
• MPI_Allreduce();
• MPI_Alltoall();
• MPI_Barrier();
• MPI_Comm_rank();
• MPI_Comm_size();
• MPI_Finalize();
• MPI_Get_count();
• MPI_Init();
• MPI_Initialized();
• MPI_recv();
• MPI_send();
• MPI_Irecv();
• MPI_Isend();
• MPI_Scatterv();
• MPI_Waitall();
• MPI_Bcast()
• MPI_Gather()
• MPI_Scatter()
• MPI_Allgather();

[t-hishinuma]

interface idea

test_dot(...){
  monolish::mpi::comm &comm = monolish::mpi::get_instance(); 

  ....

  return comm.Allreduce<double>(ans); 
}

int main(argc, argv){
  monolish::mpi::comm comm;  // singleton
  //or comm(external_comm);
  comm.Init(argc, argv); 

....

  ans = test_dot(x, y); //dont need comm

....

  comm.Finalize();
}

The comm class should be a singleton.
In monolish, only one comm is created per process.
There is not need to pass comm to functions.

[t-hishinuma]

class interface idea

class monolish::mpi::comm{
private: 
  MPI_COMM COMM;
  comm() = default;

  ~comm() {}; 
  

public:
  comm(const comm &) = delete;
  comm &operator=(const comm &) = delete;
  comm(comm &&) = delete;
  comm &operator=(comm &&) = delete;

  static comm &get_instance() {
    static comm instance;
    return comm;
  }

  void Init(.....);
  void Finalize();

  double Allreduce(double val);
  float Allreduce(float val);
  ....

[t-hishinuma]

MPI program need:

• #include "monolish_mpi.hpp"
• link monolish_*_mpi.so

[t-hishinuma]

Remove "request" from "waitall" and wait for all communications at once.