c: test split MPI_Comm with gbpSID

SConstruct

import os

env = Environment(env=os.environ)

env.Replace(CC = "mpicc")
env.AppendUnique(CFLAGS = ["-std=gnu99"])

libs = {}
libs["gbpCode"] = {"I" : "~/3rd_party/gbpCode/myInclude",
    "L" : "~/3rd_party/gbpCode/myLib/mpi",
    "l" : "gbpLib",
}

for lib in libs.itervalues():
    env.AppendUnique(CPPPATH = os.path.expanduser(lib["I"]))
    env.AppendUnique(LIBPATH = os.path.expanduser(lib["L"]))
    env.AppendUnique(LIBS = os.path.expanduser(lib["l"]))

sources = ["split.c"]

env.Program("split", sources)

split.c

#define _MAIN
#include <stdio.h>
#include <stdlib.h>
#include <mpi.h>
#include <gbpLib.h>

int main(int argc, char *argv[])
{
  // Init MPI
  MPI_Init(&argc, &argv);

  // Copy the world communicator
  MPI_Comm world;
  MPI_Comm_dup(MPI_COMM_WORLD, &world);

  // Get this rank's info on world
  int world_rank, world_size;
  MPI_Comm_rank(world, &world_rank);
  MPI_Comm_size(world, &world_size);

  fprintf(stderr, "I am world rank %d(/%d)\n", world_rank, world_size);

  // Create a new split communicator
  // All odd odd have color 0 and all evens have color 1
  int my_color = (world_rank % 2) ? 0 : 1;
  MPI_Comm split_comm;
  MPI_Comm_split(world, my_color, world_rank, &split_comm);
  int split_rank, split_size;
  MPI_Comm_rank(split_comm, &split_rank);
  MPI_Comm_size(split_comm, &split_size);

  fprintf(stderr, "I am world rank %d(/%d), have color %d and split_comm rank %d(/%d)\n",
      world_rank, world_size, my_color, split_rank, split_size);

  // Call SID_init
  SID_init(&argc, &argv, NULL, &split_comm);
  SID_log_set_fp(stderr);
  SID_log("I am world rank %d(/%d), have color %d and SID rank %d(/%d)\n",
      SID_LOG_COMMENT|SID_LOG_ALLRANKS, world_rank, world_size, my_color,
      SID.My_rank, SID.n_proc);

  // Free the comms we made
  // N.B. We don't need to free split_comm as this was done by SID_init
  MPI_Comm_free(&world);

  // Call SID_Finalize (which contains an MPI_Finalize call)
  SID_exit(EXIT_SUCCESS);
}