ecearth3/sources/lpjg/framework/parallel.cpp

///////////////////////////////////////////////////////////////////////////////////////
/// \file parallel.cpp
/// \brief Functionality for parallel computation
///
/// \author Joe Siltberg
/// $Date: 2013-10-10 10:20:33 +0200 (Thu, 10 Oct 2013) $
///
///////////////////////////////////////////////////////////////////////////////////////

// mpi.h needs to be the first include (or specifically, before stdio.h),
// due to a bug in the MPI-2 standard (both stdio.h and the C++ MPI API
// defines SEEK_SET, SEEK_CUR and SEEK_SET(!))
#ifdef HAVE_MPI
#include <mpi.h>
#endif

#include "config.h"
#include "parallel.h"
#include "shell.h"
#include <memory>
#include <string>


namespace GuessParallel {

bool parallel = false;

#ifdef HAVE_MPI

/// A class whose only purpose is to terminate the MPI library when deleted
class FinalizeCaller {
public:
	~FinalizeCaller() {
		MPI_Finalize();
	}
};

/// The auto pointer will delete the object some time after main() is finished
std::auto_ptr<FinalizeCaller> destructor;

#endif

void init(int& argc, char**& argv) {

#ifdef HAVE_MPI

	// Only initialize MPI is the command line options explicitly
	// asks for a parallel run (with the -parallel option).
	// In most cases it wouldn't hurt to initialize MPI even if
	// it's not used, but apparently some implementations start
	// by going to the users home directory if the program isn't
	// launched by an mpiexec/mpirun launcher.

	// Unfortunately, since MPI initialization must be done before
	// we parse our options with CommandLineArguments, we need to
	// look for the -parallel option here by ourselves.
	// The file-global variable parallel is initiated = false;
	for (int i = 0; i < argc; ++i) {
		if (std::string(argv[i]) == "-parallel") {
			parallel = true;
			break;
		}
	}

	// ecev3 - Spinup?
	bool spinup = false;
	for (int i = 0; i < argc; ++i) {
		if (std::string(argv[i]) == "-islpjgspinup") {
			spinup = true;
			break;
		}
	}

	if (parallel && (spinup || ECEARTHWITHCRUNCEP)) {
		// We won't use OASIS-MCT in this case, so we must initialise MPI.
		dprintf("Parallel spinup of LPJ_GUESS - calling MPI_Init\n");
		int ierr = MPI_Init(&argc, &argv);
		dprintf("LPJ_GUESS returned from calling MPI_Init with code %i\n",ierr);

		// Make sure the MPI_Finalize function is called at program termination
		destructor = std::auto_ptr<FinalizeCaller>(new FinalizeCaller());
	}
#endif
}

int get_rank() {
#ifdef HAVE_MPI
	int rank;
	int ierr = MPI_Comm_rank(MPI_COMM_WORLD, &rank);
	return rank;
#else
	return 0;
#endif
}

int get_rank_specific(int lc) {
#ifdef HAVE_MPI
	int rank;
	#ifdef OPEN_MPI
	MPI_Comm comm = MPI_Comm_f2c((MPI_Fint) lc);
	#else
	int comm = lc;
	#endif
	//dprintf("LPJ_GUESS - get_rank_specific() with communicator %i\n",lc);
	int ierr = MPI_Comm_rank(comm, &rank);
	//dprintf("LPJ_GUESS - get_rank_specific() returned error: %i and rank %i\n",ierr,rank);
	return rank;
#else
	return 0;
#endif
}


int get_global_rank() {
#ifdef HAVE_MPI
        int rank;
        MPI_Comm_rank(MPI_COMM_WORLD, &rank);
        return rank;
#else
        return 0;
#endif
}


int get_num_processes() {
#ifdef HAVE_MPI
	if (parallel) {
		int size;
		MPI_Comm_size(MPI_COMM_WORLD, &size);
		return size;
	}else
		return 1;	
#else
	return 1;
#endif
}

int get_num_local_processes(int lc) {
#ifdef HAVE_MPI
	int size;
	#ifdef OPEN_MPI
	MPI_Comm comm = MPI_Comm_f2c((MPI_Fint) lc);
	#else
	int comm = lc;
	#endif
	MPI_Comm_size(comm, &size);
	return size;
#else
	return 1;
#endif
}


int get_num_global_processes() {
#ifdef HAVE_MPI
	int size;
	MPI_Comm_size(MPI_COMM_WORLD, &size);
	return size;
#else
	return 1;
#endif
}

}