/* StarPU --- Runtime system for heterogeneous multicore architectures.
 *
 * Copyright (C) 2009, 2010, 2014-2015  Université de Bordeaux
 * Copyright (C) 2010, 2011, 2012, 2013, 2015, 2016  CNRS
 *
 * StarPU is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * StarPU is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * See the GNU Lesser General Public License in COPYING.LGPL for more details.
 */

#include <starpu_mpi.h>
#include "helper.h"

#ifdef STARPU_QUICK_CHECK
#  define NITER	16
#else
#  define NITER	2048
#endif

#define SIZE	16

float *tab;
starpu_data_handle_t tab_handle;

int main(int argc, char **argv)
{
	int ret, rank, size;

	MPI_Init(&argc, &argv);
	starpu_mpi_comm_rank(MPI_COMM_WORLD, &rank);
	starpu_mpi_comm_size(MPI_COMM_WORLD, &size);

	ret = starpu_init(NULL);
	STARPU_CHECK_RETURN_VALUE(ret, "starpu_init");
	ret = starpu_mpi_init(NULL, NULL, 0);
	STARPU_CHECK_RETURN_VALUE(ret, "starpu_mpi_init");

	if (size%2 != 0)
	{
		if (rank == 0)
			FPRINTF(stderr, "We need a even number of processes.\n");

		starpu_mpi_shutdown();
		starpu_shutdown();
		MPI_Finalize();
		return STARPU_TEST_SKIPPED;
	}

	tab = calloc(SIZE, sizeof(float));

	starpu_vector_data_register(&tab_handle, STARPU_MAIN_RAM, (uintptr_t)tab, SIZE, sizeof(float));

	int nloops = NITER;
	int loop;
	int other_rank = rank%2 == 0 ? rank+1 : rank-1;

	for (loop = 0; loop < nloops; loop++)
	{
		if ((loop % 2) == (rank%2))
		{
			//FPRINTF_MPI(stderr, "Sending to %d\n", other_rank);
			starpu_mpi_send(tab_handle, other_rank, loop, MPI_COMM_WORLD);
		}
		else
		{
			MPI_Status status;
			//FPRINTF_MPI(stderr, "Receiving from %d\n", other_rank);
			starpu_mpi_recv(tab_handle, other_rank, loop, MPI_COMM_WORLD, &status);
		}
	}

	starpu_data_unregister(tab_handle);
	free(tab);

	starpu_mpi_shutdown();
	starpu_shutdown();
	MPI_Finalize();

	return 0;
}