neighbor_omp.h
fb16c0eb301blammm-master

neighbor_omp.h
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			/* ----------------------------------------------------------------------
			LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
			http://lammps.sandia.gov, Sandia National Laboratories
			Steve Plimpton, sjplimp@sandia.gov

			Copyright (2003) Sandia Corporation. Under the terms of Contract
			DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
			certain rights in this software. This software is distributed under
			the GNU General Public License.

			See the README file in the top-level LAMMPS directory.
			------------------------------------------------------------------------- */

			#ifndef LMP_NEIGHBOR_OMP_H
			#define LMP_NEIGHBOR_OMP_H

			#if defined(_OPENMP)
			#include <omp.h>
			#endif

			namespace LAMMPS_NS {

			// these macros hide some ugly and redundant OpenMP related stuff
			#if defined(_OPENMP)

			// make sure we have at least one page for each thread
			#define NEIGH_OMP_INIT \
			const int nthreads = comm->nthreads; \
			if (nthreads > list->maxpage) \
			list->add_pages(nthreads - list->maxpage)

			// get thread id and then assign each thread a fixed chunk of atoms
			#define NEIGH_OMP_SETUP(num) \
			{ \
			const int tid = omp_get_thread_num(); \
			const int idelta = 1 + num/nthreads; \
			const int ifrom = tid*idelta; \
			int ito = ifrom + idelta; \
			if (ito > num) \
			ito = num

			#define NEIGH_OMP_CLOSE }

			#else /* !defined(_OPENMP) */

			#define NEIGH_OMP_INIT \
			const int nthreads = comm->nthreads;

			#define NEIGH_OMP_SETUP(num) \
			const int tid = 0; \
			const int ifrom = 0; \
			const int ito = num

			#define NEIGH_OMP_CLOSE

			#endif

			}

			#endif