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lammps/src/USER-OMP/neigh_half_nsq_omp.cpp
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neigh_half_nsq_omp.cpp
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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.
------------------------------------------------------------------------- */
#include "neighbor.h"
#include "neighbor_omp.h"
#include "neigh_list.h"
#include "atom.h"
#include "comm.h"
#include "domain.h"
#include "group.h"
#include "error.h"
using namespace LAMMPS_NS;
/* ----------------------------------------------------------------------
N^2 / 2 search for neighbor pairs with partial Newton's 3rd law
pair stored once if i,j are both owned and i < j
pair stored by me if j is ghost (also stored by proc owning j)
------------------------------------------------------------------------- */
void Neighbor::half_nsq_no_newton_omp(NeighList *list)
{
const int nlocal = (includegroup) ? atom->nfirst : atom->nlocal;
const int bitmask = (includegroup) ? group->bitmask[includegroup] : 0;
const int nall = atom->nlocal + atom->nghost;
NEIGH_OMP_INIT;
#if defined(_OPENMP)
#pragma omp parallel default(none) shared(list)
#endif
NEIGH_OMP_SETUP(nlocal);
int i,j,n,itype,jtype,which;
double xtmp,ytmp,ztmp,delx,dely,delz,rsq;
int *neighptr;
int **special = atom->special;
int **nspecial = atom->nspecial;
int *tag = atom->tag;
double **x = atom->x;
int *type = atom->type;
int *mask = atom->mask;
int *molecule = atom->molecule;
int molecular = atom->molecular;
int *ilist = list->ilist;
int *numneigh = list->numneigh;
int **firstneigh = list->firstneigh;
// each thread works on its own page
int npage = tid;
int npnt = 0;
// loop over owned atoms, storing neighbors
for (i = ifrom; i < ito; i++) {
#if defined(_OPENMP)
#pragma omp critical
#endif
if (pgsize - npnt < oneatom) {
npnt = 0;
npage += nthreads;
if (npage >= list->maxpage) list->add_pages(nthreads);
}
neighptr = &(list->pages[npage][npnt]);
n = 0;
itype = type[i];
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
// loop over remaining atoms, owned and ghost
// only store pair if i < j
for (j = i+1; j < nall; j++) {
if (includegroup && !(mask[j] & bitmask)) continue;
jtype = type[j];
if (exclude && exclusion(i,j,itype,jtype,mask,molecule)) continue;
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
rsq = delx*delx + dely*dely + delz*delz;
if (rsq <= cutneighsq[itype][jtype]) {
if (molecular) {
which = find_special(special[i],nspecial[i],tag[j]);
if (which == 0) neighptr[n++] = j;
else if (domain->minimum_image_check(delx,dely,delz))
neighptr[n++] = j;
else if (which > 0) neighptr[n++] = j ^ (which << SBBITS);
} else neighptr[n++] = j;
}
}
ilist[i] = i;
firstneigh[i] = neighptr;
numneigh[i] = n;
npnt += n;
if (n > oneatom)
error->one(FLERR,"Neighbor list overflow, boost neigh_modify one");
}
NEIGH_OMP_CLOSE;
list->inum = nlocal;
}
/* ----------------------------------------------------------------------
N^2 / 2 search for neighbor pairs with partial Newton's 3rd law
include neighbors of ghost atoms, but no "special neighbors" for ghosts
pair stored once if i,j are both owned and i < j
pair stored by me if i owned and j ghost (also stored by proc owning j)
pair stored once if i,j are both ghost and i < j
------------------------------------------------------------------------- */
void Neighbor::half_nsq_no_newton_ghost_omp(NeighList *list)
{
const int nlocal = (includegroup) ? atom->nfirst : atom->nlocal;
const int bitmask = (includegroup) ? group->bitmask[includegroup] : 0;
const int nall = nlocal + atom->nghost;
NEIGH_OMP_INIT;
#if defined(_OPENMP)
#pragma omp parallel default(none) shared(list)
#endif
NEIGH_OMP_SETUP(nall);
int i,j,n,itype,jtype,which;
double xtmp,ytmp,ztmp,delx,dely,delz,rsq;
int *neighptr;
int **special = atom->special;
int **nspecial = atom->nspecial;
int *tag = atom->tag;
double **x = atom->x;
int *type = atom->type;
int *mask = atom->mask;
int *molecule = atom->molecule;
int molecular = atom->molecular;
int *ilist = list->ilist;
int *numneigh = list->numneigh;
int **firstneigh = list->firstneigh;
// each thread works on its own page
int npage = tid;
int npnt = 0;
// loop over owned & ghost atoms, storing neighbors
for (i = ifrom; i < ito; i++) {
#if defined(_OPENMP)
#pragma omp critical
#endif
if (pgsize - npnt < oneatom) {
npnt = 0;
npage += nthreads;
if (npage >= list->maxpage) list->add_pages(nthreads);
}
neighptr = &(list->pages[npage][npnt]);
n = 0;
itype = type[i];
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
// loop over remaining atoms, owned and ghost
// only store pair if i < j
// stores own/own pairs only once
// stores own/ghost pairs with owned atom only, on both procs
// stores ghost/ghost pairs only once
// no molecular test when i = ghost atom
if (i < nlocal) {
for (j = i+1; j < nall; j++) {
if (includegroup && !(mask[j] & bitmask)) continue;
jtype = type[j];
if (exclude && exclusion(i,j,itype,jtype,mask,molecule)) continue;
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
rsq = delx*delx + dely*dely + delz*delz;
if (rsq <= cutneighsq[itype][jtype]) {
if (molecular) {
which = find_special(special[i],nspecial[i],tag[j]);
if (which == 0) neighptr[n++] = j;
else if (domain->minimum_image_check(delx,dely,delz))
neighptr[n++] = j;
else if (which > 0) neighptr[n++] = j ^ (which << SBBITS);
} else neighptr[n++] = j;
}
}
} else {
for (j = i+1; j < nall; j++) {
if (includegroup && !(mask[j] & bitmask)) continue;
jtype = type[j];
if (exclude && exclusion(i,j,itype,jtype,mask,molecule)) continue;
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
rsq = delx*delx + dely*dely + delz*delz;
if (rsq <= cutneighsq[itype][jtype]) neighptr[n++] = j;
}
}
ilist[i] = i;
firstneigh[i] = neighptr;
numneigh[i] = n;
npnt += n;
if (n > oneatom)
error->one(FLERR,"Neighbor list overflow, boost neigh_modify one");
}
NEIGH_OMP_CLOSE;
list->inum = atom->nlocal;
list->gnum = nall - atom->nlocal;
}
/* ----------------------------------------------------------------------
N^2 / 2 search for neighbor pairs with full Newton's 3rd law
every pair stored exactly once by some processor
decision on ghost atoms based on itag,jtag tests
------------------------------------------------------------------------- */
void Neighbor::half_nsq_newton_omp(NeighList *list)
{
const int nlocal = (includegroup) ? atom->nfirst : atom->nlocal;
const int bitmask = (includegroup) ? group->bitmask[includegroup] : 0;
NEIGH_OMP_INIT;
#if defined(_OPENMP)
#pragma omp parallel default(none) shared(list)
#endif
NEIGH_OMP_SETUP(nlocal);
int i,j,n,itype,jtype,itag,jtag,which;
double xtmp,ytmp,ztmp,delx,dely,delz,rsq;
int *neighptr;
// loop over each atom, storing neighbors
int **special = atom->special;
int **nspecial = atom->nspecial;
int *tag = atom->tag;
double **x = atom->x;
int *type = atom->type;
int *mask = atom->mask;
int *molecule = atom->molecule;
int nall = atom->nlocal + atom->nghost;
int molecular = atom->molecular;
int *ilist = list->ilist;
int *numneigh = list->numneigh;
int **firstneigh = list->firstneigh;
int npage = tid;
int npnt = 0;
for (i = ifrom; i < ito; i++) {
#if defined(_OPENMP)
#pragma omp critical
#endif
if (pgsize - npnt < oneatom) {
npnt = 0;
npage += nthreads;
if (npage >= list->maxpage) list->add_pages(nthreads);
}
neighptr = &(list->pages[npage][npnt]);
n = 0;
itag = tag[i];
itype = type[i];
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
// loop over remaining atoms, owned and ghost
// itag = jtag is possible for long cutoffs that include images of self
for (j = i+1; j < nall; j++) {
if (includegroup && !(mask[j] & bitmask)) continue;
if (j >= nlocal) {
jtag = tag[j];
if (itag > jtag) {
if ((itag+jtag) % 2 == 0) continue;
} else if (itag < jtag) {
if ((itag+jtag) % 2 == 1) continue;
} else {
if (x[j][2] < ztmp) continue;
if (x[j][2] == ztmp) {
if (x[j][1] < ytmp) continue;
if (x[j][1] == ytmp && x[j][0] < xtmp) continue;
}
}
}
jtype = type[j];
if (exclude && exclusion(i,j,itype,jtype,mask,molecule)) continue;
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
rsq = delx*delx + dely*dely + delz*delz;
if (rsq <= cutneighsq[itype][jtype]) {
if (molecular) {
which = find_special(special[i],nspecial[i],tag[j]);
if (which == 0) neighptr[n++] = j;
else if (domain->minimum_image_check(delx,dely,delz))
neighptr[n++] = j;
else if (which > 0) neighptr[n++] = j ^ (which << SBBITS);
} else neighptr[n++] = j;
}
}
ilist[i] = i;
firstneigh[i] = neighptr;
numneigh[i] = n;
npnt += n;
if (n > oneatom)
error->one(FLERR,"Neighbor list overflow, boost neigh_modify one");
}
NEIGH_OMP_CLOSE;
list->inum = nlocal;
}
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