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lammps/src/npair_half_size_nsq_newtoff.cpp
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npair_half_size_nsq_newtoff.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 <string.h>
#include "npair_half_size_nsq_newtoff.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "atom.h"
#include "atom_vec.h"
#include "group.h"
#include "my_page.h"
#include "error.h"
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
NPairHalfSizeNsqNewtoff::NPairHalfSizeNsqNewtoff(LAMMPS *lmp) : NPair(lmp) {}
/* ----------------------------------------------------------------------
size particles
N^2 / 2 search for neighbor pairs with partial Newton's 3rd law
pair added to list if atoms i and j are both owned and i < j
pair added if j is ghost (also stored by proc owning j)
------------------------------------------------------------------------- */
void NPairHalfSizeNsqNewtoff::build(NeighList *list)
{
int i,j,m,n,nn,bitmask;
double xtmp,ytmp,ztmp,delx,dely,delz,rsq;
double radi,radsum,cutsq;
int *neighptr;
double **x = atom->x;
double *radius = atom->radius;
tagint *tag = atom->tag;
int *type = atom->type;
int *mask = atom->mask;
tagint *molecule = atom->molecule;
int nlocal = atom->nlocal;
int nall = nlocal + atom->nghost;
if (includegroup) {
nlocal = atom->nfirst;
bitmask = group->bitmask[includegroup];
}
int history = list->history;
int *ilist = list->ilist;
int *numneigh = list->numneigh;
int **firstneigh = list->firstneigh;
MyPage<int> *ipage = list->ipage;
int mask_history = 3 << SBBITS;
int inum = 0;
ipage->reset();
for (i = 0; i < nlocal; i++) {
n = 0;
neighptr = ipage->vget();
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
radi = radius[i];
// loop over remaining atoms, owned and ghost
for (j = i+1; j < nall; j++) {
if (includegroup && !(mask[j] & bitmask)) continue;
if (exclude && exclusion(i,j,type[i],type[j],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;
radsum = radi + radius[j];
cutsq = (radsum+skin) * (radsum+skin);
if (rsq <= cutsq) {
if (history && rsq < radsum*radsum)
neighptr[n++] = j ^ mask_history;
else
neighptr[n++] = j;
}
}
ilist[inum++] = i;
firstneigh[i] = neighptr;
numneigh[i] = n;
ipage->vgot(n);
if (ipage->status())
error->one(FLERR,"Neighbor list overflow, boost neigh_modify one");
}
list->inum = inum;
}
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