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lammps/src/USER-DPD/npair_halffull_newton_ssa.cpp
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npair_halffull_newton_ssa.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.
------------------------------------------------------------------------- */
/* ----------------------------------------------------------------------
Contributing authors:
James Larentzos and Timothy I. Mattox (Engility Corporation)
------------------------------------------------------------------------- */
#include "npair_halffull_newton_ssa.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "atom.h"
#include "atom_vec.h"
#include "molecule.h"
#include "domain.h"
#include "my_page.h"
#include "error.h"
using namespace LAMMPS_NS;
// allocate space for static class variable
// prototype for non-class function
static int *ssaAIRptr;
static int cmp_ssaAIR(const void *, const void *);
/* ---------------------------------------------------------------------- */
NPairHalffullNewtonSSA::NPairHalffullNewtonSSA(LAMMPS *lmp) : NPair(lmp) {}
/* ----------------------------------------------------------------------
build half list from full list for use by Shardlow Spliting Algorithm
pair stored once if i,j are both owned and i < j
if j is ghost, only store if j coords are "above and to the right" of i
works if full list is a skip list
------------------------------------------------------------------------- */
void NPairHalffullNewtonSSA::build(NeighList *list)
{
int i,j,ii,jj,n,jnum,joriginal;
int *neighptr,*jlist;
int nlocal = atom->nlocal;
int *ssaAIR = atom->ssaAIR;
int *ilist = list->ilist;
int *numneigh = list->numneigh;
int **firstneigh = list->firstneigh;
MyPage<int> *ipage = list->ipage;
int *ilist_full = list->listfull->ilist;
int *numneigh_full = list->listfull->numneigh;
int **firstneigh_full = list->listfull->firstneigh;
int inum_full = list->listfull->inum;
int inum = 0;
ipage->reset();
// loop over parent full list
for (ii = 0; ii < inum_full; ii++) {
int AIRct[8] = { 0 };
n = 0;
neighptr = ipage->vget();
i = ilist_full[ii];
// loop over full neighbor list
jlist = firstneigh_full[i];
jnum = numneigh_full[i];
for (jj = 0; jj < jnum; jj++) {
joriginal = jlist[jj];
j = joriginal & NEIGHMASK;
if (j < nlocal) {
if (i > j) continue;
++(AIRct[0]);
} else {
if (ssaAIR[j] < 2) continue; // skip ghost atoms not in AIR
++(AIRct[ssaAIR[j] - 1]);
}
neighptr[n++] = joriginal;
}
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");
// sort the locals+ghosts in the neighbor list by their ssaAIR number
ssaAIRptr = atom->ssaAIR;
qsort(&(neighptr[0]), n, sizeof(int), cmp_ssaAIR);
// do a prefix sum on the counts to turn them into indexes
list->ndxAIR_ssa[i][0] = AIRct[0];
for (int ndx = 1; ndx < 8; ++ndx) {
list->ndxAIR_ssa[i][ndx] = AIRct[ndx] + list->ndxAIR_ssa[i][ndx - 1];
}
}
list->inum = inum;
}
/* ----------------------------------------------------------------------
comparison function invoked by qsort()
accesses static class member ssaAIRptr, set before call to qsort()
------------------------------------------------------------------------- */
static int cmp_ssaAIR(const void *iptr, const void *jptr)
{
int i = *((int *) iptr);
int j = *((int *) jptr);
if (ssaAIRptr[i] < ssaAIRptr[j]) return -1;
if (ssaAIRptr[i] > ssaAIRptr[j]) return 1;
return 0;
}
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