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lammps/src/compute_coord_atom.cpp
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compute_coord_atom.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 "stdlib.h"
#include "compute_coord_atom.h"
#include "atom.h"
#include "modify.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "neigh_request.h"
#include "force.h"
#include "pair.h"
#include "comm.h"
#include "memory.h"
#include "error.h"
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
ComputeCoordAtom::ComputeCoordAtom(LAMMPS *lmp, int narg, char **arg) :
Compute(lmp, narg, arg)
{
if (narg != 4) error->all("Illegal compute coord/atom command");
cutoff = atof(arg[3]);
peratom_flag = 1;
size_peratom = 0;
nmax = 0;
coordination = NULL;
}
/* ---------------------------------------------------------------------- */
ComputeCoordAtom::~ComputeCoordAtom()
{
memory->sfree(coordination);
}
/* ---------------------------------------------------------------------- */
void ComputeCoordAtom::init()
{
if (force->pair == NULL || cutoff > force->pair->cutforce)
error->all("Compute coord/atom cutoff is longer than pairwise cutoff");
// need an occasional full neighbor list
int irequest = neighbor->request((void *) this);
neighbor->requests[irequest]->pair = 0;
neighbor->requests[irequest]->compute = 1;
neighbor->requests[irequest]->half = 0;
neighbor->requests[irequest]->full = 1;
neighbor->requests[irequest]->occasional = 1;
int count = 0;
for (int i = 0; i < modify->ncompute; i++)
if (strcmp(modify->compute[i]->style,"coord/atom") == 0) count++;
if (count > 1 && comm->me == 0)
error->warning("More than one compute coord/atom");
}
/* ---------------------------------------------------------------------- */
void ComputeCoordAtom::init_list(int id, NeighList *ptr)
{
list = ptr;
}
/* ---------------------------------------------------------------------- */
void ComputeCoordAtom::compute_peratom()
{
int i,j,ii,jj,inum,jnum,n;
double xtmp,ytmp,ztmp,delx,dely,delz,rsq;
int *ilist,*jlist,*numneigh,**firstneigh;
// grow coordination array if necessary
if (atom->nlocal > nmax) {
memory->sfree(coordination);
nmax = atom->nmax;
coordination = (double *)
memory->smalloc(nmax*sizeof(double),"compute/coord/atom:coordination");
scalar_atom = coordination;
}
// invoke full neighbor list (will copy or build if necessary)
neighbor->build_one(list->index);
inum = list->inum;
ilist = list->ilist;
numneigh = list->numneigh;
firstneigh = list->firstneigh;
// compute coordination number for each atom in group
// use full neighbor list to count atoms less than cutoff
double **x = atom->x;
int *mask = atom->mask;
int nlocal = atom->nlocal;
int nall = atom->nlocal + atom->nghost;
double cutsq = cutoff*cutoff;
for (ii = 0; ii < inum; ii++) {
i = ilist[ii];
if (mask[i] & groupbit) {
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
jlist = firstneigh[i];
jnum = numneigh[i];
n = 0;
for (jj = 0; jj < jnum; jj++) {
j = jlist[jj];
if (j >= nall) j %= nall;
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
rsq = delx*delx + dely*dely + delz*delz;
if (rsq < cutsq) n++;
}
coordination[i] = n;
} else coordination[i] = 0.0;
}
}
/* ----------------------------------------------------------------------
memory usage of local atom-based array
------------------------------------------------------------------------- */
double ComputeCoordAtom::memory_usage()
{
double bytes = nmax * sizeof(double);
return bytes;
}
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