Page Menu
Home
c4science
Search
Configure Global Search
Log In
Files
F85160979
pair_lj_cut_coul_long_opt.cpp
No One
Temporary
Actions
Download File
Edit File
Delete File
View Transforms
Subscribe
Mute Notifications
Award Token
Subscribers
None
File Metadata
Details
File Info
Storage
Attached
Created
Fri, Sep 27, 04:58
Size
5 KB
Mime Type
text/x-c
Expires
Sun, Sep 29, 04:58 (1 d, 23 h)
Engine
blob
Format
Raw Data
Handle
21136495
Attached To
rLAMMPS lammps
pair_lj_cut_coul_long_opt.cpp
View Options
/* ----------------------------------------------------------------------
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 <math.h>
#include "pair_lj_cut_coul_long_opt.h"
#include "atom.h"
#include "force.h"
#include "neigh_list.h"
using namespace LAMMPS_NS;
#define EWALD_F 1.12837917
#define EWALD_P 0.3275911
#define A1 0.254829592
#define A2 -0.284496736
#define A3 1.421413741
#define A4 -1.453152027
#define A5 1.061405429
/* ---------------------------------------------------------------------- */
PairLJCutCoulLongOpt::PairLJCutCoulLongOpt(LAMMPS *lmp) : PairLJCutCoulLong(lmp)
{
respa_enable = 0;
}
/* ---------------------------------------------------------------------- */
void PairLJCutCoulLongOpt::compute(int eflag, int vflag)
{
if (eflag || vflag) ev_setup(eflag,vflag);
else evflag = vflag_fdotr = 0;
if (!ncoultablebits) {
if (evflag) {
if (eflag) {
if (force->newton_pair) return eval<1,1,1,0>();
else return eval<1,1,0,0>();
} else {
if (force->newton_pair) return eval<1,0,1,0>();
else return eval<1,0,0,0>();
}
} else {
if (force->newton_pair) return eval<0,0,1,0>();
else return eval<0,0,0,0>();
}
} else {
if (evflag) {
if (eflag) {
if (force->newton_pair) return eval<1,1,1,1>();
else return eval<1,1,0,1>();
} else {
if (force->newton_pair) return eval<1,0,1,1>();
else return eval<1,0,0,1>();
}
} else {
if (force->newton_pair) return eval<0,0,1,1>();
else return eval<0,0,0,1>();
}
}
}
template < const int EVFLAG, const int EFLAG,
const int NEWTON_PAIR, const int CTABLE >
void PairLJCutCoulLongOpt::eval()
{
int i,ii,j,jj,inum,jnum,itype,jtype,itable;
double qtmp,xtmp,ytmp,ztmp,delx,dely,delz,evdwl,ecoul,fpair;
double fraction,table;
double r,r2inv,r6inv,forcecoul,forcelj,factor_coul,factor_lj;
double grij,expm2,prefactor,t,erfc;
int *ilist,*jlist,*numneigh,**firstneigh;
double rsq;
evdwl = ecoul = 0.0;
double **x = atom->x;
double **f = atom->f;
double *q = atom->q;
int *type = atom->type;
int nlocal = atom->nlocal;
double *special_coul = force->special_coul;
double *special_lj = force->special_lj;
double qqrd2e = force->qqrd2e;
double fxtmp,fytmp,fztmp;
inum = list->inum;
ilist = list->ilist;
numneigh = list->numneigh;
firstneigh = list->firstneigh;
// loop over neighbors of my atoms
for (ii = 0; ii < inum; ii++) {
i = ilist[ii];
qtmp = q[i];
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
itype = type[i];
jlist = firstneigh[i];
jnum = numneigh[i];
fxtmp = fytmp = fztmp = 0.0;
for (jj = 0; jj < jnum; jj++) {
j = jlist[jj];
factor_lj = special_lj[sbmask(j)];
factor_coul = special_coul[sbmask(j)];
j &= NEIGHMASK;
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
rsq = delx*delx + dely*dely + delz*delz;
jtype = type[j];
if (rsq < cutsq[itype][jtype]) {
r2inv = 1.0/rsq;
if (rsq < cut_coulsq) {
if (!CTABLE || rsq <= tabinnersq) {
r = sqrt(rsq);
grij = g_ewald * r;
expm2 = exp(-grij*grij);
t = 1.0 / (1.0 + EWALD_P*grij);
erfc = t * (A1+t*(A2+t*(A3+t*(A4+t*A5)))) * expm2;
prefactor = qqrd2e * qtmp*q[j]/r;
forcecoul = prefactor * (erfc + EWALD_F*grij*expm2);
if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*prefactor;
} else {
union_int_float_t rsq_lookup;
rsq_lookup.f = rsq;
itable = rsq_lookup.i & ncoulmask;
itable >>= ncoulshiftbits;
fraction = (rsq_lookup.f - rtable[itable]) * drtable[itable];
table = ftable[itable] + fraction*dftable[itable];
forcecoul = qtmp*q[j] * table;
if (factor_coul < 1.0) {
table = ctable[itable] + fraction*dctable[itable];
prefactor = qtmp*q[j] * table;
forcecoul -= (1.0-factor_coul)*prefactor;
}
}
} else forcecoul = 0.0;
if (rsq < cut_ljsq[itype][jtype]) {
r6inv = r2inv*r2inv*r2inv;
forcelj = r6inv * (lj1[itype][jtype]*r6inv - lj2[itype][jtype]);
} else forcelj = 0.0;
fpair = (forcecoul + factor_lj*forcelj) * r2inv;
fxtmp += delx*fpair;
fytmp += dely*fpair;
fztmp += delz*fpair;
if (NEWTON_PAIR || j < nlocal) {
f[j][0] -= delx*fpair;
f[j][1] -= dely*fpair;
f[j][2] -= delz*fpair;
}
if (EFLAG) {
if (rsq < cut_coulsq) {
if (!CTABLE || rsq <= tabinnersq)
ecoul = prefactor*erfc;
else {
table = etable[itable] + fraction*detable[itable];
ecoul = qtmp*q[j] * table;
}
if (factor_coul < 1.0) ecoul -= (1.0-factor_coul)*prefactor;
} else ecoul = 0.0;
if (rsq < cut_ljsq[itype][jtype]) {
evdwl = r6inv*(lj3[itype][jtype]*r6inv-lj4[itype][jtype]) -
offset[itype][jtype];
evdwl *= factor_lj;
} else evdwl = 0.0;
}
if (EVFLAG) ev_tally(i,j,nlocal,NEWTON_PAIR,
evdwl,ecoul,fpair,delx,dely,delz);
}
}
f[i][0] += fxtmp;
f[i][1] += fytmp;
f[i][2] += fztmp;
}
if (vflag_fdotr) virial_fdotr_compute();
}
/* ---------------------------------------------------------------------- */
Event Timeline
Log In to Comment