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lammps/src/GPU/pair_cg_cmm_coul_msm.cpp
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pair_cg_cmm_coul_msm.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.
------------------------------------------------------------------------- */
/* ----------------------------------------------------------------------
CMM coarse grained MD potentials. Coulomb with MSM version.
Contributing author: Mike Brown <brownw@ornl.gov>
------------------------------------------------------------------------- */
#include "string.h"
#include "pair_cg_cmm_coul_msm.h"
#include "memory.h"
#include "atom.h"
#include "force.h"
#include "kspace.h"
using namespace LAMMPS_NS;
enum {C3=0,C4=1};
/* ---------------------------------------------------------------------- */
PairCGCMMCoulMSM::PairCGCMMCoulMSM(LAMMPS *lmp) : PairCMMCommon(lmp)
{
respa_enable = 0;
single_enable = 0;
}
/* ---------------------------------------------------------------------- */
PairCGCMMCoulMSM::~PairCGCMMCoulMSM()
{
if (allocated_coul) {
memory->destroy(cut_lj);
memory->destroy(cut_ljsq);
memory->destroy(cut_coul);
memory->destroy(cut_coulsq);
allocated_coul=0;
}
}
/* ---------------------------------------------------------------------- */
void PairCGCMMCoulMSM::allocate()
{
PairCMMCommon::allocate();
allocated_coul = 1;
int n = atom->ntypes;
memory->create(cut_lj,n+1,n+1,"paircg:cut_lj");
memory->create(cut_ljsq,n+1,n+1,"paircg:cut_ljsq");
memory->create(cut_coul,n+1,n+1,"paircg:cut_coul");
memory->create(cut_coulsq,n+1,n+1,"paircg:cut_coulsq");
}
/* ----------------------------------------------------------------------
global settings
------------------------------------------------------------------------- */
void PairCGCMMCoulMSM::settings(int narg, char **arg)
{
// strip off smoothing type and send args to parent
if (narg < 1) error->all(FLERR,"Illegal pair_style command");
if (strcmp(arg[0],"C3") == 0)
_smooth = C3;
else if (strcmp(arg[0],"C4") == 0)
_smooth = C4;
else error->all(FLERR,"Illegal pair_style command");
PairCMMCommon::settings(narg-1,&arg[1]);
}
/* ---------------------------------------------------------------------- */
void PairCGCMMCoulMSM::init_style()
{
if (!atom->q_flag)
error->all(FLERR,"Pair style cg/cut/coul/msm requires atom attribute q");
PairCMMCommon::init_style();
_ia=-1.0/cut_coul_global;
_ia2=_ia*_ia;
_ia3=_ia2*_ia;
cut_respa = NULL;
}
/* ---------------------------------------------------------------------- */
double PairCGCMMCoulMSM::init_one(int i, int j)
{
double mycut = PairCMMCommon::init_one(i,j);
return mycut;
}
/* ---------------------------------------------------------------------- */
void PairCGCMMCoulMSM::compute(int eflag, int vflag)
{
int i,j,ii,jj,inum,jnum,itype,jtype,itable;
double qtmp,xtmp,ytmp,ztmp,delx,dely,delz;
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;
if (eflag || vflag) ev_setup(eflag,vflag);
else evflag = vflag_fdotr = 0;
double **x = atom->x;
double **f = atom->f;
double *q = atom->q;
int *type = atom->type;
int nlocal = atom->nlocal;
int nall = nlocal + atom->nghost;
double *special_coul = force->special_coul;
double *special_lj = force->special_lj;
double qqrd2e = force->qqrd2e;
int newton_pair = force->newton_pair;
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];
for (jj = 0; jj < jnum; jj++) {
j = jlist[jj];
factor_lj = special_lj[sbmask(j)];
factor_coul = special_coul[sbmask(j)];
j &= NEIGHMASK;
const double delx = xtmp - x[j][0];
const double dely = ytmp - x[j][1];
const double delz = ztmp - x[j][2];
const double rsq = delx*delx + dely*dely + delz*delz;
const int jtype = type[j];
double evdwl = 0.0;
double ecoul = 0.0;
double fpair = 0.0;
if (rsq < cutsq[itype][jtype]) {
const double r2inv = 1.0/rsq;
const int cgt=cg_type[itype][jtype];
double forcelj = 0.0;
double forcecoul = 0.0;
if (rsq < cut_ljsq[itype][jtype]) {
forcelj=factor_lj;
if (eflag) evdwl=factor_lj;
if (cgt == CG_LJ12_4) {
const double r4inv=r2inv*r2inv;
forcelj *= r4inv*(lj1[itype][jtype]*r4inv*r4inv
- lj2[itype][jtype]);
if (eflag) {
evdwl *= r4inv*(lj3[itype][jtype]*r4inv*r4inv
- lj4[itype][jtype]) - offset[itype][jtype];
}
} else if (cgt == CG_LJ9_6) {
const double r3inv = r2inv*sqrt(r2inv);
const double r6inv = r3inv*r3inv;
forcelj *= r6inv*(lj1[itype][jtype]*r3inv
- lj2[itype][jtype]);
if (eflag) {
evdwl *= r6inv*(lj3[itype][jtype]*r3inv
- lj4[itype][jtype]) - offset[itype][jtype];
}
} else {
const double r6inv = r2inv*r2inv*r2inv;
forcelj *= r6inv*(lj1[itype][jtype]*r6inv
- lj2[itype][jtype]);
if (eflag) {
evdwl *= r6inv*(lj3[itype][jtype]*r6inv
- lj4[itype][jtype]) - offset[itype][jtype];
}
}
}
if (rsq < cut_coulsq_global) {
const double ir = 1.0/sqrt(rsq);
const double prefactor = qqrd2e * qtmp*q[j];
const double r2_ia2 = rsq*_ia2;
const double r4_ia4 = r2_ia2*r2_ia2;
if (_smooth==C3) {
forcecoul = prefactor*(_ia3*(-4.375+5.25*r2_ia2-1.875*r4_ia4)-
ir/rsq);
if (eflag)
ecoul = prefactor*(ir+_ia*(2.1875-2.1875*r2_ia2+
1.3125*r4_ia4-0.3125*r2_ia2*r4_ia4));
} else {
const double r6_ia6 = r2_ia2*r4_ia4;
forcecoul = prefactor*(_ia3*(-6.5625+11.8125*r2_ia2-8.4375*r4_ia4+
2.1875*r6_ia6)-ir/rsq);
if (eflag)
ecoul = prefactor*(ir+_ia*(2.4609375-3.28125*r2_ia2+
2.953125*r4_ia4-1.40625*r6_ia6+
0.2734375*r4_ia4*r4_ia4));
}
if (factor_coul < 1.0) {
forcecoul -= (1.0-factor_coul)*prefactor*ir;
if (eflag) ecoul -= (1.0-factor_coul)*prefactor*ir;
}
}
fpair = forcecoul + forcelj * r2inv;
f[i][0] += delx*fpair;
f[i][1] += dely*fpair;
f[i][2] += delz*fpair;
if (newton_pair || j < nlocal) {
f[j][0] -= delx*fpair;
f[j][1] -= dely*fpair;
f[j][2] -= delz*fpair;
}
if (evflag) ev_tally(i,j,nlocal,newton_pair,
evdwl,ecoul,fpair,delx,dely,delz);
}
}
}
if (vflag_fdotr) virial_fdotr_compute();
}
/* ---------------------------------------------------------------------- */
void PairCGCMMCoulMSM::write_restart(FILE *fp)
{
write_restart_settings(fp);
PairCMMCommon::write_restart(fp);
}
/* ---------------------------------------------------------------------- */
void PairCGCMMCoulMSM::read_restart(FILE *fp)
{
read_restart_settings(fp);
allocate();
PairCMMCommon::read_restart(fp);
}
/* ---------------------------------------------------------------------- */
double PairCGCMMCoulMSM::memory_usage()
{
double bytes=PairCMMCommon::memory_usage();
int n = atom->ntypes;
// cut_coul/cut_coulsq/cut_ljsq
bytes += (n+1)*(n+1)*sizeof(double)*4;
return bytes;
}
/* ---------------------------------------------------------------------- */
void *PairCGCMMCoulMSM::extract(char *str)
{
if (strcmp(str,"cut_coul") == 0) return (void *) &cut_coul_global;
return NULL;
}
/* ---------------------------------------------------------------------- */
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