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lammps/src/USER-OMP/pair_line_lj_omp.cpp
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pair_line_lj_omp.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 author: Axel Kohlmeyer (Temple U)
------------------------------------------------------------------------- */
#include "math.h"
#include "pair_line_lj_omp.h"
#include "atom.h"
#include "comm.h"
#include "force.h"
#include "memory.h"
#include "neighbor.h"
#include "neigh_list.h"
#include <string.h>
#include "suffix.h"
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
PairLineLJOMP::PairLineLJOMP(LAMMPS *lmp) :
PairLineLJ(lmp), ThrOMP(lmp, THR_PAIR)
{
suffix_flag |= Suffix::OMP;
respa_enable = 0;
}
/* ---------------------------------------------------------------------- */
void PairLineLJOMP::compute(int eflag, int vflag)
{
if (eflag || vflag) {
ev_setup(eflag,vflag);
} else evflag = vflag_fdotr = 0;
const int nall = atom->nlocal + atom->nghost;
const int nthreads = comm->nthreads;
const int inum = list->inum;
const int * const line = atom->line;
const int * const type = atom->type;
// grow discrete list if necessary and initialize
if (nall > nmax) {
nmax = nall;
memory->destroy(dnum);
memory->destroy(dfirst);
memory->create(dnum,nall,"pair:dnum");
memory->create(dfirst,nall,"pair:dfirst");
}
memset(dnum,0,nall*sizeof(int));
ndiscrete = 0;
// need to discretize the system ahead of time
// until we find a good way to multi-thread it.
for (int i = 0; i < nall; ++i)
if (line[i] >= 0)
if (dnum[i] == 0)
discretize(i,sigma[type[i]][type[i]]);
#if defined(_OPENMP)
#pragma omp parallel default(none) shared(eflag,vflag)
#endif
{
int ifrom, ito, tid;
loop_setup_thr(ifrom, ito, tid, inum, nthreads);
ThrData *thr = fix->get_thr(tid);
ev_setup_thr(eflag, vflag, nall, eatom, vatom, thr);
if (evflag) {
if (eflag) {
if (force->newton_pair) eval<1,1,1>(ifrom, ito, thr);
else eval<1,1,0>(ifrom, ito, thr);
} else {
if (force->newton_pair) eval<1,0,1>(ifrom, ito, thr);
else eval<1,0,0>(ifrom, ito, thr);
}
} else {
if (force->newton_pair) eval<0,0,1>(ifrom, ito, thr);
else eval<0,0,0>(ifrom, ito, thr);
}
reduce_thr(this, eflag, vflag, thr);
} // end of omp parallel region
}
template <int EVFLAG, int EFLAG, int NEWTON_PAIR>
void PairLineLJOMP::eval(int iifrom, int iito, ThrData * const thr)
{
int i,j,ii,jj,jnum,itype,jtype;
int ni,nj,npi,npj,ifirst,jfirst;
double xtmp,ytmp,ztmp,delx,dely,delz,evdwl,fpair;
double rsq,r2inv,r6inv,term1,term2,sig,sig3,forcelj;
double xi[2],xj[2],fi[2],fj[2],dxi,dxj,dyi,dyj,ti,tj;
int *ilist,*jlist,*numneigh,**firstneigh;
const double * const * const x = atom->x;
double * const * const f = thr->get_f();
double * const * const torque = thr->get_torque();
const int * const line = atom->line;
const int * const type = atom->type;
const int nlocal = atom->nlocal;
ilist = list->ilist;
numneigh = list->numneigh;
firstneigh = list->firstneigh;
// loop over neighbors of my atoms
for (ii = iifrom; ii < iito; ++ii) {
i = ilist[ii];
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];
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]) continue;
// line/line interactions = NxN particles
evdwl = 0.0;
if (line[i] >= 0 && line[j] >= 0) {
npi = dnum[i];
ifirst = dfirst[i];
npj = dnum[j];
jfirst = dfirst[j];
fi[0] = fi[1] = fj[0] = fj[1] = ti = tj = 0.0;
for (ni = 0; ni < npi; ni++) {
dxi = discrete[ifirst+ni].dx;
dyi = discrete[ifirst+ni].dy;
for (nj = 0; nj < npj; nj++) {
dxj = discrete[jfirst+nj].dx;
dyj = discrete[jfirst+nj].dy;
xi[0] = x[i][0] + dxi;
xi[1] = x[i][1] + dyi;
xj[0] = x[j][0] + dxj;
xj[1] = x[j][1] + dyj;
delx = xi[0] - xj[0];
dely = xi[1] - xj[1];
rsq = delx*delx + dely*dely;
sig = 0.5 * (discrete[ifirst+ni].sigma+discrete[jfirst+nj].sigma);
sig3 = sig*sig*sig;
term2 = 24.0*epsilon[itype][jtype] * sig3*sig3;
term1 = 2.0 * term2 * sig3*sig3;
r2inv = 1.0/rsq;
r6inv = r2inv*r2inv*r2inv;
forcelj = r6inv * (term1*r6inv - term2);
fpair = forcelj*r2inv;
if (EFLAG) evdwl += r6inv*(term1/12.0*r6inv-term2/6.0);
fi[0] += delx*fpair;
fi[1] += dely*fpair;
ti += fpair*(dxi*dely - dyi*delx);
if (NEWTON_PAIR || j < nlocal) {
fj[0] -= delx*fpair;
fj[1] -= dely*fpair;
tj += fpair*(dxj*dely - dyj*delx);
}
}
}
f[i][0] += fi[0];
f[i][1] += fi[1];
f[j][0] += fj[0];
f[j][1] += fj[1];
torque[i][2] += ti;
torque[j][2] += tj;
// line/particle interaction = Nx1 particles
// convert line into Np particles based on sigma and line length
} else if (line[i] >= 0) {
npi = dnum[i];
ifirst = dfirst[i];
fi[0] = fi[1] = fj[0] = fj[1] = ti = tj = 0.0;
for (ni = 0; ni < npi; ni++) {
dxi = discrete[ifirst+ni].dx;
dyi = discrete[ifirst+ni].dy;
xi[0] = x[i][0] + dxi;
xi[1] = x[i][1] + dyi;
xj[0] = x[j][0];
xj[1] = x[j][1];
delx = xi[0] - xj[0];
dely = xi[1] - xj[1];
rsq = delx*delx + dely*dely;
sig = 0.5 * (discrete[ifirst+ni].sigma+sigma[jtype][jtype]);
sig3 = sig*sig*sig;
term2 = 24.0*epsilon[itype][jtype] * sig3*sig3;
term1 = 2.0 * term2 * sig3*sig3;
r2inv = 1.0/rsq;
r6inv = r2inv*r2inv*r2inv;
forcelj = r6inv * (term1*r6inv - term2);
fpair = forcelj*r2inv;
if (EFLAG) evdwl += r6inv*(term1/12.0*r6inv-term2/6.0);
fi[0] += delx*fpair;
fi[1] += dely*fpair;
ti += fpair*(dxi*dely - dyi*delx);
if (NEWTON_PAIR || j < nlocal) {
fj[0] -= delx*fpair;
fj[1] -= dely*fpair;
tj += fpair*(dxj*dely - dyj*delx);
}
}
f[i][0] += fi[0];
f[i][1] += fi[1];
f[j][0] += fj[0];
f[j][1] += fj[1];
torque[i][2] += ti;
torque[j][2] += tj;
// particle/line interaction = Nx1 particles
// convert line into Np particles based on sigma and line length
} else if (line[j] >= 0) {
npj = dnum[j];
jfirst = dfirst[j];
fi[0] = fi[1] = fj[0] = fj[1] = ti = tj = 0.0;
for (nj = 0; nj < npj; nj++) {
dxj = discrete[jfirst+nj].dx;
dyj = discrete[jfirst+nj].dy;
xi[0] = x[i][0];
xi[1] = x[i][1];
xj[0] = x[j][0] + dxj;
xj[1] = x[j][1] + dyj;
delx = xi[0] - xj[0];
dely = xi[1] - xj[1];
rsq = delx*delx + dely*dely;
sig = 0.5 * (sigma[itype][itype]+discrete[jfirst+nj].sigma);
sig3 = sig*sig*sig;
term2 = 24.0*epsilon[itype][jtype] * sig3*sig3;
term1 = 2.0 * term2 * sig3*sig3;
r2inv = 1.0/rsq;
r6inv = r2inv*r2inv*r2inv;
forcelj = r6inv * (term1*r6inv - term2);
fpair = forcelj*r2inv;
if (EFLAG) evdwl += r6inv*(term1/12.0*r6inv-term2/6.0);
fi[0] += delx*fpair;
fi[1] += dely*fpair;
ti += fpair*(dxi*dely - dyi*delx);
if (NEWTON_PAIR || j < nlocal) {
fj[0] -= delx*fpair;
fj[1] -= dely*fpair;
tj -= fpair*(dxj*dely - dyj*delx);
}
}
f[i][0] += fi[0];
f[i][1] += fi[1];
f[j][0] += fj[0];
f[j][1] += fj[1];
torque[i][2] += ti;
torque[j][2] += tj;
// particle/particle interaction = 1x1 particles
} else {
r2inv = 1.0/rsq;
r6inv = r2inv*r2inv*r2inv;
forcelj = r6inv * (lj1[itype][jtype]*r6inv - lj2[itype][jtype]);
fpair = forcelj*r2inv;
if (EFLAG)
evdwl += r6inv*(lj3[itype][jtype]*r6inv-lj4[itype][jtype]);
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_thr(this,i,j,nlocal,NEWTON_PAIR,
evdwl,0.0,fpair,delx,dely,delz,thr);
}
}
}
/* ---------------------------------------------------------------------- */
double PairLineLJOMP::memory_usage()
{
double bytes = memory_usage_thr();
bytes += PairLineLJ::memory_usage();
return bytes;
}
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