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lammps/src/USER-OMP/bond_harmonic_shift_cut_omp.cpp
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bond_harmonic_shift_cut_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 "lmptype.h"
#include "bond_harmonic_shift_cut_omp.h"
#include "atom.h"
#include "comm.h"
#include "force.h"
#include "neighbor.h"
#include "domain.h"
#include <math.h>
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
void BondHarmonicShiftCutOMP::compute(int eflag, int vflag)
{
if (eflag || vflag) {
ev_setup(eflag,vflag);
} else evflag = 0;
const int nall = atom->nlocal + atom->nghost;
const int nthreads = comm->nthreads;
const int inum = neighbor->nbondlist;
#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_bond) eval<1,1,1>(ifrom, ito, thr);
else eval<1,1,0>(ifrom, ito, thr);
} else {
if (force->newton_bond) eval<1,0,1>(ifrom, ito, thr);
else eval<1,0,0>(ifrom, ito, thr);
}
} else {
if (force->newton_bond) 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_BOND>
void BondHarmonicShiftCutOMP::eval(int nfrom, int nto, ThrData * const thr)
{
int i1,i2,n,type;
double delx,dely,delz,ebond,fbond;
double rsq,r,dr,rk;
const double * const * const x = atom->x;
double * const * const f = thr->get_f();
const int * const * const bondlist = neighbor->bondlist;
const int nlocal = atom->nlocal;
for (n = nfrom; n < nto; n++) {
i1 = bondlist[n][0];
i2 = bondlist[n][1];
type = bondlist[n][2];
delx = x[i1][0] - x[i2][0];
dely = x[i1][1] - x[i2][1];
delz = x[i1][2] - x[i2][2];
domain->minimum_image(delx,dely,delz);
rsq = delx*delx + dely*dely + delz*delz;
r = sqrt(rsq);
if (r>r1[type]) continue;
dr = r - r0[type];
rk = k[type] * dr;
// force & energy
if (r > 0.0) fbond = -2.0*rk/r;
else fbond = 0.0;
if (EFLAG) ebond = k[type]*(dr*dr -(r0[type]-r1[type])*(r0[type]-r1[type]) );
// apply force to each of 2 atoms
if (NEWTON_BOND || i1 < nlocal) {
f[i1][0] += delx*fbond;
f[i1][1] += dely*fbond;
f[i1][2] += delz*fbond;
}
if (NEWTON_BOND || i2 < nlocal) {
f[i2][0] -= delx*fbond;
f[i2][1] -= dely*fbond;
f[i2][2] -= delz*fbond;
}
if (EVFLAG) ev_tally_thr(this,i1,i2,nlocal,NEWTON_BOND,
ebond,fbond,delx,dely,delz,thr);
}
}
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