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lammps/src/USER-OMP/pair_gran_hertz_history_omp.cpp
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pair_gran_hertz_history_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
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_gran_hertz_history_omp.h"
#include "fix_neigh_history.h"
#include "atom.h"
#include "comm.h"
#include "fix.h"
#include "force.h"
#include "memory.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "update.h"
#include "suffix.h"
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
PairGranHertzHistoryOMP::PairGranHertzHistoryOMP(LAMMPS *lmp) :
PairGranHertzHistory(lmp), ThrOMP(lmp, THR_PAIR)
{
suffix_flag |= Suffix::OMP;
respa_enable = 0;
}
/* ---------------------------------------------------------------------- */
void PairGranHertzHistoryOMP::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 shearupdate = (update->setupflag) ? 0 : 1;
// update rigid body info for owned & ghost atoms if using FixRigid masses
// body[i] = which body atom I is in, -1 if none
// mass_body = mass of each rigid body
if (fix_rigid && neighbor->ago == 0) {
int tmp;
int *body = (int *) fix_rigid->extract("body",tmp);
double *mass_body = (double *) fix_rigid->extract("masstotal",tmp);
if (atom->nmax > nmax) {
memory->destroy(mass_rigid);
nmax = atom->nmax;
memory->create(mass_rigid,nmax,"pair:mass_rigid");
}
int nlocal = atom->nlocal;
for (int i = 0; i < nlocal; i++)
if (body[i] >= 0) mass_rigid[i] = mass_body[body[i]];
else mass_rigid[i] = 0.0;
comm->forward_comm_pair(this);
}
#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);
thr->timer(Timer::START);
ev_setup_thr(eflag, vflag, nall, eatom, vatom, thr);
if (evflag) {
if (shearupdate) {
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 (shearupdate) {
if (force->newton_pair) eval<0,1,1>(ifrom, ito, thr);
else eval<0,1,0>(ifrom, ito, thr);
} else {
if (force->newton_pair) eval<0,0,1>(ifrom, ito, thr);
else eval<0,0,0>(ifrom, ito, thr);
}
}
thr->timer(Timer::PAIR);
reduce_thr(this, eflag, vflag, thr);
} // end of omp parallel region
}
template <int EVFLAG, int SHEARUPDATE, int NEWTON_PAIR>
void PairGranHertzHistoryOMP::eval(int iifrom, int iito, ThrData * const thr)
{
int i,j,ii,jj,jnum;
double xtmp,ytmp,ztmp,delx,dely,delz,fx,fy,fz;
double radi,radj,radsum,rsq,r,rinv,rsqinv;
double vr1,vr2,vr3,vnnr,vn1,vn2,vn3,vt1,vt2,vt3;
double wr1,wr2,wr3;
double vtr1,vtr2,vtr3,vrel;
double mi,mj,meff,damp,ccel,tor1,tor2,tor3;
double fn,fs,fs1,fs2,fs3;
double shrmag,rsht,polyhertz;
int *ilist,*jlist,*numneigh,**firstneigh;
int *touch,**firsttouch;
double *shear,*allshear,**firstshear;
const double * const * const x = atom->x;
const double * const * const v = atom->v;
const double * const * const omega = atom->omega;
const double * const radius = atom->radius;
const double * const rmass = atom->rmass;
double * const * const f = thr->get_f();
double * const * const torque = thr->get_torque();
const int * const mask = atom->mask;
const int nlocal = atom->nlocal;
double fxtmp,fytmp,fztmp;
double t1tmp,t2tmp,t3tmp;
ilist = list->ilist;
numneigh = list->numneigh;
firstneigh = list->firstneigh;
firsttouch = fix_history->firstflag;
firstshear = fix_history->firstvalue;
// 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];
radi = radius[i];
touch = firsttouch[i];
allshear = firstshear[i];
jlist = firstneigh[i];
jnum = numneigh[i];
fxtmp=fytmp=fztmp=t1tmp=t2tmp=t3tmp=0.0;
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;
radj = radius[j];
radsum = radi + radj;
if (rsq >= radsum*radsum) {
// unset non-touching neighbors
touch[jj] = 0;
shear = &allshear[3*jj];
shear[0] = 0.0;
shear[1] = 0.0;
shear[2] = 0.0;
} else {
r = sqrt(rsq);
rinv = 1.0/r;
rsqinv = 1.0/rsq;
// relative translational velocity
vr1 = v[i][0] - v[j][0];
vr2 = v[i][1] - v[j][1];
vr3 = v[i][2] - v[j][2];
// normal component
vnnr = vr1*delx + vr2*dely + vr3*delz;
vn1 = delx*vnnr * rsqinv;
vn2 = dely*vnnr * rsqinv;
vn3 = delz*vnnr * rsqinv;
// tangential component
vt1 = vr1 - vn1;
vt2 = vr2 - vn2;
vt3 = vr3 - vn3;
// relative rotational velocity
wr1 = (radi*omega[i][0] + radj*omega[j][0]) * rinv;
wr2 = (radi*omega[i][1] + radj*omega[j][1]) * rinv;
wr3 = (radi*omega[i][2] + radj*omega[j][2]) * rinv;
// meff = effective mass of pair of particles
// if I or J part of rigid body, use body mass
// if I or J is frozen, meff is other particle
mi = rmass[i];
mj = rmass[j];
if (fix_rigid) {
if (mass_rigid[i] > 0.0) mi = mass_rigid[i];
if (mass_rigid[j] > 0.0) mj = mass_rigid[j];
}
meff = mi*mj / (mi+mj);
if (mask[i] & freeze_group_bit) meff = mj;
if (mask[j] & freeze_group_bit) meff = mi;
// normal force = Hertzian contact + normal velocity damping
damp = meff*gamman*vnnr*rsqinv;
ccel = kn*(radsum-r)*rinv - damp;
polyhertz = sqrt((radsum-r)*radi*radj / radsum);
ccel *= polyhertz;
// relative velocities
vtr1 = vt1 - (delz*wr2-dely*wr3);
vtr2 = vt2 - (delx*wr3-delz*wr1);
vtr3 = vt3 - (dely*wr1-delx*wr2);
vrel = vtr1*vtr1 + vtr2*vtr2 + vtr3*vtr3;
vrel = sqrt(vrel);
// shear history effects
touch[jj] = 1;
shear = &allshear[3*jj];
if (SHEARUPDATE) {
shear[0] += vtr1*dt;
shear[1] += vtr2*dt;
shear[2] += vtr3*dt;
}
shrmag = sqrt(shear[0]*shear[0] + shear[1]*shear[1] +
shear[2]*shear[2]);
// rotate shear displacements
rsht = shear[0]*delx + shear[1]*dely + shear[2]*delz;
rsht *= rsqinv;
if (SHEARUPDATE) {
shear[0] -= rsht*delx;
shear[1] -= rsht*dely;
shear[2] -= rsht*delz;
}
// tangential forces = shear + tangential velocity damping
fs1 = -polyhertz * (kt*shear[0] + meff*gammat*vtr1);
fs2 = -polyhertz * (kt*shear[1] + meff*gammat*vtr2);
fs3 = -polyhertz * (kt*shear[2] + meff*gammat*vtr3);
// rescale frictional displacements and forces if needed
fs = sqrt(fs1*fs1 + fs2*fs2 + fs3*fs3);
fn = xmu * fabs(ccel*r);
if (fs > fn) {
if (shrmag != 0.0) {
const double fnfs = fn/fs;
const double mgkt = meff*gammat/kt;
shear[0] = fnfs * (shear[0] + mgkt*vtr1) - mgkt*vtr1;
shear[1] = fnfs * (shear[1] + mgkt*vtr2) - mgkt*vtr2;
shear[2] = fnfs * (shear[2] + mgkt*vtr3) - mgkt*vtr3;
fs1 *= fnfs;
fs2 *= fnfs;
fs3 *= fnfs;
} else fs1 = fs2 = fs3 = 0.0;
}
// forces & torques
fx = delx*ccel + fs1;
fy = dely*ccel + fs2;
fz = delz*ccel + fs3;
fxtmp += fx;
fytmp += fy;
fztmp += fz;
tor1 = rinv * (dely*fs3 - delz*fs2);
tor2 = rinv * (delz*fs1 - delx*fs3);
tor3 = rinv * (delx*fs2 - dely*fs1);
t1tmp -= radi*tor1;
t2tmp -= radi*tor2;
t3tmp -= radi*tor3;
if (NEWTON_PAIR || j < nlocal) {
f[j][0] -= fx;
f[j][1] -= fy;
f[j][2] -= fz;
torque[j][0] -= radj*tor1;
torque[j][1] -= radj*tor2;
torque[j][2] -= radj*tor3;
}
if (EVFLAG) ev_tally_xyz_thr(this,i,j,nlocal,NEWTON_PAIR,
0.0,0.0,fx,fy,fz,delx,dely,delz,thr);
}
}
f[i][0] += fxtmp;
f[i][1] += fytmp;
f[i][2] += fztmp;
torque[i][0] += t1tmp;
torque[i][1] += t2tmp;
torque[i][2] += t3tmp;
}
}
/* ---------------------------------------------------------------------- */
double PairGranHertzHistoryOMP::memory_usage()
{
double bytes = memory_usage_thr();
bytes += PairGranHertzHistory::memory_usage();
return bytes;
}
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