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lammps/src/USER-OMP/fix_shear_history_omp.cpp
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fix_shear_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
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 "string.h"
#include "stdio.h"
#include "fix_shear_history_omp.h"
#include "atom.h"
#include "comm.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "force.h"
#include "pair.h"
#include "update.h"
#include "modify.h"
#include "error.h"
#if defined(_OPENMP)
#include <omp.h>
#endif
using namespace LAMMPS_NS;
using namespace FixConst;
/* ----------------------------------------------------------------------
copy shear partner info from neighbor lists to per-atom arrays
so it can be exchanged with those atoms
------------------------------------------------------------------------- */
void FixShearHistoryOMP::pre_exchange()
{
const int nthreads = comm->nthreads;
maxtouch = 0;
#if defined(_OPENMP)
#pragma omp parallel default(none)
#endif
{
#if defined(_OPENMP)
const int tid = omp_get_thread_num();
#else
const int tid = 0;
#endif
int i,j,ii,jj,m,n,inum,jnum;
int *ilist,*jlist,*numneigh,**firstneigh;
int *touch,**firsttouch;
double *shear,*allshear,**firstshear;
MyPage <tagint> &ipg = ipage[tid];
MyPage <double[3]> &dpg = dpage[tid];
ipg.reset();
dpg.reset();
// 1st loop over neighbor list
// calculate nparter for each owned atom
tagint *tag = atom->tag;
NeighList *list = pair->list;
inum = list->inum;
ilist = list->ilist;
numneigh = list->numneigh;
firstneigh = list->firstneigh;
firsttouch = list->listgranhistory->firstneigh;
firstshear = list->listgranhistory->firstdouble;
int nlocal_neigh = 0;
if (inum) nlocal_neigh = ilist[inum-1] + 1;
// each thread works on a fixed chunk of local and ghost atoms.
const int ldelta = 1 + nlocal_neigh/nthreads;
const int lfrom = tid*ldelta;
const int lmax = lfrom +ldelta;
const int lto = (lmax > nlocal_neigh) ? nlocal_neigh : lmax;
// zero npartners for all current atoms and
// clear page data structures for this thread
for (i = lfrom; i < lto; i++) npartner[i] = 0;
for (ii = 0; ii < inum; ii++) {
i = ilist[ii];
jlist = firstneigh[i];
jnum = numneigh[i];
touch = firsttouch[i];
for (jj = 0; jj < jnum; jj++) {
if (touch[jj]) {
if ((i >= lfrom) && (i < lto))
npartner[i]++;
j = jlist[jj];
j &= NEIGHMASK;
if ((j >= lfrom) && (j < lto))
npartner[j]++;
}
}
}
// get page chunks to store atom IDs and shear history for my atoms
for (ii = 0; ii < inum; ii++) {
i = ilist[ii];
if ((i >= lfrom) && (i < lto)) {
n = npartner[i];
partner[i] = ipg.get(n);
shearpartner[i] = dpg.get(n);
if (partner[i] == NULL || shearpartner[i] == NULL)
error->one(FLERR,"Shear history overflow, boost neigh_modify one");
}
}
// 2nd loop over neighbor list
// store atom IDs and shear history for my atoms
// re-zero npartner to use as counter for all my atoms
for (i = lfrom; i < lto; i++) npartner[i] = 0;
for (ii = 0; ii < inum; ii++) {
i = ilist[ii];
jlist = firstneigh[i];
allshear = firstshear[i];
jnum = numneigh[i];
touch = firsttouch[i];
for (jj = 0; jj < jnum; jj++) {
if (touch[jj]) {
shear = &allshear[3*jj];
j = jlist[jj];
j &= NEIGHMASK;
if ((i >= lfrom) && (i < lto)) {
m = npartner[i];
partner[i][m] = tag[j];
shearpartner[i][m][0] = shear[0];
shearpartner[i][m][1] = shear[1];
shearpartner[i][m][2] = shear[2];
npartner[i]++;
}
if ((j >= lfrom) && (j < lto)) {
m = npartner[j];
partner[j][m] = tag[i];
shearpartner[j][m][0] = -shear[0];
shearpartner[j][m][1] = -shear[1];
shearpartner[j][m][2] = -shear[2];
npartner[j]++;
}
}
}
}
// set maxtouch = max # of partners of any owned atom
maxtouch = m = 0;
for (i = lfrom; i < lto; i++)
m = MAX(m,npartner[i]);
#if defined(_OPENMP)
#pragma omp critical
#endif
maxtouch = MAX(m,maxtouch);
}
}
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