implement vashishta/table/omp in USER-OMP

  void settings(int, char **);

  double memory_usage();

 private:

 protected:

  int ntable;

  double deltaR2;

  double oneOverDeltaR2;

/* ----------------------------------------------------------------------

   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_vashishta_table_omp.h"

#include "atom.h"

#include "comm.h"

#include "force.h"

#include "memory.h"

#include "neighbor.h"

#include "neigh_list.h"

#include "suffix.h"

using namespace LAMMPS_NS;

/* ---------------------------------------------------------------------- */

PairVashishtaTableOMP::PairVashishtaTableOMP(LAMMPS *lmp) :

  PairVashishtaTable(lmp), ThrOMP(lmp, THR_PAIR)

{

  suffix_flag |= Suffix::OMP;

  respa_enable = 0;

}

/* ---------------------------------------------------------------------- */

void PairVashishtaTableOMP::compute(int eflag, int vflag)

{

  if (eflag || vflag) {

    ev_setup(eflag,vflag);

  } else evflag = vflag_fdotr = 0;

  // reallocate 3-body neighbor list if necessary

  // NOTE: using 1000 is inefficient

  //       could make this a LAMMPS paged neighbor list

  if (atom->nlocal > neigh3BodyMax) {

    neigh3BodyMax = atom->nmax;

    memory->destroy(neigh3BodyCount);

    memory->destroy(neigh3Body);

    memory->create(neigh3BodyCount,neigh3BodyMax,

                   "pair:vashishta:neigh3BodyCount");

    memory->create(neigh3Body,neigh3BodyMax,1000,

                   "pair:vashishta:neigh3Body");

  }

  const int nall = atom->nlocal + atom->nghost;

  const int nthreads = comm->nthreads;

  const int inum = list->inum;

#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 (eflag) {

        eval<1,1>(ifrom, ito, thr);

      } else {

        eval<1,0>(ifrom, ito, thr);

      }

    } else eval<0,0>(ifrom, ito, thr);

    thr->timer(Timer::PAIR);

    reduce_thr(this, eflag, vflag, thr);

  } // end of omp parallel region

}

template <int EVFLAG, int EFLAG>

void PairVashishtaTableOMP::eval(int iifrom, int iito, ThrData * const thr)

{

  int i,j,k,ii,jj,kk,jnum,jnumm1;

  tagint itag,jtag;

  int itype,jtype,ktype,ijparam,ikparam,ijkparam;

  double xtmp,ytmp,ztmp,delx,dely,delz,evdwl,fpair;

  double rsq,rsq1,rsq2;

  double delr1[3],delr2[3],fj[3],fk[3];

  int *ilist,*jlist,*numneigh,**firstneigh;

  evdwl = 0.0;

  const dbl3_t * _noalias const x = (dbl3_t *) atom->x[0];

  dbl3_t * _noalias const f = (dbl3_t *) thr->get_f()[0];

  const tagint * _noalias const tag = atom->tag;

  const int * _noalias const type = atom->type;

  const int nlocal = atom->nlocal;

  ilist = list->ilist;

  numneigh = list->numneigh;

  firstneigh = list->firstneigh;

  double fxtmp,fytmp,fztmp;

  // loop over full neighbor list of my atoms

  for (ii = iifrom; ii < iito; ++ii) {

    i = ilist[ii];

    itag = tag[i];

    itype = map[type[i]];

    xtmp = x[i].x;

    ytmp = x[i].y;

    ztmp = x[i].z;

    fxtmp = fytmp = fztmp = 0.0;

    // reset the 3-body neighbor list

    neigh3BodyCount[i] = 0;

    // two-body interactions, skip half of them

    jlist = firstneigh[i];

    jnum = numneigh[i];

    for (jj = 0; jj < jnum; jj++) {

      j = jlist[jj];

      j &= NEIGHMASK;

      jtag = tag[j];

      jtype = map[type[j]];

      delx = xtmp - x[j].x;

      dely = ytmp - x[j].y;

      delz = ztmp - x[j].z;

      rsq = delx*delx + dely*dely + delz*delz;

      ijparam = elem2param[itype][jtype][jtype];

      if (rsq <= params[ijparam].cutsq2) {

        neigh3Body[i][neigh3BodyCount[i]] = j;

        neigh3BodyCount[i]++;

      }

      if (rsq >= params[ijparam].cutsq) continue;

      if (itag > jtag) {

        if ((itag+jtag) % 2 == 0) continue;

      } else if (itag < jtag) {

        if ((itag+jtag) % 2 == 1) continue;

      } else {

        if (x[j].z < ztmp) continue;

        if (x[j].z == ztmp && x[j].y < ytmp) continue;

        if (x[j].z == ztmp && x[j].y == ytmp && x[j].x < xtmp) continue;

      }

      twobody_table(params[ijparam],rsq,fpair,EFLAG,evdwl);

      fxtmp += delx*fpair;

      fytmp += dely*fpair;

      fztmp += delz*fpair;

      f[j].x -= delx*fpair;

      f[j].y -= dely*fpair;

      f[j].z -= delz*fpair;

      if (EVFLAG) ev_tally_thr(this,i,j,nlocal,/* newton_pair */ 1,

                               evdwl,0.0,fpair,delx,dely,delz,thr);

    }

    jlist = neigh3Body[i];

    jnum = neigh3BodyCount[i];

    jnumm1 = jnum - 1;

    for (jj = 0; jj < jnumm1; jj++) {

      j = jlist[jj];

      j &= NEIGHMASK;

      jtype = map[type[j]];

      ijparam = elem2param[itype][jtype][jtype];

      delr1[0] = x[j].x - xtmp;

      delr1[1] = x[j].y - ytmp;

      delr1[2] = x[j].z - ztmp;

      rsq1 = delr1[0]*delr1[0] + delr1[1]*delr1[1] + delr1[2]*delr1[2];

      if (rsq1 >= params[ijparam].cutsq2) continue;

      double fjxtmp,fjytmp,fjztmp;

      fjxtmp = fjytmp = fjztmp = 0.0;

      for (kk = jj+1; kk < jnum; kk++) {

        k = jlist[kk];

        k &= NEIGHMASK;

        ktype = map[type[k]];

        ikparam = elem2param[itype][ktype][ktype];

        ijkparam = elem2param[itype][jtype][ktype];

        delr2[0] = x[k].x - xtmp;

        delr2[1] = x[k].y - ytmp;

        delr2[2] = x[k].z - ztmp;

        rsq2 = delr2[0]*delr2[0] + delr2[1]*delr2[1] + delr2[2]*delr2[2];

        if (rsq2 >= params[ikparam].cutsq2) continue;

        threebody(&params[ijparam],&params[ikparam],&params[ijkparam],

                  rsq1,rsq2,delr1,delr2,fj,fk,EFLAG,evdwl);

        fxtmp -= fj[0] + fk[0];

        fytmp -= fj[1] + fk[1];

        fztmp -= fj[2] + fk[2];

        fjxtmp += fj[0];

        fjytmp += fj[1];

        fjztmp += fj[2];

        f[k].x += fk[0];

        f[k].y += fk[1];

        f[k].z += fk[2];

        if (EVFLAG) ev_tally3_thr(this,i,j,k,evdwl,0.0,fj,fk,delr1,delr2,thr);

      }

      f[j].x += fjxtmp;

      f[j].y += fjytmp;

      f[j].z += fjztmp;

    }

    f[i].x += fxtmp;

    f[i].y += fytmp;

    f[i].z += fztmp;

  }

}

/* ---------------------------------------------------------------------- */

double PairVashishtaTableOMP::memory_usage()

{

  double bytes = memory_usage_thr();

  bytes += PairVashishtaTable::memory_usage();

  return bytes;

}

/* -*- c++ -*- ----------------------------------------------------------

   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)

------------------------------------------------------------------------- */

#ifdef PAIR_CLASS

PairStyle(vashishta/table/omp,PairVashishtaTableOMP)

#else

#ifndef LMP_PAIR_VASHISHTA_TABLE_OMP_H

#define LMP_PAIR_VASHISHTA_TABLE_OMP_H

#include "pair_vashishta_table.h"

#include "thr_omp.h"

namespace LAMMPS_NS {

class PairVashishtaTableOMP : public PairVashishtaTable, public ThrOMP {

 public:

  PairVashishtaTableOMP(class LAMMPS *);

  virtual void compute(int, int);

  virtual double memory_usage();

 private:

  template <int EVFLAG, int EFLAG>

  void eval(int ifrom, int ito, ThrData * const thr);

};

}

#endif

#endif