750 lines
22 KiB
C++
Executable File
750 lines
22 KiB
C++
Executable File
/* ----------------------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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http://lammps.sandia.gov, Sandia National Laboratories
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Steve Plimpton, sjplimp@sandia.gov
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Copyright (2003) Sandia Corporation. Under the terms of Contract
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DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
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certain rights in this software. This software is distributed under
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the GNU General Public License.
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See the README file in the top-level LAMMPS directory.
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------------------------------------------------------------------------- */
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/* ----------------------------------------------------------------------
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Contributing author: Yongnan Xiong (HNU), xyn@hnu.edu.cn
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Aidan Thompson (SNL)
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Anders Hafreager (UiO), andershaf@gmail.com
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------------------------------------------------------------------------- */
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "pair_vashishta.h"
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#include "atom.h"
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#include "neighbor.h"
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#include "neigh_request.h"
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#include "force.h"
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#include "comm.h"
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#include "memory.h"
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#include "neighbor.h"
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#include "neigh_list.h"
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#include "memory.h"
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#include "error.h"
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using namespace LAMMPS_NS;
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#define MAXLINE 1024
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#define DELTA 4
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/* ---------------------------------------------------------------------- */
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PairVashishta::PairVashishta(LAMMPS *lmp) : Pair(lmp)
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{
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single_enable = 0;
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restartinfo = 0;
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one_coeff = 1;
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manybody_flag = 1;
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nelements = 0;
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elements = NULL;
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nparams = maxparam = 0;
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params = NULL;
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elem2param = NULL;
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map = NULL;
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neigh3BodyMax = 0;
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neigh3BodyCount = NULL;
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neigh3Body = NULL;
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useTable = false;
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nTablebits = 12;
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forceTable = NULL;
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potentialTable = NULL;
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}
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/* ----------------------------------------------------------------------
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check if allocated, since class can be destructed when incomplete
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------------------------------------------------------------------------- */
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PairVashishta::~PairVashishta()
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{
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if (elements)
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for (int i = 0; i < nelements; i++) delete [] elements[i];
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delete [] elements;
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memory->destroy(params);
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memory->destroy(elem2param);
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memory->destroy(forceTable);
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memory->destroy(potentialTable);
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memory->destroy(neigh3BodyCount);
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memory->destroy(neigh3Body);
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if (allocated) {
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memory->destroy(setflag);
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memory->destroy(cutsq);
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delete [] map;
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}
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}
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void PairVashishta::modify_params(int narg, char **arg)
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{
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if (narg == 0) error->all(FLERR,"Illegal pair_modify command");
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int iarg = 0;
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while (iarg < narg) {
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if (strcmp(arg[iarg],"table") == 0) {
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if (iarg+2 > narg) error->all(FLERR,"Illegal pair_modify command");
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nTablebits = force->inumeric(FLERR,arg[iarg+1]);
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if (nTablebits > sizeof(float)*CHAR_BIT) {
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error->all(FLERR,"Too many total bits for bitmapped lookup table");
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}
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if(nTablebits == 0) {
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useTable = false;
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} else {
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useTable = true;
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}
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iarg += 2;
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} else if (strcmp(arg[iarg],"tabinner") == 0) {
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if (iarg+2 > narg) error->all(FLERR,"Illegal pair_modify command");
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tabinner = force->numeric(FLERR,arg[iarg+1]);
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iarg += 2;
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}
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}
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createTable();
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}
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void PairVashishta::validateNeigh3Body() {
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if (atom->nlocal > neigh3BodyMax) {
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neigh3BodyMax = atom->nmax;
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memory->destroy(neigh3BodyCount);
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memory->destroy(neigh3Body);
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memory->create(neigh3BodyCount,neigh3BodyMax, "pair:vashishta:neigh3BodyCount");
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memory->create(neigh3Body,neigh3BodyMax, 1000, "pair:vashishta:neigh3Body"); // TODO: pick this number more wisely?
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}
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}
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void PairVashishta::createTable()
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{
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int ntypes = atom->ntypes+1;
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tabinnersq = tabinner*tabinner;
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int ntable = 1;
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for (int i = 0; i < nTablebits; i++) ntable *= 2;
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deltaR2 = (cutmax*cutmax - tabinnersq) / (ntable-1);
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oneOverDeltaR2 = 1.0/deltaR2;
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memory->destroy(forceTable);
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memory->destroy(potentialTable);
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memory->create(forceTable,ntypes,ntypes,ntable+1,"pair:vashishta:forceTable");
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memory->create(potentialTable,ntypes,ntypes,ntable+1,"pair:vashishta:potentialTable");
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for (int ii = 0; ii < ntypes; ii++) {
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int i = map[ii];
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for (int jj = 0; jj < ntypes; jj++) {
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int j = map[jj];
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if (i < 0 || j < 0 || ii == 0 || jj == 0) {
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for(int tableIndex=0; tableIndex<=ntable; tableIndex++) {
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forceTable[ii][jj][tableIndex] = 0;
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potentialTable[ii][jj][tableIndex] = 0;
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}
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} else {
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int ijparam = elem2param[i][j][j];
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for(int tableIndex=0; tableIndex<=ntable; tableIndex++) {
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double rsq = tabinnersq + tableIndex*deltaR2;
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double fpair, eng;
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twobody(¶ms[ijparam], rsq, fpair, 1, eng, false /* Don't ask for tabulated since we are generating it now*/ );
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forceTable[ii][jj][tableIndex] = fpair;
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potentialTable[ii][jj][tableIndex] = eng;
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}
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}
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}
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}
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}
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/* ---------------------------------------------------------------------- */
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void PairVashishta::compute(int eflag, int vflag)
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{
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validateNeigh3Body();
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int i,j,k,ii,jj,kk,inum,jnum,jnumm1;
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int itype,jtype,ktype,ijparam,ikparam,ijkparam;
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tagint itag,jtag;
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double xtmp,ytmp,ztmp,delx,dely,delz,evdwl,fpair;
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double rsq,rsq1,rsq2;
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double delr1[3],delr2[3],fj[3],fk[3];
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int *ilist,*jlist,*numneigh,**firstneigh;
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evdwl = 0.0;
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if (eflag || vflag) ev_setup(eflag,vflag);
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else evflag = vflag_fdotr = 0;
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double **x = atom->x;
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double **f = atom->f;
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tagint *tag = atom->tag;
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int *type = atom->type;
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int nlocal = atom->nlocal;
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int newton_pair = force->newton_pair;
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inum = list->inum;
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ilist = list->ilist;
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numneigh = list->numneigh;
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firstneigh = list->firstneigh;
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// loop over full neighbor list of my atoms
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for (ii = 0; ii < inum; ii++) {
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i = ilist[ii];
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itag = tag[i];
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itype = map[type[i]];
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xtmp = x[i][0];
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ytmp = x[i][1];
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ztmp = x[i][2];
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neigh3BodyCount[i] = 0; // Reset the 3-body neighbor list
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// two-body interactions, skip half of them
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jlist = firstneigh[i];
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jnum = numneigh[i];
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for (jj = 0; jj < jnum; jj++) {
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j = jlist[jj];
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j &= NEIGHMASK;
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jtag = tag[j];
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jtype = map[type[j]];
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delx = xtmp - x[j][0];
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dely = ytmp - x[j][1];
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delz = ztmp - x[j][2];
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rsq = delx*delx + dely*dely + delz*delz;
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ijparam = elem2param[itype][jtype][jtype];
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if (rsq <= params[ijparam].cutsq2) {
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neigh3Body[i][neigh3BodyCount[i]] = j;
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neigh3BodyCount[i]++;
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}
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if (rsq > params[ijparam].cutsq) continue;
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if (itag > jtag) {
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if ((itag+jtag) % 2 == 0) continue;
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} else if (itag < jtag) {
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if ((itag+jtag) % 2 == 1) continue;
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} else {
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if (x[j][2] < ztmp) continue;
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if (x[j][2] == ztmp && x[j][1] < ytmp) continue;
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if (x[j][2] == ztmp && x[j][1] == ytmp && x[j][0] < xtmp) continue;
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}
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twobody(¶ms[ijparam],rsq,fpair,eflag,evdwl, useTable);
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f[i][0] += delx*fpair;
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f[i][1] += dely*fpair;
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f[i][2] += delz*fpair;
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f[j][0] -= delx*fpair;
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f[j][1] -= dely*fpair;
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f[j][2] -= delz*fpair;
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if (evflag) ev_tally(i,j,nlocal,newton_pair,
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evdwl,0.0,fpair,delx,dely,delz);
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}
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jlist = neigh3Body[i];
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jnum = neigh3BodyCount[i];
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jnumm1 = jnum - 1;
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for (jj = 0; jj < jnumm1; jj++) {
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j = jlist[jj];
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j &= NEIGHMASK;
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jtype = map[type[j]];
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ijparam = elem2param[itype][jtype][jtype];
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delr1[0] = x[j][0] - xtmp;
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delr1[1] = x[j][1] - ytmp;
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delr1[2] = x[j][2] - ztmp;
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rsq1 = delr1[0]*delr1[0] + delr1[1]*delr1[1] + delr1[2]*delr1[2];
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if (rsq1 >= params[ijparam].cutsq2) continue;
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for (kk = jj+1; kk < jnum; kk++) {
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k = jlist[kk];
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k &= NEIGHMASK;
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ktype = map[type[k]];
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ikparam = elem2param[itype][ktype][ktype];
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ijkparam = elem2param[itype][jtype][ktype];
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delr2[0] = x[k][0] - xtmp;
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delr2[1] = x[k][1] - ytmp;
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delr2[2] = x[k][2] - ztmp;
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rsq2 = delr2[0]*delr2[0] + delr2[1]*delr2[1] + delr2[2]*delr2[2];
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if (rsq2 >= params[ikparam].cutsq2) continue;
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threebody(¶ms[ijparam],¶ms[ikparam],¶ms[ijkparam],
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rsq1,rsq2,delr1,delr2,fj,fk,eflag,evdwl);
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f[i][0] -= fj[0] + fk[0];
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f[i][1] -= fj[1] + fk[1];
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f[i][2] -= fj[2] + fk[2];
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f[j][0] += fj[0];
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f[j][1] += fj[1];
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f[j][2] += fj[2];
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f[k][0] += fk[0];
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f[k][1] += fk[1];
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f[k][2] += fk[2];
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if (evflag) ev_tally3(i,j,k,evdwl,0.0,fj,fk,delr1,delr2);
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}
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}
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}
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if (vflag_fdotr) virial_fdotr_compute();
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}
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/* ---------------------------------------------------------------------- */
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void PairVashishta::allocate()
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{
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allocated = 1;
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int n = atom->ntypes;
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memory->create(setflag,n+1,n+1,"pair:setflag");
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memory->create(cutsq,n+1,n+1,"pair:cutsq");
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map = new int[n+1];
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}
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/* ----------------------------------------------------------------------
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global settings
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------------------------------------------------------------------------- */
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void PairVashishta::settings(int narg, char **arg)
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{
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if (narg != 0) error->all(FLERR,"Illegal pair_style command");
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}
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/* ----------------------------------------------------------------------
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set coeffs for one or more type pairs
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------------------------------------------------------------------------- */
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void PairVashishta::coeff(int narg, char **arg)
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{
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int i,j,n;
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if (!allocated) allocate();
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if (narg != 3 + atom->ntypes)
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error->all(FLERR,"Incorrect args for pair coefficients");
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// insure I,J args are * *
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if (strcmp(arg[0],"*") != 0 || strcmp(arg[1],"*") != 0)
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error->all(FLERR,"Incorrect args for pair coefficients");
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// read args that map atom types to elements in potential file
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// map[i] = which element the Ith atom type is, -1 if NULL
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// nelements = # of unique elements
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// elements = list of element names
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if (elements) {
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for (i = 0; i < nelements; i++) delete [] elements[i];
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delete [] elements;
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}
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elements = new char*[atom->ntypes];
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for (i = 0; i < atom->ntypes; i++) elements[i] = NULL;
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nelements = 0;
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for (i = 3; i < narg; i++) {
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if (strcmp(arg[i],"NULL") == 0) {
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map[i-2] = -1;
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continue;
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}
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for (j = 0; j < nelements; j++)
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if (strcmp(arg[i],elements[j]) == 0) break;
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map[i-2] = j;
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if (j == nelements) {
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n = strlen(arg[i]) + 1;
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elements[j] = new char[n];
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strcpy(elements[j],arg[i]);
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nelements++;
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}
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}
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// read potential file and initialize potential parameters
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read_file(arg[2]);
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setup_params();
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// clear setflag since coeff() called once with I,J = * *
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n = atom->ntypes;
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for (int i = 1; i <= n; i++)
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for (int j = i; j <= n; j++)
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setflag[i][j] = 0;
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// set setflag i,j for type pairs where both are mapped to elements
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int count = 0;
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for (int i = 1; i <= n; i++)
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for (int j = i; j <= n; j++)
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if (map[i] >= 0 && map[j] >= 0) {
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setflag[i][j] = 1;
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count++;
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}
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if (count == 0) error->all(FLERR,"Incorrect args for pair coefficients");
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}
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/* ----------------------------------------------------------------------
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init specific to this pair style
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------------------------------------------------------------------------- */
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void PairVashishta::init_style()
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{
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if (atom->tag_enable == 0)
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error->all(FLERR,"Pair style Vashishta requires atom IDs");
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if (force->newton_pair == 0)
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error->all(FLERR,"Pair style Vashishta requires newton pair on");
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// need a full neighbor list
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int irequest = neighbor->request(this);
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neighbor->requests[irequest]->half = 0;
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neighbor->requests[irequest]->full = 1;
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}
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/* ----------------------------------------------------------------------
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init for one type pair i,j and corresponding j,i
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------------------------------------------------------------------------- */
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double PairVashishta::init_one(int i, int j)
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{
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if (setflag[i][j] == 0) error->all(FLERR,"All pair coeffs are not set");
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return cutmax;
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}
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/* ---------------------------------------------------------------------- */
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void PairVashishta::read_file(char *file)
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{
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int params_per_line = 17;
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char **words = new char*[params_per_line+1];
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memory->sfree(params);
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params = NULL;
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nparams = maxparam = 0;
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// open file on proc 0
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FILE *fp;
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if (comm->me == 0) {
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fp = force->open_potential(file);
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if (fp == NULL) {
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char str[128];
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sprintf(str,"Cannot open Vashishta potential file %s",file);
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error->one(FLERR,str);
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}
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}
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// read each set of params from potential file
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// one set of params can span multiple lines
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// store params if all 3 element tags are in element list
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int n,nwords,ielement,jelement,kelement;
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char line[MAXLINE],*ptr;
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int eof = 0;
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while (1) {
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if (comm->me == 0) {
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ptr = fgets(line,MAXLINE,fp);
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if (ptr == NULL) {
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eof = 1;
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fclose(fp);
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} else n = strlen(line) + 1;
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}
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MPI_Bcast(&eof,1,MPI_INT,0,world);
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if (eof) break;
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MPI_Bcast(&n,1,MPI_INT,0,world);
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MPI_Bcast(line,n,MPI_CHAR,0,world);
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// strip comment, skip line if blank
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if ((ptr = strchr(line,'#'))) *ptr = '\0';
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nwords = atom->count_words(line);
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if (nwords == 0) continue;
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// concatenate additional lines until have params_per_line words
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while (nwords < params_per_line) {
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n = strlen(line);
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if (comm->me == 0) {
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ptr = fgets(&line[n],MAXLINE-n,fp);
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if (ptr == NULL) {
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eof = 1;
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fclose(fp);
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} else n = strlen(line) + 1;
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}
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MPI_Bcast(&eof,1,MPI_INT,0,world);
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if (eof) break;
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MPI_Bcast(&n,1,MPI_INT,0,world);
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MPI_Bcast(line,n,MPI_CHAR,0,world);
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if ((ptr = strchr(line,'#'))) *ptr = '\0';
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nwords = atom->count_words(line);
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}
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if (nwords != params_per_line)
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error->all(FLERR,"Incorrect format in Vashishta potential file");
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// words = ptrs to all words in line
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nwords = 0;
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words[nwords++] = strtok(line," \t\n\r\f");
|
|
while ((words[nwords++] = strtok(NULL," \t\n\r\f"))) continue;
|
|
|
|
// ielement,jelement,kelement = 1st args
|
|
// if all 3 args are in element list, then parse this line
|
|
// else skip to next entry in file
|
|
|
|
for (ielement = 0; ielement < nelements; ielement++)
|
|
if (strcmp(words[0],elements[ielement]) == 0) break;
|
|
if (ielement == nelements) continue;
|
|
for (jelement = 0; jelement < nelements; jelement++)
|
|
if (strcmp(words[1],elements[jelement]) == 0) break;
|
|
if (jelement == nelements) continue;
|
|
for (kelement = 0; kelement < nelements; kelement++)
|
|
if (strcmp(words[2],elements[kelement]) == 0) break;
|
|
if (kelement == nelements) continue;
|
|
|
|
// load up parameter settings and error check their values
|
|
|
|
if (nparams == maxparam) {
|
|
maxparam += DELTA;
|
|
params = (Param *) memory->srealloc(params,maxparam*sizeof(Param),
|
|
"pair:params");
|
|
}
|
|
|
|
params[nparams].ielement = ielement;
|
|
params[nparams].jelement = jelement;
|
|
params[nparams].kelement = kelement;
|
|
params[nparams].bigh = atof(words[3]);
|
|
params[nparams].eta = atof(words[4]);
|
|
params[nparams].zi = atof(words[5]);
|
|
params[nparams].zj = atof(words[6]);
|
|
params[nparams].lambda1 = atof(words[7]);
|
|
params[nparams].bigd = atof(words[8]);
|
|
params[nparams].lambda4 = atof(words[9]);
|
|
params[nparams].bigw = atof(words[10]);
|
|
params[nparams].cut = atof(words[11]);
|
|
params[nparams].bigb = atof(words[12]);
|
|
params[nparams].gamma = atof(words[13]);
|
|
params[nparams].r0 = atof(words[14]);
|
|
params[nparams].bigc = atof(words[15]);
|
|
params[nparams].costheta = atof(words[16]);
|
|
|
|
if (params[nparams].bigb < 0.0 || params[nparams].gamma < 0.0 ||
|
|
params[nparams].r0 < 0.0 || params[nparams].bigc < 0.0 ||
|
|
params[nparams].bigh < 0.0 || params[nparams].eta < 0.0 ||
|
|
params[nparams].lambda1 < 0.0 || params[nparams].bigd < 0.0 ||
|
|
params[nparams].lambda4 < 0.0 || params[nparams].bigw < 0.0 ||
|
|
params[nparams].cut < 0.0)
|
|
error->all(FLERR,"Illegal Vashishta parameter");
|
|
|
|
nparams++;
|
|
}
|
|
|
|
delete [] words;
|
|
}
|
|
|
|
/* ---------------------------------------------------------------------- */
|
|
|
|
void PairVashishta::setup_params()
|
|
{
|
|
int i,j,k,m,n;
|
|
|
|
// set elem2param for all triplet combinations
|
|
// must be a single exact match to lines read from file
|
|
// do not allow for ACB in place of ABC
|
|
|
|
memory->destroy(elem2param);
|
|
memory->create(elem2param,nelements,nelements,nelements,"pair:elem2param");
|
|
|
|
for (i = 0; i < nelements; i++)
|
|
for (j = 0; j < nelements; j++)
|
|
for (k = 0; k < nelements; k++) {
|
|
n = -1;
|
|
for (m = 0; m < nparams; m++) {
|
|
if (i == params[m].ielement && j == params[m].jelement &&
|
|
k == params[m].kelement) {
|
|
if (n >= 0) error->all(FLERR,"Potential file has duplicate entry");
|
|
n = m;
|
|
}
|
|
}
|
|
if (n < 0) error->all(FLERR,"Potential file is missing an entry");
|
|
elem2param[i][j][k] = n;
|
|
}
|
|
|
|
// compute parameter values derived from inputs
|
|
|
|
// set cutsq using shortcut to reduce neighbor list for accelerated
|
|
// calculations. cut must remain unchanged as it is a potential parameter
|
|
double tmp_par;
|
|
|
|
for (m = 0; m < nparams; m++) {
|
|
params[m].cutsq = params[m].cut * params[m].cut;
|
|
params[m].cutsq2 = params[m].r0 * params[m].r0;
|
|
|
|
tmp_par = params[m].lambda1;
|
|
params[m].lam1inv = (tmp_par == 0.0) ? 0.0 : 1.0/tmp_par;
|
|
tmp_par = params[m].lambda4;
|
|
params[m].lam4inv = (tmp_par == 0.0) ? 0.0 : 1.0/tmp_par;
|
|
params[m].zizj = params[m].zi*params[m].zj * force->qqr2e;
|
|
// note that bigd does not have 1/2 factor
|
|
params[m].mbigd = params[m].bigd;
|
|
params[m].heta = params[m].bigh*params[m].eta;
|
|
params[m].big2b = 2.0*params[m].bigb;
|
|
params[m].big6w = 6.0*params[m].bigw;
|
|
|
|
tmp_par = params[m].cut;
|
|
params[m].rcinv = (tmp_par == 0.0) ? 0.0 : 1.0/tmp_par;
|
|
params[m].rc2inv = params[m].rcinv*params[m].rcinv;
|
|
params[m].rc4inv = params[m].rc2inv*params[m].rc2inv;
|
|
params[m].rc6inv = params[m].rc2inv*params[m].rc4inv;
|
|
params[m].rceta = pow(params[m].rcinv,params[m].eta);
|
|
params[m].lam1rc = params[m].cut*params[m].lam1inv;
|
|
params[m].lam4rc = params[m].cut*params[m].lam4inv;
|
|
params[m].vrcc2 = params[m].zizj*params[m].rcinv *
|
|
exp(-params[m].lam1rc);
|
|
params[m].vrcc3 = params[m].mbigd*params[m].rc4inv *
|
|
exp(-params[m].lam4rc);
|
|
params[m].vrc = params[m].bigh*params[m].rceta +
|
|
params[m].vrcc2 - params[m].vrcc3 -
|
|
params[m].bigw*params[m].rc6inv;
|
|
|
|
params[m].dvrc =
|
|
params[m].vrcc3 * (4.0*params[m].rcinv+params[m].lam4inv)
|
|
+ params[m].big6w * params[m].rc6inv * params[m].rcinv
|
|
- params[m].heta * params[m].rceta*params[m].rcinv
|
|
- params[m].vrcc2 * (params[m].rcinv+params[m].lam1inv);
|
|
params[m].c0 = params[m].cut*params[m].dvrc - params[m].vrc;
|
|
}
|
|
|
|
// set cutmax to max of all params
|
|
|
|
cutmax = 0.0;
|
|
for (m = 0; m < nparams; m++) {
|
|
if (params[m].cut > cutmax) cutmax = params[m].cut;
|
|
if (params[m].r0 > cutmax) cutmax = params[m].r0;
|
|
}
|
|
|
|
createTable();
|
|
}
|
|
|
|
/* ---------------------------------------------------------------------- */
|
|
|
|
void PairVashishta::twobody(Param *param, double rsq, double &fforce,
|
|
int eflag, double &eng, bool tabulated)
|
|
{
|
|
if(tabulated) {
|
|
if (rsq < tabinnersq) {
|
|
sprintf(estr,"Pair distance < table inner cutoff: "
|
|
"ijtype %d %d dist %g",param->ielement+1,param->jelement+1,sqrt(rsq));
|
|
error->one(FLERR,estr);
|
|
}
|
|
|
|
int tableIndex = (rsq - tabinnersq)*oneOverDeltaR2;
|
|
double fraction = (rsq - tabinnersq)*oneOverDeltaR2 - tableIndex; // double - int will only keep the 0.xxxx part
|
|
|
|
double force0 = forceTable[param->ielement+1][param->jelement+1][tableIndex];
|
|
double force1 = forceTable[param->ielement+1][param->jelement+1][tableIndex+1];
|
|
fforce = (1.0 - fraction)*force0 + fraction*force1; // force is linearly interpolated between the two values
|
|
if(evflag) {
|
|
double energy0 = potentialTable[param->ielement+1][param->jelement+1][tableIndex];
|
|
double energy1 = potentialTable[param->ielement+1][param->jelement+1][tableIndex+1];
|
|
eng = (1.0 - fraction)*energy0 + fraction*energy1;
|
|
}
|
|
} else {
|
|
double r,rinvsq,r4inv,r6inv,reta,lam1r,lam4r,vc2,vc3;
|
|
|
|
r = sqrt(rsq);
|
|
rinvsq = 1.0/rsq;
|
|
r4inv = rinvsq*rinvsq;
|
|
r6inv = rinvsq*r4inv;
|
|
reta = pow(r,-param->eta);
|
|
lam1r = r*param->lam1inv;
|
|
lam4r = r*param->lam4inv;
|
|
vc2 = param->zizj * exp(-lam1r)/r;
|
|
vc3 = param->mbigd * r4inv*exp(-lam4r);
|
|
|
|
fforce = (param->dvrc*r
|
|
- (4.0*vc3 + lam4r*vc3+param->big6w*r6inv
|
|
- param->heta*reta - vc2 - lam1r*vc2)
|
|
) * rinvsq;
|
|
if (eflag) eng = param->bigh*reta
|
|
+ vc2 - vc3 - param->bigw*r6inv
|
|
- r*param->dvrc + param->c0;
|
|
}
|
|
}
|
|
|
|
/* ---------------------------------------------------------------------- */
|
|
|
|
void PairVashishta::threebody(Param *paramij, Param *paramik, Param *paramijk,
|
|
double rsq1, double rsq2,
|
|
double *delr1, double *delr2,
|
|
double *fj, double *fk, int eflag, double &eng)
|
|
{
|
|
double r1,rinvsq1,rainv1,gsrainv1,gsrainvsq1,expgsrainv1;
|
|
double r2,rinvsq2,rainv2,gsrainv2,gsrainvsq2,expgsrainv2;
|
|
double rinv12,cs,delcs,delcssq,facexp,facrad,frad1,frad2,pcsinv,pcsinvsq,pcs;
|
|
double facang,facang12,csfacang,csfac1,csfac2;
|
|
|
|
r1 = sqrt(rsq1);
|
|
rinvsq1 = 1.0/rsq1;
|
|
rainv1 = 1.0/(r1 - paramij->r0);
|
|
gsrainv1 = paramij->gamma * rainv1;
|
|
gsrainvsq1 = gsrainv1*rainv1/r1;
|
|
expgsrainv1 = exp(gsrainv1);
|
|
|
|
r2 = sqrt(rsq2);
|
|
rinvsq2 = 1.0/rsq2;
|
|
rainv2 = 1.0/(r2 - paramik->r0);
|
|
gsrainv2 = paramik->gamma * rainv2;
|
|
gsrainvsq2 = gsrainv2*rainv2/r2;
|
|
expgsrainv2 = exp(gsrainv2);
|
|
|
|
rinv12 = 1.0/(r1*r2);
|
|
cs = (delr1[0]*delr2[0] + delr1[1]*delr2[1] + delr1[2]*delr2[2]) * rinv12;
|
|
delcs = cs - paramijk->costheta;
|
|
delcssq = delcs*delcs;
|
|
pcsinv = paramijk->bigc*delcssq + 1.0;
|
|
pcsinvsq = pcsinv*pcsinv;
|
|
pcs = delcssq/pcsinv;
|
|
|
|
facexp = expgsrainv1*expgsrainv2;
|
|
|
|
facrad = paramijk->bigb * facexp * pcs;
|
|
frad1 = facrad*gsrainvsq1;
|
|
frad2 = facrad*gsrainvsq2;
|
|
facang = paramijk->big2b * facexp * delcs/pcsinvsq;
|
|
facang12 = rinv12*facang;
|
|
csfacang = cs*facang;
|
|
csfac1 = rinvsq1*csfacang;
|
|
|
|
fj[0] = delr1[0]*(frad1+csfac1)-delr2[0]*facang12;
|
|
fj[1] = delr1[1]*(frad1+csfac1)-delr2[1]*facang12;
|
|
fj[2] = delr1[2]*(frad1+csfac1)-delr2[2]*facang12;
|
|
|
|
csfac2 = rinvsq2*csfacang;
|
|
|
|
fk[0] = delr2[0]*(frad2+csfac2)-delr1[0]*facang12;
|
|
fk[1] = delr2[1]*(frad2+csfac2)-delr1[1]*facang12;
|
|
fk[2] = delr2[2]*(frad2+csfac2)-delr1[2]*facang12;
|
|
|
|
if (eflag) eng = facrad;
|
|
}
|