89 lines
2.3 KiB
C++
89 lines
2.3 KiB
C++
/* ----------------------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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https://www.lammps.org/, 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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#include "fix_nve_noforce.h"
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#include "atom.h"
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#include "error.h"
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#include "respa.h"
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#include "update.h"
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using namespace LAMMPS_NS;
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using namespace FixConst;
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/* ---------------------------------------------------------------------- */
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FixNVENoforce::FixNVENoforce(LAMMPS *lmp, int narg, char **arg) : Fix(lmp, narg, arg)
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{
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if (narg != 3) utils::missing_cmd_args(FLERR, "fix nve/noforce", error);
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time_integrate = 1;
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}
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/* ---------------------------------------------------------------------- */
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int FixNVENoforce::setmask()
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{
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int mask = 0;
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mask |= INITIAL_INTEGRATE;
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mask |= INITIAL_INTEGRATE_RESPA;
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return mask;
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}
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/* ---------------------------------------------------------------------- */
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void FixNVENoforce::init()
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{
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dtv = update->dt;
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if (utils::strmatch(update->integrate_style, "^respa"))
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step_respa = (dynamic_cast<Respa *>(update->integrate))->step;
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}
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/* ---------------------------------------------------------------------- */
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void FixNVENoforce::initial_integrate(int /*vflag*/)
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{
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double **x = atom->x;
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double **v = atom->v;
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int *mask = atom->mask;
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int nlocal = atom->nlocal;
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if (igroup == atom->firstgroup) nlocal = atom->nfirst;
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for (int i = 0; i < nlocal; i++) {
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if (mask[i] & groupbit) {
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x[i][0] += dtv * v[i][0];
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x[i][1] += dtv * v[i][1];
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x[i][2] += dtv * v[i][2];
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}
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}
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}
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/* ---------------------------------------------------------------------- */
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void FixNVENoforce::initial_integrate_respa(int vflag, int ilevel, int flag)
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{
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if (flag) return; // only used by NPT,NPH
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dtv = step_respa[ilevel];
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if (ilevel == 0) initial_integrate(vflag);
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}
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/* ---------------------------------------------------------------------- */
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void FixNVENoforce::reset_dt()
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{
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dtv = update->dt;
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}
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