mirror of https://github.com/lammps/lammps.git
104 lines
2.9 KiB
C++
104 lines
2.9 KiB
C++
/* ----------------------------------------------------------------------
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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: Christina Payne (Vanderbilt U)
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------------------------------------------------------------------------- */
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#include "string.h"
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#include "stdlib.h"
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#include "fix_efield.h"
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#include "atom.h"
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#include "update.h"
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#include "force.h"
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#include "respa.h"
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#include "error.h"
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#include "math.h"
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using namespace LAMMPS_NS;
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/* ---------------------------------------------------------------------- */
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FixEfield::FixEfield(LAMMPS *lmp, int narg, char **arg) :
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Fix(lmp, narg, arg)
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{
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if (narg != 6) error->all("Illegal fix efield command");
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double factor = force->qe2f;
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ex = factor * atof(arg[3]);
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ey = factor * atof(arg[4]);
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ez = factor * atof(arg[5]);
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}
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/* ---------------------------------------------------------------------- */
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int FixEfield::setmask()
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{
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int mask = 0;
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mask |= POST_FORCE;
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mask |= POST_FORCE_RESPA;
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return mask;
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}
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/* ---------------------------------------------------------------------- */
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void FixEfield::init()
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{
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// require an atom style with charge defined
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if (atom->q == NULL)
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error->all("Must use charged atom style with fix efield");
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if (strcmp(update->integrate_style,"respa") == 0)
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nlevels_respa = ((Respa *) update->integrate)->nlevels;
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}
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/* ---------------------------------------------------------------------- */
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void FixEfield::setup()
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{
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if (strcmp(update->integrate_style,"verlet") == 0)
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post_force(1);
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else {
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((Respa *) update->integrate)->copy_flevel_f(nlevels_respa-1);
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post_force_respa(1,nlevels_respa-1,0);
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((Respa *) update->integrate)->copy_f_flevel(nlevels_respa-1);
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}
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}
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/* ----------------------------------------------------------------------
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apply F = qE
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------------------------------------------------------------------------- */
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void FixEfield::post_force(int vflag)
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{
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double **f = atom->f;
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double *q = atom->q;
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int *mask = atom->mask;
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int nlocal = atom->nlocal;
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for (int i = 0; i < nlocal; i++)
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if (mask[i] & groupbit) {
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f[i][0] += q[i]*ex;
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f[i][1] += q[i]*ey;
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f[i][2] += q[i]*ez;
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}
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}
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/* ---------------------------------------------------------------------- */
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void FixEfield::post_force_respa(int vflag, int ilevel, int iloop)
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{
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if (ilevel == nlevels_respa-1) post_force(vflag);
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}
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