2006-11-11 07:52:37 +08:00
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/* ----------------------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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2007-01-30 08:22:05 +08:00
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http://lammps.sandia.gov, Sandia National Laboratories
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Steve Plimpton, sjplimp@sandia.gov
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2006-11-11 07:52:37 +08:00
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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: Mark Stevens (SNL)
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------------------------------------------------------------------------- */
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#include "math.h"
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#include "stdlib.h"
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#include "string.h"
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#include "fix_wall_lj126.h"
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#include "atom.h"
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#include "domain.h"
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2006-11-11 07:52:37 +08:00
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#include "update.h"
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#include "output.h"
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#include "respa.h"
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#include "error.h"
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2007-01-30 08:22:05 +08:00
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using namespace LAMMPS_NS;
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2006-11-11 07:52:37 +08:00
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/* ---------------------------------------------------------------------- */
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2007-01-30 08:22:05 +08:00
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FixWallLJ126::FixWallLJ126(LAMMPS *lmp, int narg, char **arg) :
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Fix(lmp, narg, arg)
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2006-11-11 07:52:37 +08:00
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{
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if (narg != 8) error->all("Illegal fix wall/lj126 command");
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if (strcmp(arg[3],"xlo") == 0) {
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dim = 0;
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side = -1;
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} else if (strcmp(arg[3],"xhi") == 0) {
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dim = 0;
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side = 1;
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} else if (strcmp(arg[3],"ylo") == 0) {
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dim = 1;
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side = -1;
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} else if (strcmp(arg[3],"yhi") == 0) {
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dim = 1;
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side = 1;
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} else if (strcmp(arg[3],"zlo") == 0) {
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dim = 2;
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side = -1;
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} else if (strcmp(arg[3],"zhi") == 0) {
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dim = 2;
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side = 1;
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} else error->all("Illegal fix wall/lj126 command");
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coord = atof(arg[4]);
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epsilon = atof(arg[5]);
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sigma = atof(arg[6]);
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cutoff = atof(arg[7]);
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coeff1 = 48.0 * epsilon * pow(sigma,12.0);
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coeff2 = 24.0 * epsilon * pow(sigma,6.0);
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coeff3 = 4.0 * epsilon * pow(sigma,12.0);
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coeff4 = 4.0 * epsilon * pow(sigma,6.0);
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double r2inv = 1.0/(cutoff*cutoff);
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double r6inv = r2inv*r2inv*r2inv;
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offset = r6inv*(coeff3*r6inv - coeff4);
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if (dim == 0 && domain->xperiodic)
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error->all("Cannot use wall in periodic dimension");
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if (dim == 1 && domain->yperiodic)
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error->all("Cannot use wall in periodic dimension");
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if (dim == 2 && domain->zperiodic)
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error->all("Cannot use wall in periodic dimension");
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2006-11-11 07:52:37 +08:00
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}
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/* ---------------------------------------------------------------------- */
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int FixWallLJ126::setmask()
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{
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int mask = 0;
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mask |= POST_FORCE;
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2007-01-30 08:22:05 +08:00
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mask |= THERMO_ENERGY;
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2006-11-11 07:52:37 +08:00
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mask |= POST_FORCE_RESPA;
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mask |= MIN_POST_FORCE;
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return mask;
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}
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/* ---------------------------------------------------------------------- */
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void FixWallLJ126::init()
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{
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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 FixWallLJ126::setup()
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{
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eflag_enable = 1;
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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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2007-01-30 08:22:05 +08:00
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eflag_enable = 0;
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2006-11-11 07:52:37 +08:00
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}
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/* ---------------------------------------------------------------------- */
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void FixWallLJ126::min_setup()
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{
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eflag_enable = 1;
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2006-11-11 07:52:37 +08:00
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post_force(1);
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}
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/* ---------------------------------------------------------------------- */
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void FixWallLJ126::post_force(int vflag)
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{
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bool eflag = false;
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2007-01-30 08:22:05 +08:00
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if (eflag_enable) eflag = true;
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else if (output->next_thermo == update->ntimestep) eflag = true;
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2006-11-11 07:52:37 +08:00
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double **x = atom->x;
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double **f = atom->f;
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int *mask = atom->mask;
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int nlocal = atom->nlocal;
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2007-01-30 08:22:05 +08:00
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double delta,rinv,r2inv,r6inv,eng;
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2006-11-11 07:52:37 +08:00
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if (eflag) eng = 0.0;
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for (int i = 0; i < nlocal; i++)
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if (mask[i] & groupbit) {
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if (side == -1) delta = x[i][dim] - coord;
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else delta = coord - x[i][dim];
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if (delta <= 0.0) continue;
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if (delta > cutoff) continue;
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rinv = 1.0/delta;
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r2inv = rinv*rinv;
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r6inv = r2inv*r2inv*r2inv;
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f[i][dim] -= r6inv*(coeff1*r6inv - coeff2) * side;
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if (eflag) eng += r6inv*(coeff3*r6inv - coeff4) - offset;
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}
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if (eflag) MPI_Allreduce(&eng,&etotal,1,MPI_DOUBLE,MPI_SUM,world);
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}
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/* ---------------------------------------------------------------------- */
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void FixWallLJ126::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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/* ---------------------------------------------------------------------- */
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void FixWallLJ126::min_post_force(int vflag)
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{
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post_force(vflag);
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}
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/* ---------------------------------------------------------------------- */
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2007-01-30 08:22:05 +08:00
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double FixWallLJ126::thermo(int n)
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{
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if (n == 0) return etotal;
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else return 0.0;
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2006-11-11 07:52:37 +08:00
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}
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