Page MenuHomec4science
Files F90688975

fix_wall_lj126.cpp
No OneTemporary
Actions

File Metadata

Created
Sun, Nov 3, 21:47

fix_wall_lj126.cpp
View Options

/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
www.cs.sandia.gov/~sjplimp/lammps.html
Steve Plimpton, sjplimp@sandia.gov, Sandia National Laboratories
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: Mark Stevens (SNL)
------------------------------------------------------------------------- */
#include "math.h"
#include "stdlib.h"
#include "string.h"
#include "fix_wall_lj126.h"
#include "atom.h"
#include "update.h"
#include "output.h"
#include "respa.h"
#include "error.h"
/* ---------------------------------------------------------------------- */
FixWallLJ126::FixWallLJ126(int narg, char **arg) : Fix(narg, arg)
{
if (narg != 8) error->all("Illegal fix wall/lj126 command");
if (strcmp(arg[3],"xlo") == 0) {
dim = 0;
side = -1;
} else if (strcmp(arg[3],"xhi") == 0) {
dim = 0;
side = 1;
} else if (strcmp(arg[3],"ylo") == 0) {
dim = 1;
side = -1;
} else if (strcmp(arg[3],"yhi") == 0) {
dim = 1;
side = 1;
} else if (strcmp(arg[3],"zlo") == 0) {
dim = 2;
side = -1;
} else if (strcmp(arg[3],"zhi") == 0) {
dim = 2;
side = 1;
} else error->all("Illegal fix wall/lj126 command");
coord = atof(arg[4]);
epsilon = atof(arg[5]);
sigma = atof(arg[6]);
cutoff = atof(arg[7]);
coeff1 = 48.0 * epsilon * pow(sigma,12.0);
coeff2 = 24.0 * epsilon * pow(sigma,6.0);
coeff3 = 4.0 * epsilon * pow(sigma,12.0);
coeff4 = 4.0 * epsilon * pow(sigma,6.0);
double r2inv = 1.0/(cutoff*cutoff);
double r6inv = r2inv*r2inv*r2inv;
offset = r6inv*(coeff3*r6inv - coeff4);
}
/* ---------------------------------------------------------------------- */
int FixWallLJ126::setmask()
{
int mask = 0;
mask |= POST_FORCE;
mask |= THERMO;
mask |= POST_FORCE_RESPA;
mask |= MIN_POST_FORCE;
return mask;
}
/* ---------------------------------------------------------------------- */
void FixWallLJ126::init()
{
if (strcmp(update->integrate_style,"respa") == 0)
nlevels_respa = ((Respa *) update->integrate)->nlevels;
if (thermo_print || thermo_energy) thermo_flag = 1;
else thermo_flag = 0;
}
/* ---------------------------------------------------------------------- */
void FixWallLJ126::setup()
{
eflag_on = 1;
if (strcmp(update->integrate_style,"verlet") == 0)
post_force(1);
else {
((Respa *) update->integrate)->copy_flevel_f(nlevels_respa-1);
post_force_respa(1,nlevels_respa-1,0);
((Respa *) update->integrate)->copy_f_flevel(nlevels_respa-1);
}
eflag_on = 0;
}
/* ---------------------------------------------------------------------- */
void FixWallLJ126::min_setup()
{
eflag_on = 1;
post_force(1);
}
/* ---------------------------------------------------------------------- */
void FixWallLJ126::post_force(int vflag)
{
bool eflag = false;
if (thermo_flag) {
if (eflag_on) eflag = true;
else if (output->next_thermo == update->ntimestep) eflag = true;
}
double **x = atom->x;
double **f = atom->f;
int *mask = atom->mask;
int nlocal = atom->nlocal;
double delta,rinv,r2inv,r6inv;
if (eflag) eng = 0.0;
for (int i = 0; i < nlocal; i++)
if (mask[i] & groupbit) {
if (side == -1) delta = x[i][dim] - coord;
else delta = coord - x[i][dim];
if (delta <= 0.0) continue;
if (delta > cutoff) continue;
rinv = 1.0/delta;
r2inv = rinv*rinv;
r6inv = r2inv*r2inv*r2inv;
f[i][dim] -= r6inv*(coeff1*r6inv - coeff2) * side;
if (eflag) eng += r6inv*(coeff3*r6inv - coeff4) - offset;
}
if (eflag) MPI_Allreduce(&eng,&etotal,1,MPI_DOUBLE,MPI_SUM,world);
}
/* ---------------------------------------------------------------------- */
void FixWallLJ126::post_force_respa(int vflag, int ilevel, int iloop)
{
if (ilevel == nlevels_respa-1) post_force(vflag);
}
/* ---------------------------------------------------------------------- */
void FixWallLJ126::min_post_force(int vflag)
{
post_force(vflag);
}
/* ---------------------------------------------------------------------- */
int FixWallLJ126::thermo_fields(int n, int *flags, char **keywords)
{
if (n == 0) return 1;
flags[0] = 3;
strcpy(keywords[0],"Wall");
return 1;
}
/* ---------------------------------------------------------------------- */
int FixWallLJ126::thermo_compute(double *values)
{
values[0] = etotal;
return 1;
}

Event Timeline

c4science · Help