Files
lammps/src/fix_wall.cpp

428 lines
13 KiB
C++

/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
https://www.lammps.org/, Sandia National Laboratories
LAMMPS development team: developers@lammps.org
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.
------------------------------------------------------------------------- */
#include "fix_wall.h"
#include "domain.h"
#include "error.h"
#include "input.h"
#include "lattice.h"
#include "modify.h"
#include "respa.h"
#include "update.h"
#include "variable.h"
#include <cstring>
using namespace LAMMPS_NS;
using namespace FixConst;
static const char *wallpos[] = {"xlo", "xhi", "ylo", "yhi", "zlo", "zhi"};
/* ---------------------------------------------------------------------- */
FixWall::FixWall(LAMMPS *lmp, int narg, char **arg) : Fix(lmp, narg, arg), nwall(0)
{
scalar_flag = 1;
vector_flag = 1;
global_freq = 1;
extscalar = 1;
extvector = 1;
energy_global_flag = 1;
virial_global_flag = virial_peratom_flag = 1;
respa_level_support = 1;
ilevel_respa = 0;
// parse args
int scaleflag = 1;
fldflag = 0;
int pbcflag = 0;
for (int i = 0; i < 6; i++) xstr[i] = estr[i] = sstr[i] = lstr[i] = fstr[i] = kstr[i] = nullptr;
int iarg = 3;
if (utils::strmatch(style, "^wall/table")) iarg = 5;
while (iarg < narg) {
int wantargs = 5;
if (utils::strmatch(style, "^wall/lepton")) wantargs = 4;
if (utils::strmatch(style, "^wall/morse")) wantargs = 6;
if ((strcmp(arg[iarg], "xlo") == 0) || (strcmp(arg[iarg], "xhi") == 0) ||
(strcmp(arg[iarg], "ylo") == 0) || (strcmp(arg[iarg], "yhi") == 0) ||
(strcmp(arg[iarg], "zlo") == 0) || (strcmp(arg[iarg], "zhi") == 0)) {
if (iarg + wantargs > narg) error->all(FLERR, "Missing argument for fix {} command", style);
int newwall;
if (strcmp(arg[iarg], "xlo") == 0) {
newwall = XLO;
} else if (strcmp(arg[iarg], "xhi") == 0) {
newwall = XHI;
} else if (strcmp(arg[iarg], "ylo") == 0) {
newwall = YLO;
} else if (strcmp(arg[iarg], "yhi") == 0) {
newwall = YHI;
} else if (strcmp(arg[iarg], "zlo") == 0) {
newwall = ZLO;
} else if (strcmp(arg[iarg], "zhi") == 0) {
newwall = ZHI;
}
for (int m = 0; (m < nwall) && (m < 6); m++) {
if (newwall == wallwhich[m])
error->all(FLERR, "{} wall defined twice in fix {} command", wallpos[newwall], style);
}
wallwhich[nwall] = newwall;
if (strcmp(arg[iarg + 1], "EDGE") == 0) {
xstyle[nwall] = EDGE;
int dim = wallwhich[nwall] / 2;
int side = wallwhich[nwall] % 2;
if (side == 0) {
coord0[nwall] = domain->boxlo[dim];
} else {
coord0[nwall] = domain->boxhi[dim];
}
} else if (utils::strmatch(arg[iarg + 1], "^v_")) {
xstyle[nwall] = VARIABLE;
xstr[nwall] = utils::strdup(arg[iarg + 1] + 2);
} else {
xstyle[nwall] = CONSTANT;
coord0[nwall] = utils::numeric(FLERR, arg[iarg + 1], false, lmp);
}
if (utils::strmatch(style, "^wall/lepton")) {
estyle[nwall] = sstyle[nwall] = CONSTANT;
lstr[nwall] = utils::strdup(arg[iarg + 2]);
cutoff[nwall] = utils::numeric(FLERR, arg[iarg + 3], false, lmp);
} else if (utils::strmatch(style, "^wall/table")) {
estyle[nwall] = sstyle[nwall] = CONSTANT;
fstr[nwall] = utils::strdup(arg[iarg + 2]);
kstr[nwall] = utils::strdup(arg[iarg + 3]);
cutoff[nwall] = utils::numeric(FLERR, arg[iarg + 4], false, lmp);
} else {
if (iarg + 5 > narg) error->all(FLERR, "Missing argument for fix {} command", style);
if (utils::strmatch(arg[iarg + 2], "^v_")) {
estr[nwall] = utils::strdup(arg[iarg + 2] + 2);
estyle[nwall] = VARIABLE;
} else {
epsilon[nwall] = utils::numeric(FLERR, arg[iarg + 2], false, lmp);
estyle[nwall] = CONSTANT;
}
if (utils::strmatch(style, "^wall/morse")) {
if (utils::strmatch(arg[iarg + 3], "^v_")) {
astr[nwall] = utils::strdup(arg[iarg + 3] + 2);
astyle[nwall] = VARIABLE;
} else {
alpha[nwall] = utils::numeric(FLERR, arg[iarg + 3], false, lmp);
astyle[nwall] = CONSTANT;
}
// adjust so we can share the regular code path
++iarg;
--wantargs;
}
if (utils::strmatch(arg[iarg + 3], "^v_")) {
sstr[nwall] = utils::strdup(arg[iarg + 3] + 2);
sstyle[nwall] = VARIABLE;
} else {
sigma[nwall] = utils::numeric(FLERR, arg[iarg + 3], false, lmp);
sstyle[nwall] = CONSTANT;
}
cutoff[nwall] = utils::numeric(FLERR, arg[iarg + 4], false, lmp);
}
nwall++;
iarg += wantargs;
} else if (strcmp(arg[iarg], "units") == 0) {
if (iarg + 2 > narg) error->all(FLERR, "Illegal fix {} command", style);
if (strcmp(arg[iarg + 1], "box") == 0)
scaleflag = 0;
else if (strcmp(arg[iarg + 1], "lattice") == 0)
scaleflag = 1;
else
error->all(FLERR, "Illegal fix {} command", style);
iarg += 2;
} else if (strcmp(arg[iarg], "fld") == 0) {
if (iarg + 2 > narg) error->all(FLERR, "Illegal fix {} command", style);
fldflag = utils::logical(FLERR, arg[iarg + 1], false, lmp);
iarg += 2;
} else if (strcmp(arg[iarg], "pbc") == 0) {
if (iarg + 2 > narg) error->all(FLERR, "Illegal fix {} command", style);
pbcflag = utils::logical(FLERR, arg[iarg + 1], false, lmp);
iarg += 2;
} else
error->all(FLERR, "Illegal fix {} command", style);
}
size_vector = nwall;
// error checks
if (nwall == 0) error->all(FLERR, "Illegal fix {} command: no walls defined", style);
for (int m = 0; m < nwall; m++) {
if (cutoff[m] <= 0.0)
error->all(FLERR, "Fix {} cutoff <= 0.0 for {} wall", style, wallpos[wallwhich[m]]);
}
for (int m = 0; m < nwall; m++)
if ((wallwhich[m] == ZLO || wallwhich[m] == ZHI) && domain->dimension == 2)
error->all(FLERR, "Cannot use fix {} zlo/zhi for a 2d simulation", style);
if (!pbcflag) {
for (int m = 0; m < nwall; m++) {
if ((wallwhich[m] == XLO || wallwhich[m] == XHI) && domain->xperiodic)
error->all(FLERR, "Cannot use {} wall in periodic x dimension", wallpos[wallwhich[m]]);
if ((wallwhich[m] == YLO || wallwhich[m] == YHI) && domain->yperiodic)
error->all(FLERR, "Cannot use {} wall in periodic y dimension", wallpos[wallwhich[m]]);
if ((wallwhich[m] == ZLO || wallwhich[m] == ZHI) && domain->zperiodic)
error->all(FLERR, "Cannot use {} wall in periodic z dimension", wallpos[wallwhich[m]]);
}
}
// scale factors for wall position for CONSTANT and VARIABLE walls
int flag = 0;
for (int m = 0; m < nwall; m++)
if (xstyle[m] != EDGE) flag = 1;
if (flag) {
if (scaleflag) {
xscale = domain->lattice->xlattice;
yscale = domain->lattice->ylattice;
zscale = domain->lattice->zlattice;
} else
xscale = yscale = zscale = 1.0;
for (int m = 0; m < nwall; m++) {
if (xstyle[m] != CONSTANT) continue;
if (wallwhich[m] < YLO)
coord0[m] *= xscale;
else if (wallwhich[m] < ZLO)
coord0[m] *= yscale;
else
coord0[m] *= zscale;
}
}
// set xflag if any wall positions are variable
// set varflag if any wall positions or parameters are variable
// set wstyle to VARIABLE if either epsilon or sigma is a variable
varflag = xflag = 0;
for (int m = 0; m < nwall; m++) {
if (xstyle[m] == VARIABLE) xflag = 1;
if (xflag || estyle[m] == VARIABLE || sstyle[m] == VARIABLE) varflag = 1;
if (estyle[m] == VARIABLE || sstyle[m] == VARIABLE)
wstyle[m] = VARIABLE;
else
wstyle[m] = CONSTANT;
}
eflag = 0;
for (int m = 0; m <= nwall; m++) ewall[m] = 0.0;
}
/* ---------------------------------------------------------------------- */
FixWall::~FixWall()
{
if (copymode) return;
for (int m = 0; m < nwall; m++) {
delete[] xstr[m];
delete[] estr[m];
delete[] sstr[m];
delete[] lstr[m];
delete[] fstr[m];
delete[] kstr[m];
}
}
/* ---------------------------------------------------------------------- */
int FixWall::setmask()
{
int mask = 0;
// FLD implicit needs to invoke wall forces before pair style
if (fldflag)
mask |= PRE_FORCE;
else
mask |= POST_FORCE;
mask |= POST_FORCE_RESPA;
mask |= MIN_POST_FORCE;
return mask;
}
/* ---------------------------------------------------------------------- */
void FixWall::init()
{
for (int m = 0; m < nwall; m++) {
if (xstyle[m] == VARIABLE) {
xindex[m] = input->variable->find(xstr[m]);
if (xindex[m] < 0) error->all(FLERR, "Variable name for fix wall does not exist");
if (!input->variable->equalstyle(xindex[m]))
error->all(FLERR, "Variable for fix wall is invalid style");
}
if (estyle[m] == VARIABLE) {
eindex[m] = input->variable->find(estr[m]);
if (eindex[m] < 0) error->all(FLERR, "Variable name for fix wall does not exist");
if (!input->variable->equalstyle(eindex[m]))
error->all(FLERR, "Variable for fix wall is invalid style");
}
if (sstyle[m] == VARIABLE) {
sindex[m] = input->variable->find(sstr[m]);
if (sindex[m] < 0) error->all(FLERR, "Variable name for fix wall does not exist");
if (!input->variable->equalstyle(sindex[m]))
error->all(FLERR, "Variable for fix wall is invalid style");
}
}
// setup coefficients
for (int m = 0; m < nwall; m++) precompute(m);
if (utils::strmatch(update->integrate_style, "^respa")) {
ilevel_respa = (dynamic_cast<Respa *>(update->integrate))->nlevels - 1;
if (respa_level >= 0) ilevel_respa = MIN(respa_level, ilevel_respa);
}
}
/* ---------------------------------------------------------------------- */
void FixWall::setup(int vflag)
{
if (utils::strmatch(update->integrate_style, "^verlet")) {
if (!fldflag) post_force(vflag);
} else {
(dynamic_cast<Respa *>(update->integrate))->copy_flevel_f(ilevel_respa);
post_force_respa(vflag, ilevel_respa, 0);
(dynamic_cast<Respa *>(update->integrate))->copy_f_flevel(ilevel_respa);
}
}
/* ---------------------------------------------------------------------- */
void FixWall::min_setup(int vflag)
{
post_force(vflag);
}
/* ----------------------------------------------------------------------
only called if fldflag set, in place of post_force
------------------------------------------------------------------------- */
void FixWall::pre_force(int vflag)
{
post_force(vflag);
}
/* ---------------------------------------------------------------------- */
void FixWall::post_force(int vflag)
{
// virial setup
v_init(vflag);
// energy intialize.
// eflag is used to track whether wall energies have been communicated.
eflag = 0;
for (int m = 0; m <= nwall; m++) ewall[m] = 0.0;
// coord = current position of wall
// evaluate variables if necessary, wrap with clear/add
// for epsilon/sigma variables need to re-invoke precompute()
if (varflag) modify->clearstep_compute();
double coord;
for (int m = 0; m < nwall; m++) {
if (xstyle[m] == VARIABLE) {
coord = input->variable->compute_equal(xindex[m]);
if (wallwhich[m] < YLO)
coord *= xscale;
else if (wallwhich[m] < ZLO)
coord *= yscale;
else
coord *= zscale;
} else
coord = coord0[m];
if (wstyle[m] == VARIABLE) {
if (estyle[m] == VARIABLE) {
epsilon[m] = input->variable->compute_equal(eindex[m]);
if (epsilon[m] < 0.0) error->all(FLERR, "Variable evaluation in fix wall gave bad value");
}
if (sstyle[m] == VARIABLE) {
sigma[m] = input->variable->compute_equal(sindex[m]);
if (sigma[m] < 0.0) error->all(FLERR, "Variable evaluation in fix wall gave bad value");
}
precompute(m);
}
wall_particle(m, wallwhich[m], coord);
}
if (varflag) modify->addstep_compute(update->ntimestep + 1);
}
/* ---------------------------------------------------------------------- */
void FixWall::post_force_respa(int vflag, int ilevel, int /*iloop*/)
{
if (ilevel == ilevel_respa) post_force(vflag);
}
/* ---------------------------------------------------------------------- */
void FixWall::min_post_force(int vflag)
{
post_force(vflag);
}
/* ----------------------------------------------------------------------
energy of wall interaction
------------------------------------------------------------------------- */
double FixWall::compute_scalar()
{
// only sum across procs one time
if (eflag == 0) {
MPI_Allreduce(ewall, ewall_all, nwall + 1, MPI_DOUBLE, MPI_SUM, world);
eflag = 1;
}
return ewall_all[0];
}
/* ----------------------------------------------------------------------
components of force on wall
------------------------------------------------------------------------- */
double FixWall::compute_vector(int n)
{
// only sum across procs one time
if (eflag == 0) {
MPI_Allreduce(ewall, ewall_all, nwall + 1, MPI_DOUBLE, MPI_SUM, world);
eflag = 1;
}
return ewall_all[n + 1];
}