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fix_deform.cpp
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Wed, Oct 16, 14:37

fix_deform.cpp
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/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
http://lammps.sandia.gov, Sandia National Laboratories
Steve Plimpton, sjplimp@sandia.gov
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: Pieter in 't Veld (SNL)
------------------------------------------------------------------------- */
#include "string.h"
#include "stdlib.h"
#include "math.h"
#include "fix_deform.h"
#include "atom.h"
#include "update.h"
#include "comm.h"
#include "domain.h"
#include "lattice.h"
#include "force.h"
#include "modify.h"
#include "kspace.h"
#include "error.h"
using namespace LAMMPS_NS;
enum{NONE,FINAL,DELTA,SCALE,VEL,ERATE,TRATE,VOLUME,WIGGLE};
enum{ONE_FROM_ONE,ONE_FROM_TWO,TWO_FROM_ONE};
// same as domain.cpp, fix_nvt_sllod.cpp, compute_temp_deform.cpp
enum{NO_REMAP,X_REMAP,V_REMAP};
/* ---------------------------------------------------------------------- */
FixDeform::FixDeform(LAMMPS *lmp, int narg, char **arg) : Fix(lmp, narg, arg)
{
if (narg < 4) error->all("Illegal fix deform command");
box_change = 1;
no_change_box = 1;
nevery = atoi(arg[3]);
if (nevery <= 0) error->all("Illegal fix deform command");
// set defaults
set = new Set[6];
set[0].style = set[1].style = set[2].style =
set[3].style = set[4].style = set[5].style = NONE;
// parse arguments
triclinic = domain->triclinic;
int index;
int iarg = 4;
while (iarg < narg) {
if (strcmp(arg[iarg],"x") == 0 ||
strcmp(arg[iarg],"y") == 0 ||
strcmp(arg[iarg],"z") == 0) {
if (strcmp(arg[iarg],"x") == 0) index = 0;
else if (strcmp(arg[iarg],"y") == 0) index = 1;
else if (strcmp(arg[iarg],"z") == 0) index = 2;
if (iarg+2 > narg) error->all("Illegal fix deform command");
if (strcmp(arg[iarg+1],"final") == 0) {
if (iarg+4 > narg) error->all("Illegal fix deform command");
set[index].style = FINAL;
set[index].flo = atof(arg[iarg+2]);
set[index].fhi = atof(arg[iarg+3]);
iarg += 4;
} else if (strcmp(arg[iarg+1],"delta") == 0) {
if (iarg+4 > narg) error->all("Illegal fix deform command");
set[index].style = DELTA;
set[index].dlo = atof(arg[iarg+2]);
set[index].dhi = atof(arg[iarg+3]);
iarg += 4;
} else if (strcmp(arg[iarg+1],"scale") == 0) {
if (iarg+3 > narg) error->all("Illegal fix deform command");
set[index].style = SCALE;
set[index].scale = atof(arg[iarg+2]);
iarg += 3;
} else if (strcmp(arg[iarg+1],"vel") == 0) {
if (iarg+3 > narg) error->all("Illegal fix deform command");
set[index].style = VEL;
set[index].vel = atof(arg[iarg+2]);
iarg += 3;
} else if (strcmp(arg[iarg+1],"erate") == 0) {
if (iarg+3 > narg) error->all("Illegal fix deform command");
set[index].style = ERATE;
set[index].rate = atof(arg[iarg+2]);
iarg += 3;
} else if (strcmp(arg[iarg+1],"trate") == 0) {
if (iarg+3 > narg) error->all("Illegal fix deform command");
set[index].style = TRATE;
set[index].rate = atof(arg[iarg+2]);
iarg += 3;
} else if (strcmp(arg[iarg+1],"volume") == 0) {
set[index].style = VOLUME;
iarg += 2;
} else if (strcmp(arg[iarg+1],"wiggle") == 0) {
if (iarg+4 > narg) error->all("Illegal fix deform command");
set[index].style = WIGGLE;
set[index].amplitude = atof(arg[iarg+2]);
set[index].tperiod = atof(arg[iarg+3]);
if (set[index].tperiod <= 0.0)
error->all("Illegal fix deform command");
iarg += 4;
} else error->all("Illegal fix deform command");
} else if (strcmp(arg[iarg],"xy") == 0 ||
strcmp(arg[iarg],"xz") == 0 ||
strcmp(arg[iarg],"yz") == 0) {
if (triclinic == 0)
error->all("Fix deform tilt factors require triclinic box");
if (strcmp(arg[iarg],"xy") == 0) index = 5;
else if (strcmp(arg[iarg],"xz") == 0) index = 4;
else if (strcmp(arg[iarg],"yz") == 0) index = 3;
if (iarg+2 > narg) error->all("Illegal fix deform command");
if (strcmp(arg[iarg+1],"final") == 0) {
if (iarg+3 > narg) error->all("Illegal fix deform command");
set[index].style = FINAL;
set[index].ftilt = atof(arg[iarg+2]);
iarg += 3;
} else if (strcmp(arg[iarg+1],"delta") == 0) {
if (iarg+3 > narg) error->all("Illegal fix deform command");
set[index].style = DELTA;
set[index].dtilt = atof(arg[iarg+2]);
iarg += 3;
} else if (strcmp(arg[iarg+1],"vel") == 0) {
if (iarg+3 > narg) error->all("Illegal fix deform command");
set[index].style = VEL;
set[index].vel = atof(arg[iarg+2]);
iarg += 3;
} else if (strcmp(arg[iarg+1],"erate") == 0) {
if (iarg+3 > narg) error->all("Illegal fix deform command");
set[index].style = ERATE;
set[index].rate = atof(arg[iarg+2]);
iarg += 3;
} else if (strcmp(arg[iarg+1],"trate") == 0) {
if (iarg+3 > narg) error->all("Illegal fix deform command");
set[index].style = TRATE;
set[index].rate = atof(arg[iarg+2]);
iarg += 3;
} else if (strcmp(arg[iarg+1],"wiggle") == 0) {
if (iarg+4 > narg) error->all("Illegal fix deform command");
set[index].style = WIGGLE;
set[index].amplitude = atof(arg[iarg+2]);
set[index].tperiod = atof(arg[iarg+3]);
if (set[index].tperiod <= 0.0)
error->all("Illegal fix deform command");
iarg += 4;
} else error->all("Illegal fix deform command");
} else break;
}
// read options from end of input line
options(narg-iarg,&arg[iarg]);
// setup dimflags used by other classes to check for volume-change conflicts
for (int i = 0; i < 6; i++)
if (set[i].style == NONE) dimflag[i] = 0;
else dimflag[i] = 1;
// check periodicity
if ((set[0].style && domain->xperiodic == 0) ||
(set[1].style && domain->yperiodic == 0) ||
(set[2].style && domain->zperiodic == 0))
error->all("Cannot fix deform on a non-periodic boundary");
if (set[3].style && (domain->yperiodic == 0 || domain->zperiodic == 0))
error->all("Cannot fix deform on a non-periodic boundary");
if (set[4].style && (domain->xperiodic == 0 || domain->zperiodic == 0))
error->all("Cannot fix deform on a non-periodic boundary");
if (set[5].style && (domain->xperiodic == 0 || domain->yperiodic == 0))
error->all("Cannot fix deform on a non-periodic boundary");
// apply scaling to FINAL,DELTA,VEL,WIGGLE since they have distance/vel units
int flag = 0;
for (int i = 0; i < 6; i++)
if (set[i].style == FINAL || set[i].style == DELTA ||
set[i].style == VEL || set[i].style == WIGGLE) flag = 1;
if (flag && scaleflag && domain->lattice == NULL)
error->all("Use of fix deform with undefined lattice");
double xscale,yscale,zscale;
if (flag && scaleflag) {
xscale = domain->lattice->xlattice;
yscale = domain->lattice->ylattice;
zscale = domain->lattice->zlattice;
}
else xscale = yscale = zscale = 1.0;
// for 3,4,5: scaling is in 1st dimension, e.g. x for xz
double map[6];
map[0] = xscale; map[1] = yscale; map[2] = zscale;
map[3] = yscale; map[4] = xscale; map[5] = xscale;
for (int i = 0; i < 3; i++) {
if (set[i].style == FINAL) {
set[i].flo *= map[i];
set[i].fhi *= map[i];
} else if (set[i].style == DELTA) {
set[i].dlo *= map[i];
set[i].dhi *= map[i];
} else if (set[i].style == VEL) {
set[i].vel *= map[i];
} else if (set[i].style == WIGGLE) {
set[i].amplitude *= map[i];
}
}
for (int i = 3; i < 6; i++) {
if (set[i].style == FINAL) set[i].ftilt *= map[i];
else if (set[i].style == DELTA) set[i].dtilt *= map[i];
else if (set[i].style == VEL) set[i].vel *= map[i];
else if (set[i].style == WIGGLE) set[i].amplitude *= map[i];
}
// for VOLUME, setup links to other dims
// fixed, dynamic1, dynamic2
for (int i = 0; i < 3; i++) {
if (set[i].style != VOLUME) continue;
int other1 = (i+1) % 3;
int other2 = (i+2) % 3;
if (set[other1].style == NONE) {
if (set[other2].style == NONE || set[other2].style == VOLUME)
error->all("Fix deform volume setting is invalid");
set[i].substyle = ONE_FROM_ONE;
set[i].fixed = other1;
set[i].dynamic1 = other2;
} else if (set[other2].style == NONE) {
if (set[other1].style == NONE || set[other1].style == VOLUME)
error->all("Fix deform volume setting is invalid");
set[i].substyle = ONE_FROM_ONE;
set[i].fixed = other2;
set[i].dynamic1 = other1;
} else if (set[other1].style == VOLUME) {
if (set[other2].style == NONE || set[other2].style == VOLUME)
error->all("Fix deform volume setting is invalid");
set[i].substyle = TWO_FROM_ONE;
set[i].fixed = other1;
set[i].dynamic1 = other2;
} else if (set[other2].style == VOLUME) {
if (set[other1].style == NONE || set[other1].style == VOLUME)
error->all("Fix deform volume setting is invalid");
set[i].substyle = TWO_FROM_ONE;
set[i].fixed = other2;
set[i].dynamic1 = other1;
} else {
set[i].substyle = ONE_FROM_TWO;
set[i].dynamic1 = other1;
set[i].dynamic2 = other2;
}
}
// set initial values at time fix deform is issued
for (int i = 0; i < 3; i++) {
set[i].lo_initial = domain->boxlo[i];
set[i].hi_initial = domain->boxhi[i];
set[i].vol_initial = domain->xprd * domain->yprd * domain->zprd;
}
for (int i = 3; i < 6; i++) {
if (i == 5) set[i].tilt_initial = domain->xy;
else if (i == 4) set[i].tilt_initial = domain->xz;
else if (i == 3) set[i].tilt_initial = domain->yz;
}
// reneighboring only forced if flips will occur due to shape changes
if (set[3].style || set[4].style || set[5].style) force_reneighbor = 1;
next_reneighbor = -1;
nrigid = 0;
rfix = NULL;
flip = 0;
TWOPI = 8.0*atan(1.0);
}
/* ---------------------------------------------------------------------- */
FixDeform::~FixDeform()
{
delete [] set;
delete [] rfix;
// reset domain's h_rate = 0.0, since this fix may have made it non-zero
double *h_rate = domain->h_rate;
double *h_ratelo = domain->h_ratelo;
h_rate[0] = h_rate[1] = h_rate[2] =
h_rate[3] = h_rate[4] = h_rate[5] = 0.0;
h_ratelo[0] = h_ratelo[1] = h_ratelo[2] = 0.0;
}
/* ---------------------------------------------------------------------- */
int FixDeform::setmask()
{
int mask = 0;
mask |= PRE_EXCHANGE;
mask |= END_OF_STEP;
return mask;
}
/* ---------------------------------------------------------------------- */
void FixDeform::init()
{
// error if more than one fix deform
// domain, fix nvt/sllod, compute temp/deform only work on single h_rate
int count = 0;
for (int i = 0; i < modify->nfix; i++)
if (strcmp(modify->fix[i]->style,"deform") == 0) count++;
if (count > 1) error->all("More than one fix deform");
// Kspace setting
if (force->kspace) kspace_flag = 1;
else kspace_flag = 0;
// elapsed time for entire simulation, including multiple runs if defined
double delt = (update->endstep - update->beginstep) * update->dt;
// set start/stop values for box size and shape
// if single run, start is current values
// if multiple runs enabled via run start/stop settings,
// start is value when fix deform was issued
// if NONE, no need to set
for (int i = 0; i < 3; i++) {
if (update->firststep == update->beginstep) {
set[i].lo_start = domain->boxlo[i];
set[i].hi_start = domain->boxhi[i];
set[i].vol_start = domain->xprd * domain->yprd * domain->zprd;
} else {
set[i].lo_start = set[i].lo_initial;
set[i].hi_start = set[i].hi_initial;
set[i].vol_start = set[i].vol_initial;
}
if (set[i].style == FINAL) {
set[i].lo_stop = set[i].flo;
set[i].hi_stop = set[i].fhi;
} else if (set[i].style == DELTA) {
set[i].lo_stop = set[i].lo_start + set[i].dlo;
set[i].hi_stop = set[i].hi_start + set[i].dhi;
} else if (set[i].style == SCALE) {
set[i].lo_stop = 0.5*(set[i].lo_start+set[i].hi_start) -
0.5*set[i].scale*(set[i].hi_start-set[i].lo_start);
set[i].hi_stop = 0.5*(set[i].lo_start+set[i].hi_start) +
0.5*set[i].scale*(set[i].hi_start-set[i].lo_start);
} else if (set[i].style == VEL) {
set[i].lo_stop = set[i].lo_start - 0.5*delt*set[i].vel;
set[i].hi_stop = set[i].hi_start + 0.5*delt*set[i].vel;
} else if (set[i].style == ERATE) {
set[i].lo_stop = set[i].lo_start -
0.5*delt*set[i].rate * (set[i].hi_start-set[i].lo_start);
set[i].hi_stop = set[i].hi_start +
0.5*delt*set[i].rate * (set[i].hi_start-set[i].lo_start);
if (set[i].hi_stop <= set[i].lo_stop)
error->all("Final box dimension due to fix deform is < 0.0");
} else if (set[i].style == TRATE) {
set[i].lo_stop = 0.5*(set[i].lo_start+set[i].hi_start) -
0.5*((set[i].hi_start-set[i].lo_start) * exp(set[i].rate*delt));
set[i].hi_stop = 0.5*(set[i].lo_start+set[i].hi_start) +
0.5*((set[i].hi_start-set[i].lo_start) * exp(set[i].rate*delt));
} else if (set[i].style == WIGGLE) {
set[i].lo_stop = set[i].lo_start -
0.5*set[i].amplitude * sin(TWOPI*delt/set[i].tperiod);
set[i].hi_stop = set[i].hi_start +
0.5*set[i].amplitude * sin(TWOPI*delt/set[i].tperiod);
}
}
for (int i = 3; i < 6; i++) {
if (update->firststep == update->beginstep) {
if (i == 5) set[i].tilt_start = domain->xy;
else if (i == 4) set[i].tilt_start = domain->xz;
else if (i == 3) set[i].tilt_start = domain->yz;
} else set[i].tilt_start = set[i].tilt_initial;
if (set[i].style == FINAL) {
set[i].tilt_stop = set[i].ftilt;
} else if (set[i].style == DELTA) {
set[i].tilt_stop = set[i].tilt_start + set[i].dtilt;
} else if (set[i].style == VEL) {
set[i].tilt_stop = set[i].tilt_start + delt*set[i].vel;
} else if (set[i].style == ERATE) {
if (i == 3) set[i].tilt_stop = set[i].tilt_start +
delt*set[i].rate * (set[2].hi_start-set[2].lo_start);
if (i == 4) set[i].tilt_stop = set[i].tilt_start +
delt*set[i].rate * (set[2].hi_start-set[2].lo_start);
if (i == 5) set[i].tilt_stop = set[i].tilt_start +
delt*set[i].rate * (set[1].hi_start-set[1].lo_start);
} else if (set[i].style == TRATE) {
set[i].tilt_stop = set[i].tilt_start * exp(set[i].rate*delt);
} else if (set[i].style == WIGGLE) {
set[i].tilt_stop = set[i].tilt_start +
set[i].amplitude * sin(TWOPI*delt/set[i].tperiod);
// compute min/max for WIGGLE = extrema tilt factor will ever reach
if (set[i].amplitude >= 0.0) {
if (delt < 0.25*set[i].tperiod) {
set[i].tilt_min = set[i].tilt_start;
set[i].tilt_max = set[i].tilt_start +
set[i].amplitude*sin(TWOPI*delt/set[i].tperiod);
} else if (delt < 0.5*set[i].tperiod) {
set[i].tilt_min = set[i].tilt_start;
set[i].tilt_max = set[i].tilt_start + set[i].amplitude;
} else if (delt < 0.75*set[i].tperiod) {
set[i].tilt_min = set[i].tilt_start -
set[i].amplitude*sin(TWOPI*delt/set[i].tperiod);
set[i].tilt_max = set[i].tilt_start + set[i].amplitude;
} else {
set[i].tilt_min = set[i].tilt_start - set[i].amplitude;
set[i].tilt_max = set[i].tilt_start + set[i].amplitude;
}
} else {
if (delt < 0.25*set[i].tperiod) {
set[i].tilt_min = set[i].tilt_start -
set[i].amplitude*sin(TWOPI*delt/set[i].tperiod);
set[i].tilt_max = set[i].tilt_start;
} else if (delt < 0.5*set[i].tperiod) {
set[i].tilt_min = set[i].tilt_start - set[i].amplitude;
set[i].tilt_max = set[i].tilt_start;
} else if (delt < 0.75*set[i].tperiod) {
set[i].tilt_min = set[i].tilt_start - set[i].amplitude;
set[i].tilt_max = set[i].tilt_start +
set[i].amplitude*sin(TWOPI*delt/set[i].tperiod);
} else {
set[i].tilt_min = set[i].tilt_start - set[i].amplitude;
set[i].tilt_max = set[i].tilt_start + set[i].amplitude;
}
}
}
}
// if using tilt TRATE, then initial tilt must be non-zero
for (int i = 3; i < 6; i++)
if (set[i].style == TRATE && set[i].tilt_start == 0.0)
error->all("Cannot use fix deform trate on a box with zero tilt");
// if yz changes and will cause box flip, then xy cannot be changing
// test for WIGGLE is on min/max oscillation limit, not tilt_stop
// this is b/c the flips would induce continuous changes in xz
// in order to keep the edge vectors of the flipped shape matrix
// a linear combination of the edge vectors of the unflipped shape matrix
if (set[3].style && set[5].style) {
int flag = 0;
double lo,hi;
if (set[3].style == WIGGLE) {
lo = set[3].tilt_min;
hi = set[3].tilt_max;
} else lo = hi = set[3].tilt_stop;
if (lo < -0.5*(set[1].hi_start-set[1].lo_start) ||
hi > 0.5*(set[1].hi_start-set[1].lo_start)) flag = 1;
if (set[1].style) {
if (lo < -0.5*(set[1].hi_stop-set[1].lo_stop) ||
hi > 0.5*(set[1].hi_stop-set[1].lo_stop)) flag = 1;
}
if (flag)
error->all("Fix deform is changing yz by too much with changing xy");
}
// set domain->h_rate values for use by domain and other fixes/computes
// initialize all rates to 0.0
// cannot set here for TRATE,VOLUME,WIGGLE styles since not constant
h_rate = domain->h_rate;
h_ratelo = domain->h_ratelo;
for (int i = 0; i < 3; i++) {
h_rate[i] = h_ratelo[i] = 0.0;
if (set[i].style == FINAL || set[i].style == DELTA ||
set[i].style == SCALE || set[i].style == VEL ||
set[i].style == ERATE) {
double dlo_dt,dhi_dt;
if (delt != 0.0) {
dlo_dt = (set[i].lo_stop - set[i].lo_start) / delt;
dhi_dt = (set[i].hi_stop - set[i].hi_start) / delt;
} else dlo_dt = dhi_dt = 0.0;
h_rate[i] = dhi_dt - dlo_dt;
h_ratelo[i] = dlo_dt;
}
}
for (int i = 3; i < 6; i++) {
h_rate[i] = 0.0;
if (set[i].style == FINAL || set[i].style == DELTA ||
set[i].style == VEL || set[i].style == ERATE) {
if (delt != 0.0)
h_rate[i] = (set[i].tilt_stop - set[i].tilt_start) / delt;
else h_rate[i] = 0.0;
}
}
// detect if any rigid fixes exist so rigid bodies can be rescaled
// rfix[] = indices to each fix rigid
delete [] rfix;
nrigid = 0;
rfix = NULL;
for (int i = 0; i < modify->nfix; i++)
if (modify->fix[i]->rigid_flag) nrigid++;
if (nrigid) {
rfix = new int[nrigid];
nrigid = 0;
for (int i = 0; i < modify->nfix; i++)
if (modify->fix[i]->rigid_flag) rfix[nrigid++] = i;
}
}
/* ----------------------------------------------------------------------
box flipped on previous step
perform irregular comm to migrate atoms to new procs
reset box tilts for flipped config and create new box in domain
remap to put far-away atoms back into new box
perform irregular on atoms in lamda coords to get atoms to new procs
force reneighboring on next timestep
------------------------------------------------------------------------- */
void FixDeform::pre_exchange()
{
if (flip == 0) return;
domain->yz = set[3].tilt_target = set[3].tilt_flip;
domain->xz = set[4].tilt_target = set[4].tilt_flip;
domain->xy = set[5].tilt_target = set[5].tilt_flip;
domain->set_global_box();
domain->set_local_box();
double **x = atom->x;
int *image = atom->image;
int nlocal = atom->nlocal;
for (int i = 0; i < nlocal; i++) domain->remap(x[i],image[i]);
domain->x2lamda(atom->nlocal);
comm->irregular();
domain->lamda2x(atom->nlocal);
flip = 0;
}
/* ---------------------------------------------------------------------- */
void FixDeform::end_of_step()
{
int i;
double delta = update->ntimestep - update->beginstep;
delta /= update->endstep - update->beginstep;
// set new box size
// for TRATE, set target directly based on current time, also set h_rate
// for WIGGLE, set target directly based on current time, also set h_rate
// for NONE, target is current box size
// for others except VOLUME, target is linear value between start and stop
for (i = 0; i < 3; i++) {
if (set[i].style == TRATE) {
double delt = (update->ntimestep - update->beginstep) * update->dt;
set[i].lo_target = 0.5*(set[i].lo_start+set[i].hi_start) -
0.5*((set[i].hi_start-set[i].lo_start) * exp(set[i].rate*delt));
set[i].hi_target = 0.5*(set[i].lo_start+set[i].hi_start) +
0.5*((set[i].hi_start-set[i].lo_start) * exp(set[i].rate*delt));
h_rate[i] = set[i].rate * domain->h[i];
h_ratelo[i] = -0.5*h_rate[i];
} else if (set[i].style == WIGGLE) {
double delt = (update->ntimestep - update->beginstep) * update->dt;
set[i].lo_target = set[i].lo_start -
0.5*set[i].amplitude * sin(TWOPI*delt/set[i].tperiod);
set[i].hi_target = set[i].hi_start +
0.5*set[i].amplitude * sin(TWOPI*delt/set[i].tperiod);
h_rate[i] = TWOPI/set[i].tperiod * set[i].amplitude *
cos(TWOPI*delt/set[i].tperiod);
h_ratelo[i] = -0.5*h_rate[i];
} else if (set[i].style == NONE) {
set[i].lo_target = domain->boxlo[i];
set[i].hi_target = domain->boxhi[i];
} else if (set[i].style != VOLUME) {
set[i].lo_target = set[i].lo_start +
delta*(set[i].lo_stop - set[i].lo_start);
set[i].hi_target = set[i].hi_start +
delta*(set[i].hi_stop - set[i].hi_start);
}
}
// set new box size for VOLUME dims that are linked to other dims
// NOTE: still need to set h_rate for these dims
for (int i = 0; i < 3; i++) {
if (set[i].style != VOLUME) continue;
if (set[i].substyle == ONE_FROM_ONE) {
set[i].lo_target = 0.5*(set[i].lo_start+set[i].hi_start) -
0.5*(set[i].vol_start /
(set[set[i].dynamic1].hi_target -
set[set[i].dynamic1].lo_target) /
(set[set[i].fixed].hi_start-set[set[i].fixed].lo_start));
set[i].hi_target = 0.5*(set[i].lo_start+set[i].hi_start) +
0.5*(set[i].vol_start /
(set[set[i].dynamic1].hi_target -
set[set[i].dynamic1].lo_target) /
(set[set[i].fixed].hi_start-set[set[i].fixed].lo_start));
} else if (set[i].substyle == ONE_FROM_TWO) {
set[i].lo_target = 0.5*(set[i].lo_start+set[i].hi_start) -
0.5*(set[i].vol_start /
(set[set[i].dynamic1].hi_target -
set[set[i].dynamic1].lo_target) /
(set[set[i].dynamic2].hi_target -
set[set[i].dynamic2].lo_target));
set[i].hi_target = 0.5*(set[i].lo_start+set[i].hi_start) +
0.5*(set[i].vol_start /
(set[set[i].dynamic1].hi_target -
set[set[i].dynamic1].lo_target) /
(set[set[i].dynamic2].hi_target -
set[set[i].dynamic2].lo_target));
} else if (set[i].substyle == TWO_FROM_ONE) {
set[i].lo_target = 0.5*(set[i].lo_start+set[i].hi_start) -
0.5*sqrt(set[i].vol_start /
(set[set[i].dynamic1].hi_target -
set[set[i].dynamic1].lo_target) /
(set[set[i].fixed].hi_start -
set[set[i].fixed].lo_start) *
(set[i].hi_start - set[i].lo_start));
set[i].hi_target = 0.5*(set[i].lo_start+set[i].hi_start) +
0.5*sqrt(set[i].vol_start /
(set[set[i].dynamic1].hi_target -
set[set[i].dynamic1].lo_target) /
(set[set[i].fixed].hi_start -
set[set[i].fixed].lo_start) *
(set[i].hi_start - set[i].lo_start));
}
}
// for triclinic, set new box shape
// for TRATE, set target directly based on current time. also set h_rate
// for WIGGLE, set target directly based on current time. also set h_rate
// for NONE, target is current tilt
// for other styles, target is linear value between start and stop values
if (triclinic) {
double *h = domain->h;
for (i = 3; i < 6; i++) {
if (set[i].style == TRATE) {
double delt = (update->ntimestep - update->beginstep) * update->dt;
set[i].tilt_target = set[i].tilt_start * exp(set[i].rate*delt);
h_rate[i] = set[i].rate * domain->h[i];
} else if (set[i].style == WIGGLE) {
double delt = (update->ntimestep - update->beginstep) * update->dt;
set[i].tilt_target = set[i].tilt_start +
set[i].amplitude * sin(TWOPI*delt/set[i].tperiod);
h_rate[i] = TWOPI/set[i].tperiod * set[i].amplitude *
cos(TWOPI*delt/set[i].tperiod);
} else if (set[i].style == NONE) {
if (i == 5) set[i].tilt_target = domain->xy;
else if (i == 4) set[i].tilt_target = domain->xz;
else if (i == 3) set[i].tilt_target = domain->yz;
} else {
set[i].tilt_target = set[i].tilt_start +
delta*(set[i].tilt_stop - set[i].tilt_start);
}
// tilt_target can be large positive or large negative value
// add/subtract box lengths until tilt_target is closest to current value
int idenom;
if (i == 5) idenom = 0;
else if (i == 4) idenom = 0;
else if (i == 3) idenom = 1;
double denom = set[idenom].hi_target - set[idenom].lo_target;
double current = h[i]/h[idenom];
while (set[i].tilt_target/denom - current > 0.0)
set[i].tilt_target -= denom;
while (set[i].tilt_target/denom - current < 0.0)
set[i].tilt_target += denom;
if (fabs(set[i].tilt_target/denom - 1.0 - current) <
fabs(set[i].tilt_target/denom - current))
set[i].tilt_target -= denom;
}
}
// if any tilt targets exceed bounds, set flip flag and new tilt_flip values
// flip will be performed on next timestep before reneighboring
// when yz flips and xy is non-zero, xz must also change
// this is to keep the edge vectors of the flipped shape matrix
// a linear combination of the edge vectors of the unflipped shape matrix
if (triclinic) {
double xprd = set[0].hi_target - set[0].lo_target;
double yprd = set[1].hi_target - set[1].lo_target;
if (set[3].tilt_target < -0.5*yprd || set[3].tilt_target > 0.5*yprd ||
set[4].tilt_target < -0.5*xprd || set[4].tilt_target > 0.5*xprd ||
set[5].tilt_target < -0.5*xprd || set[5].tilt_target > 0.5*xprd) {
flip = 1;
next_reneighbor = update->ntimestep + 1;
set[3].tilt_flip = set[3].tilt_target;
set[4].tilt_flip = set[4].tilt_target;
set[5].tilt_flip = set[5].tilt_target;
if (set[3].tilt_flip < -0.5*yprd) {
set[3].tilt_flip += yprd;
set[4].tilt_flip += set[5].tilt_flip;
} else if (set[3].tilt_flip >= 0.5*yprd) {
set[3].tilt_flip -= yprd;
set[4].tilt_flip -= set[5].tilt_flip;
}
if (set[4].tilt_flip < -0.5*xprd) set[4].tilt_flip += xprd;
if (set[4].tilt_flip > 0.5*xprd) set[4].tilt_flip -= xprd;
if (set[5].tilt_flip < -0.5*xprd) set[5].tilt_flip += xprd;
if (set[5].tilt_flip > 0.5*xprd) set[5].tilt_flip -= xprd;
}
}
// convert atoms and rigid bodies to lamda coords
if (remapflag == X_REMAP) {
double **x = atom->x;
int *mask = atom->mask;
int nlocal = atom->nlocal;
for (i = 0; i < nlocal; i++)
if (mask[i] & groupbit)
domain->x2lamda(x[i],x[i]);
if (nrigid)
for (i = 0; i < nrigid; i++)
modify->fix[rfix[i]]->deform(0);
}
// reset global and local box to new size/shape
// only if deform fix is controlling the dimension
if (set[0].style) {
domain->boxlo[0] = set[0].lo_target;
domain->boxhi[0] = set[0].hi_target;
}
if (set[1].style) {
domain->boxlo[1] = set[1].lo_target;
domain->boxhi[1] = set[1].hi_target;
}
if (set[2].style) {
domain->boxlo[2] = set[2].lo_target;
domain->boxhi[2] = set[2].hi_target;
}
if (triclinic) {
if (set[3].style) domain->yz = set[3].tilt_target;
if (set[4].style) domain->xz = set[4].tilt_target;
if (set[5].style) domain->xy = set[5].tilt_target;
}
domain->set_global_box();
domain->set_local_box();
// convert atoms and rigid bodies back to box coords
if (remapflag == X_REMAP) {
double **x = atom->x;
int *mask = atom->mask;
int nlocal = atom->nlocal;
for (i = 0; i < nlocal; i++)
if (mask[i] & groupbit)
domain->lamda2x(x[i],x[i]);
if (nrigid)
for (i = 0; i < nrigid; i++)
modify->fix[rfix[i]]->deform(1);
}
// redo KSpace coeffs since box has changed
if (kspace_flag) force->kspace->setup();
}
/* ---------------------------------------------------------------------- */
void FixDeform::options(int narg, char **arg)
{
if (narg < 0) error->all("Illegal fix deform command");
remapflag = X_REMAP;
scaleflag = 1;
int iarg = 0;
while (iarg < narg) {
if (strcmp(arg[iarg],"remap") == 0) {
if (iarg+2 > narg) error->all("Illegal fix deform command");
if (strcmp(arg[iarg+1],"x") == 0) remapflag = X_REMAP;
else if (strcmp(arg[iarg+1],"v") == 0) remapflag = V_REMAP;
else if (strcmp(arg[iarg+1],"none") == 0) remapflag = NO_REMAP;
else error->all("Illegal fix deform command");
iarg += 2;
} else if (strcmp(arg[iarg],"units") == 0) {
if (iarg+2 > narg) error->all("Illegal fix deform command");
if (strcmp(arg[iarg+1],"box") == 0) scaleflag = 0;
else if (strcmp(arg[iarg+1],"lattice") == 0) scaleflag = 1;
else error->all("Illegal fix deform command");
iarg += 2;
} else error->all("Illegal fix deform command");
}
}

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