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fix_lb_rigid_pc_sphere.cpp
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Mon, Nov 11, 22:05

fix_lb_rigid_pc_sphere.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 authors: Frances Mackay, Santtu Ollila, Colin Denniston (UWO)
Based on fix_rigid (version from 2008).
------------------------------------------------------------------------- */
#include "math.h"
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "fix_lb_rigid_pc_sphere.h"
#include "atom.h"
#include "atom_vec.h"
#include "domain.h"
#include "update.h"
#include "respa.h"
#include "modify.h"
#include "group.h"
#include "comm.h"
#include "force.h"
#include "output.h"
#include "memory.h"
#include "error.h"
#include "fix_lb_fluid.h"
using namespace LAMMPS_NS;
using namespace FixConst;
/* -------------------------------------------------------------------------- */
FixLbRigidPCSphere::FixLbRigidPCSphere(LAMMPS *lmp, int narg, char **arg) :
Fix(lmp, narg, arg)
{
int i, ibody;
scalar_flag = 1;
extscalar = 0;
time_integrate = 1;
rigid_flag = 1;
create_attribute = 1;
virial_flag = 1;
// perform initial allocation of atom-based arrays
// register with Atom class
body = NULL;
up = NULL;
grow_arrays(atom->nmax);
atom->add_callback(0);
// by default assume all of the particles interact with the fluid.
inner_nodes = 0;
// parse command-line args
// set nbody and body[i] for each atom
if (narg < 4) error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
// single rigid body
// nbody = 1
// all atoms in fix group are part of body
int iarg;
if (strcmp(arg[3],"single") == 0) {
iarg = 4;
nbody = 1;
int *mask = atom->mask;
int nlocal = atom->nlocal;
for (i = 0; i < nlocal; i++) {
body[i] = -1;
if (mask[i] & groupbit) body[i] = 0;
}
// each molecule in fix group is a rigid body
// maxmol = largest molecule #
// ncount = # of atoms in each molecule (have to sum across procs)
// nbody = # of non-zero ncount values
// use nall as incremented ptr to set body[] values for each atom
} else if (strcmp(arg[3],"molecule") == 0) {
iarg = 4;
if (atom->molecular == 0)
error->all(FLERR,"Must use a molecular atom style with "
"fix lb/rigid/pc/sphere molecule");
int *mask = atom->mask;
tagint *molecule = atom->molecule;
int nlocal = atom->nlocal;
tagint maxmol_tag = -1;
for (i = 0; i < nlocal; i++)
if (mask[i] & groupbit) maxmol_tag = MAX(maxmol_tag,molecule[i]);
tagint itmp;
MPI_Allreduce(&maxmol_tag,&itmp,1,MPI_LMP_TAGINT,MPI_MAX,world);
if (itmp+1 > MAXSMALLINT)
error->all(FLERR,"Too many molecules for fix lb/rigid/pc/sphere");
int maxmol = (int) itmp;
int *ncount;
memory->create(ncount,maxmol+1,"rigid:ncount");
for (i = 0; i <= maxmol; i++) ncount[i] = 0;
for (i = 0; i < nlocal; i++)
if (mask[i] & groupbit) ncount[molecule[i]]++;
int *nall;
memory->create(nall,maxmol+1,"rigid:ncount");
MPI_Allreduce(ncount,nall,maxmol+1,MPI_LMP_TAGINT,MPI_SUM,world);
nbody = 0;
for (i = 0; i <= maxmol; i++)
if (nall[i]) nall[i] = nbody++;
else nall[i] = -1;
for (i = 0; i < nlocal; i++) {
body[i] = -1;
if (mask[i] & groupbit) body[i] = nall[molecule[i]];
}
memory->destroy(ncount);
memory->destroy(nall);
// each listed group is a rigid body
// check if all listed groups exist
// an atom must belong to fix group and listed group to be in rigid body
// error if atom belongs to more than 1 rigid body
} else if (strcmp(arg[3],"group") == 0) {
if (narg < 5) error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
nbody = atoi(arg[4]);
if (nbody <= 0) error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
if (narg < 5+nbody)
error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
iarg = 5 + nbody;
int *igroups = new int[nbody];
for (ibody = 0; ibody < nbody; ibody++) {
igroups[ibody] = group->find(arg[5+ibody]);
if (igroups[ibody] == -1)
error->all(FLERR,"Could not find fix lb/rigid/pc/sphere group ID");
}
int *mask = atom->mask;
int nlocal = atom->nlocal;
int flag = 0;
for (i = 0; i < nlocal; i++) {
body[i] = -1;
if (mask[i] & groupbit)
for (ibody = 0; ibody < nbody; ibody++)
if (mask[i] & group->bitmask[igroups[ibody]]) {
if (body[i] >= 0) flag = 1;
body[i] = ibody;
}
}
int flagall;
MPI_Allreduce(&flag,&flagall,1,MPI_INT,MPI_SUM,world);
if (flagall)
error->all(FLERR,"One or more atoms belong to multiple rigid bodies");
delete [] igroups;
}else error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
// error check on nbody
if (nbody == 0) error->all(FLERR,"No rigid bodies defined");
// create all nbody-length arrays
memory->create(nrigid,nbody,"lb/rigid/pc/sphere:nrigid");
memory->create(nrigid_shell,nbody,"lb/rigid/pc/sphere:nrigid_shell");
memory->create(masstotal,nbody,"lb/rigid/pc/sphere:masstotal");
memory->create(masstotal_shell,nbody,"lb/rigid/pc/sphere:masstotal_shell");
memory->create(sphereradius,nbody,"lb/rigid/pc/sphere:sphereradius");
memory->create(xcm,nbody,3,"lb/rigid/pc/sphere:xcm");
memory->create(xcm_old,nbody,3,"lb/rigid/pc/sphere:xcm_old");
memory->create(vcm,nbody,3,"lb/rigid/pc/sphere:vcm");
memory->create(ucm,nbody,3,"lb/rigid/pc/sphere:ucm");
memory->create(ucm_old,nbody,3,"lb/rigid/pc/sphere:ucm_old");
memory->create(fcm,nbody,3,"lb/rigid/pc/sphere:fcm");
memory->create(fcm_old,nbody,3,"lb/rigid/pc/sphere:fcm_old");
memory->create(fcm_fluid,nbody,3,"lb/rigid/pc/sphere:fcm_fluid");
memory->create(omega,nbody,3,"lb/rigid/pc/sphere:omega");
memory->create(torque,nbody,3,"lb/rigid/pc/sphere:torque");
memory->create(torque_old,nbody,3,"lb/rigid/pc/sphere:torque_old");
memory->create(torque_fluid,nbody,3,"lb/rigid/pc/sphere:torque_fluid");
memory->create(torque_fluid_old,nbody,3,"lb/rigid/pc/sphere:torque_fluid_old");
memory->create(rotate,nbody,3,"lb/rigid/pc/sphere:rotate");
memory->create(imagebody,nbody,"lb/rigid/pc/sphere:imagebody");
memory->create(fflag,nbody,3,"lb/rigid/pc/sphere:fflag");
memory->create(tflag,nbody,3,"lb/rigid/pc/sphere:tflag");
memory->create(sum,nbody,6,"lb/rigid/pc/sphere:sum");
memory->create(all,nbody,6,"lb/rigid/pc/sphere:all");
memory->create(remapflag,nbody,4,"lb/rigid/pc/sphere:remapflag");
Gamma_MD = new double[nbody];
// initialize force/torque flags to default = 1.0
array_flag = 1;
size_array_rows = nbody;
size_array_cols = 15;
global_freq = 1;
extarray = 0;
for (i = 0; i < nbody; i++) {
fflag[i][0] = fflag[i][1] = fflag[i][2] = 1.0;
tflag[i][0] = tflag[i][1] = tflag[i][2] = 1.0;
}
// parse optional args that set fflag and tflag
while (iarg < narg) {
if (strcmp(arg[iarg],"force") == 0) {
if (iarg+5 > narg) error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
int mlo,mhi;
force->bounds(arg[iarg+1],nbody,mlo,mhi);
double xflag,yflag,zflag;
if (strcmp(arg[iarg+2],"off") == 0) xflag = 0.0;
else if (strcmp(arg[iarg+2],"on") == 0) xflag = 1.0;
else error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
if (strcmp(arg[iarg+2],"off") == 0) yflag = 0.0;
else if (strcmp(arg[iarg+3],"on") == 0) yflag = 1.0;
else error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
if (strcmp(arg[iarg+4],"off") == 0) zflag = 0.0;
else if (strcmp(arg[iarg+4],"on") == 0) zflag = 1.0;
else error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
int count = 0;
for (int m = mlo; m <= mhi; m++) {
fflag[m-1][0] = xflag;
fflag[m-1][1] = yflag;
fflag[m-1][2] = zflag;
count++;
}
if (count == 0) error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
iarg += 5;
} else if (strcmp(arg[iarg],"torque") == 0) {
if (iarg+5 > narg) error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
int mlo,mhi;
force->bounds(arg[iarg+1],nbody,mlo,mhi);
double xflag,yflag,zflag;
if (strcmp(arg[iarg+2],"off") == 0) xflag = 0.0;
else if (strcmp(arg[iarg+2],"on") == 0) xflag = 1.0;
else error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
if (strcmp(arg[iarg+3],"off") == 0) yflag = 0.0;
else if (strcmp(arg[iarg+3],"on") == 0) yflag = 1.0;
else error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
if (strcmp(arg[iarg+4],"off") == 0) zflag = 0.0;
else if (strcmp(arg[iarg+4],"on") == 0) zflag = 1.0;
else error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
int count = 0;
for (int m = mlo; m <= mhi; m++) {
tflag[m-1][0] = xflag;
tflag[m-1][1] = yflag;
tflag[m-1][2] = zflag;
count++;
}
if (count == 0) error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
iarg += 5;
// specify if certain particles are inside the rigid spherical body,
// and therefore should not
} else if(strcmp(arg[iarg],"innerNodes")==0){
inner_nodes = 1;
igroupinner = group->find(arg[iarg+1]);
if(igroupinner == -1)
error->all(FLERR,"Could not find fix lb/rigid/pc/sphere innerNodes group ID");
iarg += 2;
} else error->all(FLERR,"Illegal fix lb/rigid/pc/sphere command");
}
// initialize vector output quantities in case accessed before run
for (i = 0; i < nbody; i++) {
xcm[i][0] = xcm[i][1] = xcm[i][2] = 0.0;
xcm_old[i][0] = xcm_old[i][1] = xcm_old[i][2] = 0.0;
vcm[i][0] = vcm[i][1] = vcm[i][2] = 0.0;
ucm[i][0] = ucm[i][1] = ucm[i][2] = 0.0;
ucm_old[i][0] = ucm_old[i][1] = ucm_old[i][2] = 0.0;
fcm[i][0] = fcm[i][1] = fcm[i][2] = 0.0;
fcm_old[i][0] = fcm_old[i][1] = fcm_old[i][2] = 0.0;
fcm_fluid[i][0] = fcm_fluid[i][1] = fcm_fluid[i][2] = 0.0;
torque[i][0] = torque[i][1] = torque[i][2] = 0.0;
torque_old[i][0] = torque_old[i][1] = torque_old[i][2] = 0.0;
torque_fluid[i][0] = torque_fluid[i][1] = torque_fluid[i][2] = 0.0;
torque_fluid_old[i][0] = torque_fluid_old[i][1] = torque_fluid_old[i][2] = 0.0;
}
// nrigid[n] = # of atoms in Nth rigid body
// error if one or zero atoms
int *ncount = new int[nbody];
for (ibody = 0; ibody < nbody; ibody++) ncount[ibody] = 0;
int nlocal = atom->nlocal;
for (i = 0; i < nlocal; i++)
if (body[i] >= 0) ncount[body[i]]++;
MPI_Allreduce(ncount,nrigid,nbody,MPI_INT,MPI_SUM,world);
//count the number of atoms in the shell.
if(inner_nodes == 1){
int *mask = atom->mask;
for(ibody=0; ibody<nbody; ibody++) ncount[ibody] = 0;
for(i=0; i<nlocal; i++){
if(!(mask[i] & group->bitmask[igroupinner])){
if(body[i] >= 0) ncount[body[i]]++;
}
}
MPI_Allreduce(ncount,nrigid_shell,nbody,MPI_INT,MPI_SUM,world);
}else {
for(ibody=0; ibody < nbody; ibody++) nrigid_shell[ibody]=nrigid[ibody];
}
delete [] ncount;
for (ibody = 0; ibody < nbody; ibody++)
if (nrigid[ibody] <= 1) error->all(FLERR,"One or zero atoms in rigid body");
// set image flags for each rigid body to default values
// will be reset during init() based on xcm and then by pre_neighbor()
// set here, so image value will persist from run to run
for (ibody = 0; ibody < nbody; ibody++)
imagebody[ibody] = ((imageint) IMGMAX << IMG2BITS) |
((imageint) IMGMAX << IMGBITS) | IMGMAX;
// print statistics
int nsum = 0;
for (ibody = 0; ibody < nbody; ibody++) nsum += nrigid[ibody];
if (comm->me == 0) {
if (screen) fprintf(screen,"%d rigid bodies with %d atoms\n",nbody,nsum);
if (logfile) fprintf(logfile,"%d rigid bodies with %d atoms\n",nbody,nsum);
}
int groupbit_lb_fluid = 0;
for(int ifix=0; ifix<modify->nfix; ifix++)
if(strcmp(modify->fix[ifix]->style,"lb/fluid")==0){
fix_lb_fluid = (FixLbFluid *)modify->fix[ifix];
groupbit_lb_fluid = group->bitmask[modify->fix[ifix]->igroup];
}
if(groupbit_lb_fluid == 0)
error->all(FLERR,"the lb/fluid fix must also be used if using the lb/rigid/pc/sphere fix");
int *mask = atom->mask;
if(inner_nodes == 1){
for(int j=0; j<nlocal; j++){
if((mask[j] & groupbit) && !(mask[j] & group->bitmask[igroupinner]) && !(mask[j] & groupbit_lb_fluid))
error->one(FLERR,"use the innerNodes keyword in the lb/rigid/pc/sphere fix for atoms which do not interact with the lb/fluid");
// If inner nodes are present, which should not interact with the fluid, make
// sure these are not used by the lb/fluid fix to apply a force to the fluid.
if((mask[j] & groupbit) && (mask[j] & groupbit_lb_fluid) && (mask[j] & group->bitmask[igroupinner]))
error->one(FLERR,"the inner nodes specified in lb/rigid/pc/sphere should not be included in the lb/fluid fix");
}
}else{
for(int j=0; j<nlocal; j++){
if((mask[j] & groupbit) && !(mask[j] & groupbit_lb_fluid))
error->one(FLERR,"use the innerNodes keyword in the lb/rigid/pc/sphere fix for atoms which do not interact with the lb/fluid");
}
}
}
/* ---------------------------------------------------------------------- */
FixLbRigidPCSphere::~FixLbRigidPCSphere()
{
// unregister callbacks to this fix from Atom class
atom->delete_callback(id,0);
// delete locally stored arrays
memory->destroy(body);
memory->destroy(up);
// delete nbody-length arrays
memory->destroy(nrigid);
memory->destroy(nrigid_shell);
memory->destroy(masstotal);
memory->destroy(masstotal_shell);
memory->destroy(sphereradius);
memory->destroy(xcm);
memory->destroy(xcm_old);
memory->destroy(vcm);
memory->destroy(ucm);
memory->destroy(ucm_old);
memory->destroy(fcm);
memory->destroy(fcm_old);
memory->destroy(fcm_fluid);
memory->destroy(omega);
memory->destroy(torque);
memory->destroy(torque_old);
memory->destroy(torque_fluid);
memory->destroy(torque_fluid_old);
memory->destroy(rotate);
memory->destroy(imagebody);
memory->destroy(fflag);
memory->destroy(tflag);
memory->destroy(sum);
memory->destroy(all);
memory->destroy(remapflag);
delete [] Gamma_MD;
}
/* ---------------------------------------------------------------------- */
int FixLbRigidPCSphere::setmask()
{
int mask = 0;
mask |= INITIAL_INTEGRATE;
mask |= FINAL_INTEGRATE;
mask |= PRE_NEIGHBOR;
return mask;
}
/* ---------------------------------------------------------------------- */
void FixLbRigidPCSphere::init()
{
int i,ibody;
// warn if more than one rigid fix
int count = 0;
for (int i = 0; i < modify->nfix; i++)
if (strcmp(modify->fix[i]->style,"lb/rigid/pc/sphere") == 0) count++;
if (count > 1 && comm->me == 0) error->warning(FLERR,"More than one fix lb/rigid/pc/sphere");
// timestep info
dtv = update->dt;
dtf = 0.5 * update->dt * force->ftm2v;
int *type = atom->type;
int nlocal = atom->nlocal;
double **x = atom->x;
imageint *image = atom->image;
double *rmass = atom->rmass;
double *mass = atom->mass;
int *periodicity = domain->periodicity;
double xprd = domain->xprd;
double yprd = domain->yprd;
double zprd = domain->zprd;
double **mu = atom->mu;
double *radius = atom->radius;
int *ellipsoid = atom->ellipsoid;
int extended = 0;
int *mask = atom->mask;
// Warn if any extended particles are included.
if (atom->radius_flag || atom->ellipsoid_flag || atom->mu_flag) {
int flag = 0;
for (i = 0; i < nlocal; i++) {
if (body[i] < 0) continue;
if (radius && radius[i] > 0.0) flag = 1;
if (ellipsoid && ellipsoid[i] >= 0) flag = 1;
if (mu && mu[i][3] > 0.0) flag = 1;
}
MPI_Allreduce(&flag,&extended,1,MPI_INT,MPI_MAX,world);
}
if(extended)
error->warning(FLERR,"Fix lb/rigid/pc/sphere assumes point particles");
// compute masstotal & center-of-mass of each rigid body
for (ibody = 0; ibody < nbody; ibody++)
for (i = 0; i < 6; i++) sum[ibody][i] = 0.0;
int xbox,ybox,zbox;
double massone,xunwrap,yunwrap,zunwrap;
for (i = 0; i < nlocal; i++) {
if (body[i] < 0) continue;
ibody = body[i];
xbox = (image[i] & IMGMASK) - IMGMAX;
ybox = (image[i] >> IMGBITS & IMGMASK) - IMGMAX;
zbox = (image[i] >> IMG2BITS) - IMGMAX;
if (rmass) massone = rmass[i];
else massone = mass[type[i]];
if ((xbox && !periodicity[0]) || (ybox && !periodicity[1]) ||
(zbox && !periodicity[2]))
error->one(FLERR,"Fix lb/rigid/pc/sphere atom has non-zero image flag "
"in a non-periodic dimension");
xunwrap = x[i][0] + xbox*xprd;
yunwrap = x[i][1] + ybox*yprd;
zunwrap = x[i][2] + zbox*zprd;
sum[ibody][0] += xunwrap * massone;
sum[ibody][1] += yunwrap * massone;
sum[ibody][2] += zunwrap * massone;
sum[ibody][3] += massone;
if(inner_nodes == 1){
if(!(mask[i] & group->bitmask[igroupinner])){
sum[ibody][4] += massone;
}
}else{
sum[ibody][4] += massone;
}
}
MPI_Allreduce(sum[0],all[0],6*nbody,MPI_DOUBLE,MPI_SUM,world);
for (ibody = 0; ibody < nbody; ibody++) {
masstotal[ibody] = all[ibody][3];
masstotal_shell[ibody] = all[ibody][4];
xcm[ibody][0] = all[ibody][0]/masstotal[ibody];
xcm[ibody][1] = all[ibody][1]/masstotal[ibody];
xcm[ibody][2] = all[ibody][2]/masstotal[ibody];
}
// Calculate the radius of the rigid body, and assign the value for gamma:
double dx,dy,dz;
double *Gamma = fix_lb_fluid->Gamma;
double dm_lb = fix_lb_fluid->dm_lb;
double dt_lb = fix_lb_fluid->dt_lb;
for (ibody = 0; ibody < nbody; ibody++)
for (i = 0; i < 6; i++) sum[ibody][i] = 0.0;
for (i=0; i<nlocal; i++){
if(body[i] < 0) continue;
if(inner_nodes == 1){
if(!(mask[i] & group->bitmask[igroupinner])){
ibody = body[i];
xbox = (image[i] & IMGMASK) - IMGMAX;
ybox = (image[i] >> IMGBITS & IMGMASK) - IMGMAX;
zbox = (image[i] >> IMG2BITS) - IMGMAX;
xunwrap = x[i][0] + xbox*xprd;
yunwrap = x[i][1] + ybox*yprd;
zunwrap = x[i][2] + zbox*zprd;
dx = xunwrap - xcm[ibody][0];
dy = yunwrap - xcm[ibody][1];
dz = zunwrap - xcm[ibody][2];
sum[ibody][0] += dx*dx + dy*dy + dz*dz;
sum[ibody][1] += Gamma[type[i]];
}
}else{
ibody = body[i];
xbox = (image[i] & IMGMASK) - IMGMAX;
ybox = (image[i] >> IMGBITS & IMGMASK) - IMGMAX;
zbox = (image[i] >> IMG2BITS) - IMGMAX;
xunwrap = x[i][0] + xbox*xprd;
yunwrap = x[i][1] + ybox*yprd;
zunwrap = x[i][2] + zbox*zprd;
dx = xunwrap - xcm[ibody][0];
dy = yunwrap - xcm[ibody][1];
dz = zunwrap - xcm[ibody][2];
sum[ibody][0] += dx*dx + dy*dy + dz*dz;
sum[ibody][1] += Gamma[type[i]];
}
}
MPI_Allreduce(sum[0],all[0],6*nbody,MPI_DOUBLE,MPI_SUM,world);
for(ibody=0; ibody < nbody; ibody++){
sphereradius[ibody] = sqrt(all[ibody][0]/nrigid_shell[ibody]);
Gamma_MD[ibody] = all[ibody][1]*dm_lb/dt_lb/nrigid_shell[ibody];
}
// Check that all atoms in the rigid body have the same value of gamma.
double eps = 1.0e-7;
for (i=0; i<nlocal; i++){
if(body[i] < 0) continue;
if(inner_nodes == 1){
if(!(mask[i] & group->bitmask[igroupinner])){
ibody = body[i];
if(Gamma_MD[ibody]*dt_lb/dm_lb - Gamma[type[i]] > eps)
error->one(FLERR,"All atoms in a rigid body must have the same gamma value");
}
}else{
ibody = body[i];
if(Gamma_MD[ibody]*dt_lb/dm_lb - Gamma[type[i]] > eps)
error->one(FLERR,"All atoms in a rigid body must have the same gamma value");
}
}
// remap the xcm of each body back into simulation box if needed
// only really necessary the 1st time a run is performed
pre_neighbor();
// temperature scale factor
double ndof = 0.0;
for (ibody = 0; ibody < nbody; ibody++) {
ndof += fflag[ibody][0] + fflag[ibody][1] + fflag[ibody][2];
ndof += tflag[ibody][0] + tflag[ibody][1] + tflag[ibody][2];
}
if (ndof > 0.0) tfactor = force->mvv2e / (ndof * force->boltz);
else tfactor = 0.0;
}
/* ---------------------------------------------------------------------- */
void FixLbRigidPCSphere::setup(int vflag)
{
int i,n,ibody;
double massone;
// vcm = velocity of center-of-mass of each rigid body
// fcm = force on center-of-mass of each rigid body
double **x = atom->x;
double **v = atom->v;
double **f = atom->f;
double *rmass = atom->rmass;
double *mass = atom->mass;
int *type = atom->type;
int nlocal = atom->nlocal;
imageint *image = atom->image;
double unwrap[3];
double dx,dy,dz;
for (ibody = 0; ibody < nbody; ibody++)
for (i = 0; i < 6; i++) sum[ibody][i] = 0.0;
for (i = 0; i < nlocal; i++) {
if (body[i] < 0) continue;
ibody = body[i];
if (rmass) massone = rmass[i];
else massone = mass[type[i]];
sum[ibody][0] += v[i][0] * massone;
sum[ibody][1] += v[i][1] * massone;
sum[ibody][2] += v[i][2] * massone;
sum[ibody][3] += f[i][0];
sum[ibody][4] += f[i][1];
sum[ibody][5] += f[i][2];
}
MPI_Allreduce(sum[0],all[0],6*nbody,MPI_DOUBLE,MPI_SUM,world);
for (ibody = 0; ibody < nbody; ibody++) {
vcm[ibody][0] = all[ibody][0]/masstotal[ibody];
vcm[ibody][1] = all[ibody][1]/masstotal[ibody];
vcm[ibody][2] = all[ibody][2]/masstotal[ibody];
fcm[ibody][0] = all[ibody][3];
fcm[ibody][1] = all[ibody][4];
fcm[ibody][2] = all[ibody][5];
}
// omega = angular velocity of each rigid body
// Calculated as the average of the angular velocities of the
// individual atoms comprising the rigid body.
// torque = torque on each rigid body
for (ibody = 0; ibody < nbody; ibody++)
for (i = 0; i < 6; i++) sum[ibody][i] = 0.0;
for (i = 0; i < nlocal; i++) {
if (body[i] < 0) continue;
ibody = body[i];
domain->unmap(x[i],image[i],unwrap);
dx = unwrap[0] - xcm[ibody][0];
dy = unwrap[1] - xcm[ibody][1];
dz = unwrap[2] - xcm[ibody][2];
if (rmass) massone = rmass[i];
else massone = mass[type[i]];
sum[ibody][0] += (dy * (v[i][2]-vcm[ibody][2]) - dz * (v[i][1]-vcm[ibody][1]))/(dx*dx+dy*dy+dz*dz);
sum[ibody][1] += (dz * (v[i][0]-vcm[ibody][0]) - dx * (v[i][2]-vcm[ibody][2]))/(dx*dx+dy*dy+dz*dz);
sum[ibody][2] += (dx * (v[i][1]-vcm[ibody][1]) - dy * (v[i][0]-vcm[ibody][0]))/(dx*dx+dy*dy+dz*dz);
sum[ibody][3] += dy * f[i][2] - dz * f[i][1];
sum[ibody][4] += dz * f[i][0] - dx * f[i][2];
sum[ibody][5] += dx * f[i][1] - dy * f[i][0];
}
MPI_Allreduce(sum[0],all[0],6*nbody,MPI_DOUBLE,MPI_SUM,world);
for (ibody = 0; ibody < nbody; ibody++) {
omega[ibody][0] = all[ibody][0]/nrigid[ibody];
omega[ibody][1] = all[ibody][1]/nrigid[ibody];
omega[ibody][2] = all[ibody][2]/nrigid[ibody];
torque[ibody][0] = all[ibody][3];
torque[ibody][1] = all[ibody][4];
torque[ibody][2] = all[ibody][5];
}
// virial setup before call to set_v
if (vflag) v_setup(vflag);
else evflag = 0;
// Set the velocities
set_v();
if (vflag_global)
for (n = 0; n < 6; n++) virial[n] *= 2.0;
if (vflag_atom) {
for (i = 0; i < nlocal; i++)
for (n = 0; n < 6; n++)
vatom[i][n] *= 2.0;
}
}
/* ---------------------------------------------------------------------- */
void FixLbRigidPCSphere::initial_integrate(int vflag)
{
double dtfm;
int i,ibody;
double massone;
double **x = atom->x;
double **v = atom->v;
double *rmass = atom->rmass;
double *mass = atom->mass;
int *type = atom->type;
int nlocal = atom->nlocal;
imageint *image = atom->image;
double unwrap[3];
double dx,dy,dz;
int *mask = atom->mask;
// compute the fluid velocity at the initial particle positions
compute_up();
for (ibody = 0; ibody < nbody; ibody++)
for (i = 0; i < 6; i++) sum[ibody][i] = 0.0;
// Store the fluid velocity at the center of mass
for (i = 0; i < nlocal; i++) {
if (body[i] < 0) continue;
ibody = body[i];
if (rmass) massone = rmass[i];
else massone = mass[type[i]];
if(inner_nodes == 1){
if(!(mask[i] & group->bitmask[igroupinner])){
sum[ibody][0] += up[i][0]*massone;
sum[ibody][1] += up[i][1]*massone;
sum[ibody][2] += up[i][2]*massone;
}
}else{
sum[ibody][0] += up[i][0]*massone;
sum[ibody][1] += up[i][1]*massone;
sum[ibody][2] += up[i][2]*massone;
}
}
MPI_Allreduce(sum[0],all[0],6*nbody,MPI_DOUBLE,MPI_SUM,world);
for (ibody = 0; ibody < nbody; ibody++) {
ucm[ibody][0] = all[ibody][0]/masstotal_shell[ibody];
ucm[ibody][1] = all[ibody][1]/masstotal_shell[ibody];
ucm[ibody][2] = all[ibody][2]/masstotal_shell[ibody];
}
//Store the total torque due to the fluid.
for (ibody = 0; ibody < nbody; ibody++)
for(i = 0; i < 6; i++) sum[ibody][i] = 0.0;
for(i = 0; i<nlocal; i++){
if(body[i] < 0) continue;
ibody = body[i];
domain->unmap(x[i],image[i],unwrap);
dx = unwrap[0] - xcm[ibody][0];
dy = unwrap[1] - xcm[ibody][1];
dz = unwrap[2] - xcm[ibody][2];
if (rmass) massone = rmass[i];
else massone = mass[type[i]];
if(inner_nodes == 1){
if(!(mask[i] & group->bitmask[igroupinner])){
sum[ibody][0] += Gamma_MD[ibody]*(dy * ((up[i][2]-vcm[ibody][2])) -
dz * ((up[i][1]-vcm[ibody][1])));
sum[ibody][1] += Gamma_MD[ibody]*(dz * ((up[i][0]-vcm[ibody][0])) -
dx * ((up[i][2]-vcm[ibody][2])));
sum[ibody][2] += Gamma_MD[ibody]*(dx * ((up[i][1]-vcm[ibody][1])) -
dy * ((up[i][0]-vcm[ibody][0])));
sum[ibody][3] += -Gamma_MD[ibody]*(v[i][0]-up[i][0]);
sum[ibody][4] += -Gamma_MD[ibody]*(v[i][1]-up[i][1]);
sum[ibody][5] += -Gamma_MD[ibody]*(v[i][2]-up[i][2]);
}
}else{
sum[ibody][0] += Gamma_MD[ibody]*(dy * ((up[i][2]-vcm[ibody][2])) -
dz * ((up[i][1]-vcm[ibody][1])));
sum[ibody][1] += Gamma_MD[ibody]*(dz * ((up[i][0]-vcm[ibody][0])) -
dx * ((up[i][2]-vcm[ibody][2])));
sum[ibody][2] += Gamma_MD[ibody]*(dx * ((up[i][1]-vcm[ibody][1])) -
dy * ((up[i][0]-vcm[ibody][0])));
sum[ibody][3] += -Gamma_MD[ibody]*(v[i][0]-up[i][0]);
sum[ibody][4] += -Gamma_MD[ibody]*(v[i][1]-up[i][1]);
sum[ibody][5] += -Gamma_MD[ibody]*(v[i][2]-up[i][2]);
}
}
MPI_Allreduce(sum[0],all[0],6*nbody,MPI_DOUBLE,MPI_SUM,world);
for (ibody = 0; ibody < nbody; ibody++) {
torque_fluid[ibody][0] = all[ibody][0];
torque_fluid[ibody][1] = all[ibody][1];
torque_fluid[ibody][2] = all[ibody][2];
fcm_fluid[ibody][0] = all[ibody][3];
fcm_fluid[ibody][1] = all[ibody][4];
fcm_fluid[ibody][2] = all[ibody][5];
}
for (int ibody = 0; ibody < nbody; ibody++) {
fcm_old[ibody][0] = fcm[ibody][0];
fcm_old[ibody][1] = fcm[ibody][1];
fcm_old[ibody][2] = fcm[ibody][2];
torque_old[ibody][0] = torque[ibody][0];
torque_old[ibody][1] = torque[ibody][1];
torque_old[ibody][2] = torque[ibody][2];
torque_fluid_old[ibody][0] = torque_fluid[ibody][0];
torque_fluid_old[ibody][1] = torque_fluid[ibody][1];
torque_fluid_old[ibody][2] = torque_fluid[ibody][2];
ucm_old[ibody][0] = ucm[ibody][0];
ucm_old[ibody][1] = ucm[ibody][1];
ucm_old[ibody][2] = ucm[ibody][2];
xcm_old[ibody][0] = xcm[ibody][0];
xcm_old[ibody][1] = xcm[ibody][1];
xcm_old[ibody][2] = xcm[ibody][2];
// update xcm by full step
dtfm = dtf / masstotal[ibody];
xcm[ibody][0] += dtv * vcm[ibody][0]+(fcm[ibody][0]+fcm_fluid[ibody][0]/force->ftm2v)*fflag[ibody][0]*dtfm*dtv;
xcm[ibody][1] += dtv * vcm[ibody][1]+(fcm[ibody][1]+fcm_fluid[ibody][1]/force->ftm2v)*fflag[ibody][1]*dtfm*dtv;
xcm[ibody][2] += dtv * vcm[ibody][2]+(fcm[ibody][2]+fcm_fluid[ibody][2]/force->ftm2v)*fflag[ibody][2]*dtfm*dtv;
rotate[ibody][0] = omega[ibody][0]*dtv + tflag[ibody][0]*(torque[ibody][0]*force->ftm2v+torque_fluid[ibody][0])*
dtv*dtv*5.0/(4.0*masstotal[ibody]*sphereradius[ibody]*sphereradius[ibody]);
rotate[ibody][1] = omega[ibody][1]*dtv + tflag[ibody][1]*(torque[ibody][1]*force->ftm2v+torque_fluid[ibody][1])*
dtv*dtv*5.0/(4.0*masstotal[ibody]*sphereradius[ibody]*sphereradius[ibody]);
rotate[ibody][2] = omega[ibody][2]*dtv + tflag[ibody][2]*(torque[ibody][2]*force->ftm2v+torque_fluid[ibody][2])*
dtv*dtv*5.0/(4.0*masstotal[ibody]*sphereradius[ibody]*sphereradius[ibody]);
// Approximate vcm
expminusdttimesgamma = exp(-Gamma_MD[ibody]*dtv*nrigid_shell[ibody]/masstotal[ibody]);
force_factor = force->ftm2v/Gamma_MD[ibody]/nrigid_shell[ibody];
if(fflag[ibody][0]==1){
vcm[ibody][0] = expminusdttimesgamma*(vcm[ibody][0] - ucm[ibody][0] - fcm[ibody][0]*force_factor)
+ ucm[ibody][0] + fcm[ibody][0]*force_factor;
}
if(fflag[ibody][1]==1){
vcm[ibody][1] = expminusdttimesgamma*(vcm[ibody][1] - ucm[ibody][1] - fcm[ibody][1]*force_factor) +
ucm[ibody][1] + fcm[ibody][1]*force_factor;
}
if(fflag[ibody][2]==1){
vcm[ibody][2] = expminusdttimesgamma*(vcm[ibody][2] - ucm[ibody][2] - fcm[ibody][2]*force_factor) +
ucm[ibody][2] + fcm[ibody][2]*force_factor;
}
// Approximate angmom
torque_factor = 5.0*Gamma_MD[ibody]*nrigid_shell[ibody]/(3.0*masstotal[ibody]);
expminusdttimesgamma = exp(-dtv*torque_factor);
if(tflag[ibody][0]==1){
omega[ibody][0] = expminusdttimesgamma*(omega[ibody][0] - (3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*
(force->ftm2v*torque[ibody][0] + torque_fluid[ibody][0])) +
(3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*
(force->ftm2v*torque[ibody][0] + torque_fluid[ibody][0]);
}
if(tflag[ibody][1]==1){
omega[ibody][1] = expminusdttimesgamma*(omega[ibody][1] - (3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*
(force->ftm2v*torque[ibody][1] + torque_fluid[ibody][1])) +
(3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*
(force->ftm2v*torque[ibody][1] + torque_fluid[ibody][1]);
}
if(tflag[ibody][2]==1){
omega[ibody][2] = expminusdttimesgamma*(omega[ibody][2] - (3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*
(force->ftm2v*torque[ibody][2] + torque_fluid[ibody][2])) +
(3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*
(force->ftm2v*torque[ibody][2] + torque_fluid[ibody][2]);
}
}
// virial setup before call to set_xv
if (vflag) v_setup(vflag);
else evflag = 0;
set_xv();
}
/* ---------------------------------------------------------------------- */
void FixLbRigidPCSphere::final_integrate()
{
int i,ibody;
// sum over atoms to get force and torque on rigid body
double massone;
imageint *image = atom->image;
double **x = atom->x;
double **f = atom->f;
double *rmass = atom->rmass;
double *mass = atom->mass;
int *type = atom->type;
int nlocal = atom->nlocal;
double unwrap[3];
double dx,dy,dz;
int *mask = atom->mask;
for (ibody = 0; ibody < nbody; ibody++)
for (i = 0; i < 6; i++) sum[ibody][i] = 0.0;
for (i = 0; i < nlocal; i++) {
if (body[i] < 0) continue;
ibody = body[i];
sum[ibody][0] += f[i][0];
sum[ibody][1] += f[i][1];
sum[ibody][2] += f[i][2];
domain->unmap(x[i],image[i],unwrap);
dx = unwrap[0] - xcm[ibody][0];
dy = unwrap[1] - xcm[ibody][1];
dz = unwrap[2] - xcm[ibody][2];
sum[ibody][3] += dy*f[i][2] - dz*f[i][1];
sum[ibody][4] += dz*f[i][0] - dx*f[i][2];
sum[ibody][5] += dx*f[i][1] - dy*f[i][0];
}
MPI_Allreduce(sum[0],all[0],6*nbody,MPI_DOUBLE,MPI_SUM,world);
//Compute the correction to the velocity and angular momentum due to the non-fluid forces:
for (ibody = 0; ibody < nbody; ibody++) {
fcm[ibody][0] = all[ibody][0];
fcm[ibody][1] = all[ibody][1];
fcm[ibody][2] = all[ibody][2];
torque[ibody][0] = all[ibody][3];
torque[ibody][1] = all[ibody][4];
torque[ibody][2] = all[ibody][5];
expminusdttimesgamma = exp(-dtv*Gamma_MD[ibody]*nrigid_shell[ibody]/masstotal[ibody]);
DMDcoeff= (dtv - (masstotal[ibody]/nrigid_shell[ibody])*(1.0-expminusdttimesgamma)/Gamma_MD[ibody]);
vcm[ibody][0] += fflag[ibody][0]*DMDcoeff*force->ftm2v*(fcm[ibody][0]-fcm_old[ibody][0])/Gamma_MD[ibody]/dtv/nrigid_shell[ibody];
vcm[ibody][1] += fflag[ibody][1]*DMDcoeff*force->ftm2v*(fcm[ibody][1]-fcm_old[ibody][1])/Gamma_MD[ibody]/dtv/nrigid_shell[ibody];
vcm[ibody][2] += fflag[ibody][2]*DMDcoeff*force->ftm2v*(fcm[ibody][2]-fcm_old[ibody][2])/Gamma_MD[ibody]/dtv/nrigid_shell[ibody];
torque_factor = 5.0*Gamma_MD[ibody]*nrigid_shell[ibody]/(3.0*masstotal[ibody]);
expminusdttimesgamma = exp(-dtv*torque_factor);
DMDcoeff = (dtv - (1.0-expminusdttimesgamma)/torque_factor);
omega[ibody][0] += tflag[ibody][0]*(3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*DMDcoeff*
force->ftm2v*(torque[ibody][0] - torque_old[ibody][0])/dtv;
omega[ibody][1] += tflag[ibody][1]*(3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*DMDcoeff*
force->ftm2v*(torque[ibody][1] - torque_old[ibody][1])/dtv;
omega[ibody][2] += tflag[ibody][2]*(3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*DMDcoeff*
force->ftm2v*(torque[ibody][2] - torque_old[ibody][2])/dtv;
}
//Next, calculate the correction to the velocity and angular momentum due to the fluid forces:
//Calculate the fluid velocity at the new particle locations.
compute_up();
// store fluid quantities for the total body
for (ibody = 0; ibody < nbody; ibody++)
for (i = 0; i < 6; i++) sum[ibody][i] = 0.0;
// Store the fluid velocity at the center of mass, and the total force
// due to the fluid.
for (i = 0; i < nlocal; i++) {
if (body[i] < 0) continue;
ibody = body[i];
if (rmass) massone = rmass[i];
else massone = mass[type[i]];
domain->unmap(x[i],image[i],unwrap);
dx = unwrap[0] - xcm[ibody][0];
dy = unwrap[1] - xcm[ibody][1];
dz = unwrap[2] - xcm[ibody][2];
if(inner_nodes == 1){
if(!(mask[i] & group->bitmask[igroupinner])){
sum[ibody][0] += up[i][0]*massone;
sum[ibody][1] += up[i][1]*massone;
sum[ibody][2] += up[i][2]*massone;
sum[ibody][3] += Gamma_MD[ibody]*(dy * ((up[i][2]-vcm[ibody][2])) -
dz * ((up[i][1]-vcm[ibody][1])));
sum[ibody][4] += Gamma_MD[ibody]*(dz * ((up[i][0]-vcm[ibody][0])) -
dx * ((up[i][2]-vcm[ibody][2])));
sum[ibody][5] += Gamma_MD[ibody]*(dx * ((up[i][1]-vcm[ibody][1])) -
dy * ((up[i][0]-vcm[ibody][0])));
}
}else{
sum[ibody][0] += up[i][0]*massone;
sum[ibody][1] += up[i][1]*massone;
sum[ibody][2] += up[i][2]*massone;
sum[ibody][3] += Gamma_MD[ibody]*(dy * ((up[i][2]-vcm[ibody][2])) -
dz * ((up[i][1]-vcm[ibody][1])));
sum[ibody][4] += Gamma_MD[ibody]*(dz * ((up[i][0]-vcm[ibody][0])) -
dx * ((up[i][2]-vcm[ibody][2])));
sum[ibody][5] += Gamma_MD[ibody]*(dx * ((up[i][1]-vcm[ibody][1])) -
dy * ((up[i][0]-vcm[ibody][0])));
}
}
MPI_Allreduce(sum[0],all[0],6*nbody,MPI_DOUBLE,MPI_SUM,world);
for (ibody = 0; ibody < nbody; ibody++) {
ucm[ibody][0] = all[ibody][0]/masstotal_shell[ibody];
ucm[ibody][1] = all[ibody][1]/masstotal_shell[ibody];
ucm[ibody][2] = all[ibody][2]/masstotal_shell[ibody];
torque_fluid[ibody][0] = all[ibody][3];
torque_fluid[ibody][1] = all[ibody][4];
torque_fluid[ibody][2] = all[ibody][5];
}
for (ibody = 0; ibody < nbody; ibody++) {
expminusdttimesgamma = exp(-dtv*Gamma_MD[ibody]*nrigid_shell[ibody]/masstotal[ibody]);
DMDcoeff= (dtv - (masstotal[ibody]/nrigid_shell[ibody])*(1.0-expminusdttimesgamma)/Gamma_MD[ibody]);
vcm[ibody][0] += DMDcoeff*fflag[ibody][0]*(ucm[ibody][0]-ucm_old[ibody][0])/dtv;
vcm[ibody][1] += DMDcoeff*fflag[ibody][1]*(ucm[ibody][1]-ucm_old[ibody][1])/dtv;
vcm[ibody][2] += DMDcoeff*fflag[ibody][2]*(ucm[ibody][2]-ucm_old[ibody][2])/dtv;
torque_factor = 5.0*Gamma_MD[ibody]*nrigid_shell[ibody]/(3.0*masstotal[ibody]);
expminusdttimesgamma = exp(-dtv*torque_factor);
DMDcoeff = (dtv - (1.0-expminusdttimesgamma)/torque_factor);
omega[ibody][0] += tflag[ibody][0]*(3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*
DMDcoeff*(torque_fluid[ibody][0] - torque_fluid_old[ibody][0])/dtv;
omega[ibody][1] += tflag[ibody][1]*(3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*
DMDcoeff*(torque_fluid[ibody][1] - torque_fluid_old[ibody][1])/dtv;
omega[ibody][2] += tflag[ibody][2]*(3.0/(2.0*nrigid_shell[ibody]*sphereradius[ibody]*sphereradius[ibody]*Gamma_MD[ibody]))*
DMDcoeff*(torque_fluid[ibody][2] - torque_fluid_old[ibody][2])/dtv;
}
set_v();
}
/* ----------------------------------------------------------------------
set space-frame velocity of each atom in a rigid body
set omega and angmom of extended particles
v = Vcm + (W cross (x - Xcm))
------------------------------------------------------------------------- */
void FixLbRigidPCSphere::set_v()
{
int ibody;
int xbox,ybox,zbox;
double dx,dy,dz;
double x0,x1,x2,v0,v1,v2,fc0,fc1,fc2,massone;
double vr[6];
double **x = atom->x;
double **v = atom->v;
double **f = atom->f;
double *rmass = atom->rmass;
double *mass = atom->mass;
int *type = atom->type;
imageint *image = atom->image;
int nlocal = atom->nlocal;
double xprd = domain->xprd;
double yprd = domain->yprd;
double zprd = domain->zprd;
double xunwrap,yunwrap,zunwrap;
// set v of each atom
for (int i = 0; i < nlocal; i++) {
if (body[i] < 0) continue;
ibody = body[i];
xbox = (image[i] & IMGMASK) - IMGMAX;
ybox = (image[i] >> IMGBITS & IMGMASK) - IMGMAX;
zbox = (image[i] >> IMG2BITS) - IMGMAX;
xunwrap = x[i][0] + xbox*xprd;
yunwrap = x[i][1] + ybox*yprd;
zunwrap = x[i][2] + zbox*zprd;
dx = xunwrap - xcm[ibody][0];
dy = yunwrap - xcm[ibody][1];
dz = zunwrap - xcm[ibody][2];
// save old velocities for virial.
if(evflag){
v0 = v[i][0];
v1 = v[i][1];
v2 = v[i][2];
}
v[i][0] = (omega[ibody][1]*dz - omega[ibody][2]*dy) + vcm[ibody][0];
v[i][1] = (omega[ibody][2]*dx - omega[ibody][0]*dz) + vcm[ibody][1];
v[i][2] = (omega[ibody][0]*dy - omega[ibody][1]*dx) + vcm[ibody][2];
// virial = unwrapped coords dotted into body constraint force
// body constraint force = implied force due to v change minus f external
// assume f does not include forces internal to body
// 1/2 factor b/c initial_integrate contributes other half
// assume per-atom contribution is due to constraint force on that atom
if (evflag) {
if (rmass) massone = rmass[i];
else massone = mass[type[i]];
fc0 = massone*(v[i][0] - v0)/dtf - f[i][0] + Gamma_MD[ibody]*(v0-up[i][0]);
fc1 = massone*(v[i][1] - v1)/dtf - f[i][1] + Gamma_MD[ibody]*(v1-up[i][1]);
fc2 = massone*(v[i][2] - v2)/dtf - f[i][2] + Gamma_MD[ibody]*(v2-up[i][2]);
xbox = (image[i] & IMGMASK) - IMGMAX;
ybox = (image[i] >> IMGBITS & IMGMASK) - IMGMAX;
zbox = (image[i] >> IMG2BITS) - IMGMAX;
x0 = x[i][0] + xbox*xprd;
x1 = x[i][1] + ybox*yprd;
x2 = x[i][2] + zbox*zprd;
vr[0] = 0.5*x0*fc0;
vr[1] = 0.5*x1*fc1;
vr[2] = 0.5*x2*fc2;
vr[3] = 0.5*x0*fc1;
vr[4] = 0.5*x0*fc2;
vr[5] = 0.5*x1*fc2;
v_tally(1,&i,1.0,vr);
}
}
}
/* ----------------------------------------------------------------------
set space-frame coords and velocity of each atom in each rigid body
set orientation and rotation of extended particles
x = Q displace + Xcm, mapped back to periodic box
v = Vcm + (W cross (x - Xcm))
------------------------------------------------------------------------- */
void FixLbRigidPCSphere::set_xv()
{
int ibody;
int xbox,ybox,zbox;
double x0,x1,x2,v0,v1,v2,fc0,fc1,fc2,massone;
double vr[6];
double **x = atom->x;
double **v = atom->v;
double **f = atom->f;
double *rmass = atom->rmass;
double *mass = atom->mass;
int *type = atom->type;
imageint *image = atom->image;
int nlocal = atom->nlocal;
double xprd = domain->xprd;
double yprd = domain->yprd;
double zprd = domain->zprd;
double xunwrap,yunwrap,zunwrap;
double dx,dy,dz;
// set x and v of each atom
for (int i = 0; i < nlocal; i++) {
if (body[i] < 0) continue;
ibody = body[i];
xbox = (image[i] & IMGMASK) - IMGMAX;
ybox = (image[i] >> IMGBITS & IMGMASK) - IMGMAX;
zbox = (image[i] >> IMG2BITS) - IMGMAX;
xunwrap = x[i][0] + xbox*xprd;
yunwrap = x[i][1] + ybox*yprd;
zunwrap = x[i][2] + zbox*zprd;
dx = xunwrap - xcm_old[ibody][0];
dy = yunwrap - xcm_old[ibody][1];
dz = zunwrap - xcm_old[ibody][2];
// save old positions and velocities for virial
if(evflag){
x0 = xunwrap;
x1 = yunwrap;
x2 = zunwrap;
v0 = v[i][0];
v1 = v[i][1];
v2 = v[i][2];
}
// x = displacement from center-of-mass, based on body orientation
// v = vcm + omega around center-of-mass
x[i][0] = dx;
x[i][1] = dy;
x[i][2] = dz;
//Perform the rotations:
dx = x[i][0];
dy = x[i][1];
dz = x[i][2];
x[i][0] = cos(rotate[ibody][2])*dx - sin(rotate[ibody][2])*dy;
x[i][1] = sin(rotate[ibody][2])*dx + cos(rotate[ibody][2])*dy;
dx = x[i][0];
dy = x[i][1];
dz = x[i][2];
x[i][0] = cos(rotate[ibody][1])*dx + sin(rotate[ibody][1])*dz;
x[i][2] = -sin(rotate[ibody][1])*dx + cos(rotate[ibody][1])*dz;
dx = x[i][0];
dy = x[i][1];
dz = x[i][2];
x[i][1] = cos(rotate[ibody][0])*dy - sin(rotate[ibody][0])*dz;
x[i][2] = sin(rotate[ibody][0])*dy + cos(rotate[ibody][0])*dz;
v[i][0] = (omega[ibody][1]*x[i][2] - omega[ibody][2]*x[i][1]) + vcm[ibody][0];
v[i][1] = (omega[ibody][2]*x[i][0] - omega[ibody][0]*x[i][2]) + vcm[ibody][1];
v[i][2] = (omega[ibody][0]*x[i][1] - omega[ibody][1]*x[i][0]) + vcm[ibody][2];
// add center of mass to displacement
// map back into periodic box via xbox,ybox,zbox
// for triclinic, add in box tilt factors as well
x[i][0] += xcm[ibody][0] - xbox*xprd;
x[i][1] += xcm[ibody][1] - ybox*yprd;
x[i][2] += xcm[ibody][2] - zbox*zprd;
// virial = unwrapped coords dotted into body constraint force
// body constraint force = implied force due to v change minus f external
// assume f does not include forces internal to body
// 1/2 factor b/c final_integrate contributes other half
// assume per-atom contribution is due to constraint force on that atom
if (evflag) {
if (rmass) massone = rmass[i];
else massone = mass[type[i]];
fc0 = massone*(v[i][0] - v0)/dtf - f[i][0] + Gamma_MD[ibody]*(v0-up[i][0]);
fc1 = massone*(v[i][1] - v1)/dtf - f[i][1] + Gamma_MD[ibody]*(v1-up[i][1]);
fc2 = massone*(v[i][2] - v2)/dtf - f[i][2] + Gamma_MD[ibody]*(v2-up[i][2]);
vr[0] = 0.5*x0*fc0;
vr[1] = 0.5*x1*fc1;
vr[2] = 0.5*x2*fc2;
vr[3] = 0.5*x0*fc1;
vr[4] = 0.5*x0*fc2;
vr[5] = 0.5*x1*fc2;
v_tally(1,&i,1.0,vr);
}
}
}
/* ----------------------------------------------------------------------
remap xcm of each rigid body back into periodic simulation box
done during pre_neighbor so will be after call to pbc()
and after fix_deform::pre_exchange() may have flipped box
use domain->remap() in case xcm is far away from box
due to 1st definition of rigid body or due to box flip
if don't do this, then atoms of a body which drifts far away
from a triclinic box will be remapped back into box
with huge displacements when the box tilt changes via set_x()
------------------------------------------------------------------------- */
void FixLbRigidPCSphere::pre_neighbor()
{
imageint original,oldimage,newimage;
for (int ibody = 0; ibody < nbody; ibody++) {
original = imagebody[ibody];
domain->remap(xcm[ibody],imagebody[ibody]);
if (original == imagebody[ibody]) remapflag[ibody][3] = 0;
else {
oldimage = original & IMGMASK;
newimage = imagebody[ibody] & IMGMASK;
remapflag[ibody][0] = newimage - oldimage;
oldimage = (original >> IMGBITS) & IMGMASK;
newimage = (imagebody[ibody] >> IMGBITS) & IMGMASK;
remapflag[ibody][1] = newimage - oldimage;
oldimage = original >> IMG2BITS;
newimage = imagebody[ibody] >> IMG2BITS;
remapflag[ibody][2] = newimage - oldimage;
remapflag[ibody][3] = 1;
}
}
// adjust image flags of any atom in a rigid body whose xcm was remapped
imageint *atomimage = atom->image;
int nlocal = atom->nlocal;
int ibody;
imageint idim,otherdims;
for (int i = 0; i < nlocal; i++) {
if (body[i] == -1) continue;
if (remapflag[body[i]][3] == 0) continue;
ibody = body[i];
if (remapflag[ibody][0]) {
idim = atomimage[i] & IMGMASK;
otherdims = atomimage[i] ^ idim;
idim -= remapflag[ibody][0];
idim &= IMGMASK;
atomimage[i] = otherdims | idim;
}
if (remapflag[ibody][1]) {
idim = (atomimage[i] >> IMGBITS) & IMGMASK;
otherdims = atomimage[i] ^ (idim << IMGBITS);
idim -= remapflag[ibody][1];
idim &= IMGMASK;
atomimage[i] = otherdims | (idim << IMGBITS);
}
if (remapflag[ibody][2]) {
idim = atomimage[i] >> IMG2BITS;
otherdims = atomimage[i] ^ (idim << IMG2BITS);
idim -= remapflag[ibody][2];
idim &= IMGMASK;
atomimage[i] = otherdims | (idim << IMG2BITS);
}
}
}
/* ----------------------------------------------------------------------
count # of degrees-of-freedom removed by fix_rigid for atoms in igroup
------------------------------------------------------------------------- */
int FixLbRigidPCSphere::dof(int igroup)
{
int groupbit = group->bitmask[igroup];
// ncount = # of atoms in each rigid body that are also in group
int *mask = atom->mask;
int nlocal = atom->nlocal;
int *ncount = new int[nbody];
for (int ibody = 0; ibody < nbody; ibody++) ncount[ibody] = 0;
for (int i = 0; i < nlocal; i++)
if (body[i] >= 0 && mask[i] & groupbit) ncount[body[i]]++;
int *nall = new int[nbody];
MPI_Allreduce(ncount,nall,nbody,MPI_INT,MPI_SUM,world);
// remove 3N - 6 dof for each rigid body if more than 2 atoms in igroup
// remove 3N - 5 dof for each diatomic rigid body in igroup
int n = 0;
for (int ibody = 0; ibody < nbody; ibody++) {
if (nall[ibody] > 2) n += 3*nall[ibody] - 6;
else if (nall[ibody] == 2) n++;
}
delete [] ncount;
delete [] nall;
return n;
}
/* ----------------------------------------------------------------------
memory usage of local atom-based arrays
------------------------------------------------------------------------- */
double FixLbRigidPCSphere::memory_usage()
{
int nmax = atom->nmax;
double bytes = nmax * sizeof(int);
bytes += nmax*3 * sizeof(double);
bytes += maxvatom*6 * sizeof(double);
return bytes;
}
/* ----------------------------------------------------------------------
allocate local atom-based arrays
------------------------------------------------------------------------- */
void FixLbRigidPCSphere::grow_arrays(int nmax)
{
memory->grow(body,nmax,"rigid:body");
memory->grow(up,nmax,3,"rigid:up");
}
/* ----------------------------------------------------------------------
copy values within local atom-based arrays
------------------------------------------------------------------------- */
void FixLbRigidPCSphere::copy_arrays(int i, int j, int delflag)
{
body[j] = body[i];
up[j][0] = up[i][0];
up[j][1] = up[i][1];
up[j][2] = up[i][2];
}
/* ----------------------------------------------------------------------
initialize one atom's array values, called when atom is created
------------------------------------------------------------------------- */
void FixLbRigidPCSphere::set_arrays(int i)
{
body[i] = -1;
up[i][0] = 0.0;
up[i][1] = 0.0;
up[i][2] = 0.0;
}
/* ----------------------------------------------------------------------
pack values in local atom-based arrays for exchange with another proc
------------------------------------------------------------------------- */
int FixLbRigidPCSphere::pack_exchange(int i, double *buf)
{
buf[0] = body[i];
buf[1] = up[i][0];
buf[2] = up[i][1];
buf[3] = up[i][2];
return 4;
}
/* ----------------------------------------------------------------------
unpack values in local atom-based arrays from exchange with another proc
------------------------------------------------------------------------- */
int FixLbRigidPCSphere::unpack_exchange(int nlocal, double *buf)
{
body[nlocal] = static_cast<int> (buf[0]);
up[nlocal][0] = buf[1];
up[nlocal][1] = buf[2];
up[nlocal][2] = buf[3];
return 4;
}
/* ---------------------------------------------------------------------- */
void FixLbRigidPCSphere::reset_dt()
{
dtv = update->dt;
dtf = 0.5 * update->dt * force->ftm2v;
}
/* ----------------------------------------------------------------------
return temperature of collection of rigid bodies
non-active DOF are removed by fflag/tflag and in tfactor
------------------------------------------------------------------------- */
double FixLbRigidPCSphere::compute_scalar()
{
double inertia;
double t = 0.0;
for (int i = 0; i < nbody; i++) {
t += masstotal[i] * (fflag[i][0]*vcm[i][0]*vcm[i][0] +
fflag[i][1]*vcm[i][1]*vcm[i][1] + \
fflag[i][2]*vcm[i][2]*vcm[i][2]);
// wbody = angular velocity in body frame
inertia = 2.0*masstotal[i]*sphereradius[i]*sphereradius[i]/5.0;
t += tflag[i][0]*inertia*omega[i][0]*omega[i][0] +
tflag[i][1]*inertia*omega[i][1]*omega[i][1] +
tflag[i][2]*inertia*omega[i][2]*omega[i][2];
}
t *= tfactor;
return t;
}
/* ----------------------------------------------------------------------
return attributes of a rigid body
15 values per body
xcm = 0,1,2; vcm = 3,4,5; fcm = 6,7,8; torque = 9,10,11; image = 12,13,14
------------------------------------------------------------------------- */
double FixLbRigidPCSphere::compute_array(int i, int j)
{
if (j < 3) return xcm[i][j];
if (j < 6) return vcm[i][j-3];
if (j < 9) return (fcm[i][j-6]+fcm_fluid[i][j-6]);
if (j < 12) return (torque[i][j-9]+torque_fluid[i][j-9]);
if (j == 12) return (imagebody[i] & IMGMASK) - IMGMAX;
if (j == 13) return (imagebody[i] >> IMGBITS & IMGMASK) - IMGMAX;
return (imagebody[i] >> IMG2BITS) - IMGMAX;
}
/* ---------------------------------------------------------------------- */
void FixLbRigidPCSphere::compute_up(void)
{
int *mask = atom->mask;
int nlocal = atom->nlocal;
double **x = atom->x;
int i,k;
int ix,iy,iz;
int ixp,iyp,izp;
double dx1,dy1,dz1;
int isten,ii,jj,kk;
double r,rsq,weightx,weighty,weightz;
double ****u_lb = fix_lb_fluid->u_lb;
int subNbx = fix_lb_fluid->subNbx;
int subNby = fix_lb_fluid->subNby;
int subNbz = fix_lb_fluid->subNbz;
double dx_lb = fix_lb_fluid->dx_lb;
double dt_lb = fix_lb_fluid->dt_lb;
int trilinear_stencil = fix_lb_fluid->trilinear_stencil;
double FfP[64];
for(i=0; i<nlocal; i++){
if(mask[i] & groupbit){
//Calculate nearest leftmost grid point.
//Since array indices from 1 to subNb-2 correspond to the
// local subprocessor domain (not indices from 0), use the
// ceiling value.
ix = (int)ceil((x[i][0]-domain->sublo[0])/dx_lb);
iy = (int)ceil((x[i][1]-domain->sublo[1])/dx_lb);
iz = (int)ceil((x[i][2]-domain->sublo[2])/dx_lb);
//Calculate distances to the nearest points.
dx1 = x[i][0] - (domain->sublo[0] + (ix-1)*dx_lb);
dy1 = x[i][1] - (domain->sublo[1] + (iy-1)*dx_lb);
dz1 = x[i][2] - (domain->sublo[2] + (iz-1)*dx_lb);
// Need to convert these to lattice units:
dx1 = dx1/dx_lb;
dy1 = dy1/dx_lb;
dz1 = dz1/dx_lb;
up[i][0]=0.0; up[i][1]=0.0; up[i][2]=0.0;
if(trilinear_stencil==0){
isten=0;
for(ii=-1; ii<3; ii++){
rsq=(-dx1+ii)*(-dx1+ii);
if(rsq>=4)
weightx=0.0;
else{
r=sqrt(rsq);
if(rsq>1){
weightx=(5.0-2.0*r-sqrt(-7.0+12.0*r-4.0*rsq))/8.;
} else{
weightx=(3.0-2.0*r+sqrt(1.0+4.0*r-4.0*rsq))/8.;
}
}
for(jj=-1; jj<3; jj++){
rsq=(-dy1+jj)*(-dy1+jj);
if(rsq>=4)
weighty=0.0;
else{
r=sqrt(rsq);
if(rsq>1){
weighty=(5.0-2.0*r-sqrt(-7.0+12.0*r-4.0*rsq))/8.;
} else{
weighty=(3.0-2.0*r+sqrt(1.0+4.0*r-4.0*rsq))/8.;
}
}
for(kk=-1; kk<3; kk++){
rsq=(-dz1+kk)*(-dz1+kk);
if(rsq>=4)
weightz=0.0;
else{
r=sqrt(rsq);
if(rsq>1){
weightz=(5.0-2.0*r-sqrt(-7.0+12.0*r-4.0*rsq))/8.;
} else{
weightz=(3.0-2.0*r+sqrt(1.0+4.0*r-4.0*rsq))/8.;
}
}
ixp = ix+ii;
iyp = iy+jj;
izp = iz+kk;
if(ixp==-1) ixp=subNbx+2;
if(iyp==-1) iyp=subNby+2;
if(izp==-1) izp=subNbz+2;
FfP[isten] = weightx*weighty*weightz;
// interpolated velocity based on delta function.
for(k=0; k<3; k++){
up[i][k] += u_lb[ixp][iyp][izp][k]*FfP[isten];
}
}
}
}
}else{
FfP[0] = (1.-dx1)*(1.-dy1)*(1.-dz1);
FfP[1] = (1.-dx1)*(1.-dy1)*dz1;
FfP[2] = (1.-dx1)*dy1*(1.-dz1);
FfP[3] = (1.-dx1)*dy1*dz1;
FfP[4] = dx1*(1.-dy1)*(1.-dz1);
FfP[5] = dx1*(1.-dy1)*dz1;
FfP[6] = dx1*dy1*(1.-dz1);
FfP[7] = dx1*dy1*dz1;
ixp = (ix+1);
iyp = (iy+1);
izp = (iz+1);
for (k=0; k<3; k++) { // tri-linearly interpolated velocity at node
up[i][k] = u_lb[ix][iy][iz][k]*FfP[0]
+ u_lb[ix][iy][izp][k]*FfP[1]
+ u_lb[ix][iyp][iz][k]*FfP[2]
+ u_lb[ix][iyp][izp][k]*FfP[3]
+ u_lb[ixp][iy][iz][k]*FfP[4]
+ u_lb[ixp][iy][izp][k]*FfP[5]
+ u_lb[ixp][iyp][iz][k]*FfP[6]
+ u_lb[ixp][iyp][izp][k]*FfP[7];
}
}
for(k=0; k<3; k++)
up[i][k] = up[i][k]*dx_lb/dt_lb;
}
}
}

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