Page Menu
Home
c4science
Search
Configure Global Search
Log In
Files
F74420092
pair_peri_ves.cpp
No One
Temporary
Actions
Download File
Edit File
Delete File
View Transforms
Subscribe
Mute Notifications
Award Token
Subscribers
None
File Metadata
Details
File Info
Storage
Attached
Created
Sat, Jul 27, 18:12
Size
21 KB
Mime Type
text/x-c
Expires
Mon, Jul 29, 18:12 (2 d)
Engine
blob
Format
Raw Data
Handle
19362781
Attached To
rLAMMPS lammps
pair_peri_ves.cpp
View Options
/* ----------------------------------------------------------------------
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: Ezwanur Rahman, J.T. Foster (UTSA)
------------------------------------------------------------------------- */
#include "math.h"
#include "stdlib.h"
#include "string.h"
#include "pair_peri_ves.h"
#include "atom.h"
#include "domain.h"
#include "lattice.h"
#include "force.h"
#include "update.h"
#include "modify.h"
#include "fix.h"
#include "fix_peri_neigh.h"
#include "comm.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "memory.h"
#include "error.h"
#include "update.h"
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
PairPeriVES::PairPeriVES(LAMMPS *lmp) : Pair(lmp)
{
for (int i = 0; i < 6; i++) virial[i] = 0.0;
no_virial_fdotr_compute = 1;
single_enable = 0;
ifix_peri = -1;
nmax = 0;
s0_new = NULL;
theta = NULL;
bulkmodulus = NULL;
shearmodulus = NULL;
s00 = alpha = NULL;
cut = NULL;
m_lambdai = NULL;
m_taubi = NULL;
// set comm size needed by this Pair
// comm_reverse not needed
comm_forward = 1;
}
/* ---------------------------------------------------------------------- */
PairPeriVES::~PairPeriVES()
{
if (ifix_peri >= 0) modify->delete_fix("PERI_NEIGH");
if (allocated) {
memory->destroy(setflag);
memory->destroy(cutsq);
memory->destroy(bulkmodulus);
memory->destroy(shearmodulus);
memory->destroy(s00);
memory->destroy(alpha);
memory->destroy(cut);
memory->destroy(m_lambdai);
memory->destroy(m_taubi);
memory->destroy(theta);
memory->destroy(s0_new);
}
}
/* ---------------------------------------------------------------------- */
void PairPeriVES::compute(int eflag, int vflag)
{
int i,j,ii,jj,inum,jnum,itype,jtype;
double xtmp,ytmp,ztmp,delx,dely,delz;
double xtmp0,ytmp0,ztmp0,delx0,dely0,delz0,rsq0;
double rsq,r,dr,rk,evdwl,fpair,fbond;
double deltaed,fbondViscoElastic,fbondFinal;
double decay,betai,lambdai,edbNp1,rkNew;
int *ilist,*jlist,*numneigh,**firstneigh;
double d_ij,delta,stretch;
evdwl = 0.0;
if (eflag || vflag) ev_setup(eflag,vflag);
else evflag = vflag_fdotr = eflag_global = eflag_atom = 0;
double **f = atom->f;
double **x = atom->x;
int *type = atom->type;
int nlocal = atom->nlocal;
double timestepsize = update->dt;
double *vfrac = atom->vfrac;
double *s0 = atom->s0;
double **x0 = atom->x0;
double **r0 = ((FixPeriNeigh *) modify->fix[ifix_peri])->r0;
double **deviatorextention =
((FixPeriNeigh *) modify->fix[ifix_peri])->deviatorextention;
double **deviatorBackextention =
((FixPeriNeigh *) modify->fix[ifix_peri])->deviatorBackextention;
tagint **partner = ((FixPeriNeigh *) modify->fix[ifix_peri])->partner;
int *npartner = ((FixPeriNeigh *) modify->fix[ifix_peri])->npartner;
double *wvolume = ((FixPeriNeigh *) modify->fix[ifix_peri])->wvolume;
// lc = lattice constant
// init_style guarantees it's the same in x, y, and z
double lc = domain->lattice->xlattice;
double half_lc = 0.5*lc;
double vfrac_scale = 1.0;
// short-range forces
int newton_pair = force->newton_pair;
int periodic = domain->xperiodic || domain->yperiodic || domain->zperiodic;
inum = list->inum;
ilist = list->ilist;
numneigh = list->numneigh;
firstneigh = list->firstneigh;
// loop over neighbors of my atoms
// need minimg() for x0 difference since not ghosted
for (ii = 0; ii < inum; ii++) {
i = ilist[ii];
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
xtmp0 = x0[i][0];
ytmp0 = x0[i][1];
ztmp0 = x0[i][2];
itype = type[i];
jlist = firstneigh[i];
jnum = numneigh[i];
for (jj = 0; jj < jnum; jj++) {
j = jlist[jj];
j &= NEIGHMASK;
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
rsq = delx*delx + dely*dely + delz*delz;
delx0 = xtmp0 - x0[j][0];
dely0 = ytmp0 - x0[j][1];
delz0 = ztmp0 - x0[j][2];
if (periodic) domain->minimum_image(delx0,dely0,delz0);
rsq0 = delx0*delx0 + dely0*dely0 + delz0*delz0;
jtype = type[j];
r = sqrt(rsq);
// short-range interaction distance based on initial particle position
// 0.9 and 1.35 are constants
d_ij = MIN(0.9*sqrt(rsq0),1.35*lc);
// short-range contact forces
// 15 is constant taken from the EMU Theory Manual
// Silling, 12 May 2005, p 18
if (r < d_ij) {
dr = r - d_ij;
// kshort based upon short-range force constant
// of the bond-based theory used in PMB model
double kshort = (15.0 * 18.0 * bulkmodulus[itype][itype]) /
(3.141592653589793 * cutsq[itype][jtype] * cutsq[itype][jtype]);
rk = (kshort * vfrac[j]) * (dr / cut[itype][jtype]);
if (r > 0.0) fpair = -(rk/r);
else fpair = 0.0;
f[i][0] += delx*fpair;
f[i][1] += dely*fpair;
f[i][2] += delz*fpair;
if (newton_pair || j < nlocal) {
f[j][0] -= delx*fpair;
f[j][1] -= dely*fpair;
f[j][2] -= delz*fpair;
}
if (eflag) evdwl = 0.5*rk*dr;
if (evflag) ev_tally(i,j,nlocal,newton_pair,evdwl,0.0,
fpair*vfrac[i],delx,dely,delz);
}
}
}
// grow bond forces array if necessary
if (atom->nmax > nmax) {
memory->destroy(s0_new);
memory->destroy(theta);
nmax = atom->nmax;
memory->create(s0_new,nmax,"pair:s0_new");
memory->create(theta,nmax,"pair:theta");
}
// Compute the dilatation on each particle
compute_dilatation();
// communicate dilatation (theta) of each particle
comm->forward_comm_pair(this);
// communicate weighted volume (wvolume) upon every reneighbor
if (neighbor->ago == 0)
comm->forward_comm_fix(modify->fix[ifix_peri]);
// volume-dependent part of the energy
if (eflag) {
for (i = 0; i < nlocal; i++) {
itype = type[i];
if (eflag_global)
eng_vdwl += 0.5 * bulkmodulus[itype][itype] * (theta[i] * theta[i]);
if (eflag_atom)
eatom[i] += 0.5 * bulkmodulus[itype][itype] * (theta[i] * theta[i]);
}
}
// loop over my particles and their partners
// partner list contains all bond partners, so I-J appears twice
// if bond already broken, skip this partner
// first = true if this is first neighbor of particle i
bool first;
double omega_minus, omega_plus;
for (i = 0; i < nlocal; i++) {
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
xtmp0 = x0[i][0];
ytmp0 = x0[i][1];
ztmp0 = x0[i][2];
itype = type[i];
jnum = npartner[i];
first = true;
for (jj = 0; jj < jnum; jj++) {
if (partner[i][jj] == 0) continue;
j = atom->map(partner[i][jj]);
// check if lost a partner without first breaking bond
if (j < 0) {
partner[i][jj] = 0;
continue;
}
// compute force density, add to PD equation of motion
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
if (periodic) domain->minimum_image(delx,dely,delz);
rsq = delx*delx + dely*dely + delz*delz;
delx0 = xtmp0 - x0[j][0];
dely0 = ytmp0 - x0[j][1];
delz0 = ztmp0 - x0[j][2];
if (periodic) domain->minimum_image(delx0,dely0,delz0);
jtype = type[j];
delta = cut[itype][jtype];
r = sqrt(rsq);
dr = r - r0[i][jj];
// avoid roundoff errors
if (fabs(dr) < 2.2204e-016) dr = 0.0;
// scale vfrac[j] if particle j near the horizon
if ((fabs(r0[i][jj] - delta)) <= half_lc)
vfrac_scale = (-1.0/(2*half_lc))*(r0[i][jj]) +
(1.0 + ((delta - half_lc)/(2*half_lc) ) );
else vfrac_scale = 1.0;
omega_plus = influence_function(-1.0*delx0,-1.0*dely0,-1.0*delz0);
omega_minus = influence_function(delx0,dely0,delz0);
rk = ( (3.0 * bulkmodulus[itype][itype]) * vfrac[j] * vfrac_scale *
( (omega_plus * theta[i] / wvolume[i]) +
( omega_minus * theta[j] / wvolume[j] ) ) ) * r0[i][jj];
if (r > 0.0) fbond = -(rk/r);
else fbond = 0.0;
// for viscoelasticity
lambdai=m_lambdai[itype][itype];
double taui = m_taubi[itype][itype];
double c1 = taui/timestepsize;
decay=exp(-1.0/c1);
betai=1.-c1*(1.-decay);
double deviatoric_extension =
dr - (theta[i]* r0[i][jj] / 3.0);
deltaed = deviatoric_extension-deviatorextention[i][jj];
// back extention at current step
edbNp1 = deviatorextention[i][jj]*(1-decay) +
deviatorBackextention[i][jj]*decay+betai*deltaed;
rkNew = ((1-lambdai)*15.0) *
( shearmodulus[itype][itype] * vfrac[j] * vfrac_scale ) *
( (omega_plus / wvolume[i]) + (omega_minus / wvolume[j]) ) *
deviatoric_extension;
rkNew += (lambdai*15.0) *
( shearmodulus[itype][itype] * vfrac[j] * vfrac_scale ) *
( (omega_plus / wvolume[i]) + (omega_minus / wvolume[j]) ) *
(deviatoric_extension-edbNp1);
if (r > 0.0) fbondViscoElastic = -(rkNew/r);
else fbondViscoElastic = 0.0;
// total Force: elastic + viscoelastic
fbondFinal=fbond+fbondViscoElastic;
fbond=fbondFinal;
f[i][0] += delx*fbond;
f[i][1] += dely*fbond;
f[i][2] += delz*fbond;
// since I-J is double counted, set newton off & use 1/2 factor and I,I
if (eflag) evdwl = ((0.5 * 15 * (1 - lambdai) * shearmodulus[itype][itype]/wvolume[i] *
omega_plus * deviatoric_extension *
deviatoric_extension) +
(0.5 * 15 * lambdai * shearmodulus[itype][itype]/wvolume[i] *
omega_plus * (deviatoric_extension-edbNp1) *
(deviatoric_extension-edbNp1))) * vfrac[j] * vfrac_scale;
if (evflag) ev_tally(i,i,nlocal,0,0.5*evdwl,0.0,
0.5*fbond*vfrac[i],delx,dely,delz);
// find stretch in bond I-J and break if necessary
// use s0 from previous timestep
// store current deviatoric extention
deviatorextention[i][jj]=deviatoric_extension;
deviatorBackextention[i][jj]=edbNp1;
stretch = dr / r0[i][jj];
if (stretch > MIN(s0[i],s0[j])) partner[i][jj] = 0;
// update s0 for next timestep
if (first)
s0_new[i] = s00[itype][jtype] - (alpha[itype][jtype] * stretch);
else
s0_new[i] = MAX(s0_new[i],s00[itype][jtype] -
(alpha[itype][jtype] * stretch));
first = false;
}
}
// store new s0
for (i = 0; i < nlocal; i++) s0[i] = s0_new[i];
}
/* ----------------------------------------------------------------------
allocate all arrays
------------------------------------------------------------------------- */
void PairPeriVES::allocate()
{
allocated = 1;
int n = atom->ntypes;
memory->create(setflag,n+1,n+1,"pair:setflag");
for (int i = 1; i <= n; i++)
for (int j = i; j <= n; j++)
setflag[i][j] = 0;
memory->create(cutsq,n+1,n+1,"pair:cutsq");
memory->create(bulkmodulus,n+1,n+1,"pair:bulkmodulus");
memory->create(shearmodulus,n+1,n+1,"pair:shearmodulus");
memory->create(s00,n+1,n+1,"pair:s00");
memory->create(alpha,n+1,n+1,"pair:alpha");
memory->create(cut,n+1,n+1,"pair:cut");
memory->create(m_lambdai,n+1,n+1,"pair:m_lambdai");
memory->create(m_taubi,n+1,n+1,"pair:m_taubi");
}
/* ----------------------------------------------------------------------
global settings
------------------------------------------------------------------------- */
void PairPeriVES::settings(int narg, char **arg)
{
if (narg) error->all(FLERR,"Illegal pair_style command");
}
/* ----------------------------------------------------------------------
set coeffs for one or more type pairs
------------------------------------------------------------------------- */
void PairPeriVES::coeff(int narg, char **arg)
{
if (narg != 9) error->all(FLERR,"Incorrect args for pair coefficients");
if (!allocated) allocate();
int ilo,ihi,jlo,jhi;
force->bounds(arg[0],atom->ntypes,ilo,ihi);
force->bounds(arg[1],atom->ntypes,jlo,jhi);
double bulkmodulus_one = atof(arg[2]);
double shearmodulus_one = atof(arg[3]);
double cut_one = atof(arg[4]);
double s00_one = atof(arg[5]);
double alpha_one = atof(arg[6]);
double mlambdai_one = atof(arg[7]);
double mtaui_one = atof(arg[8]);
int count = 0;
for (int i = ilo; i <= ihi; i++) {
for (int j = MAX(jlo,i); j <= jhi; j++) {
bulkmodulus[i][j] = bulkmodulus_one;
shearmodulus[i][j] = shearmodulus_one;
cut[i][j] = cut_one;
s00[i][j] = s00_one;
alpha[i][j] = alpha_one;
m_lambdai[i][j] = mlambdai_one;
m_taubi[i][j] = mtaui_one;
setflag[i][j] = 1;
count++;
}
}
if (count == 0) error->all(FLERR,"Incorrect args for pair coefficients");
}
/* ----------------------------------------------------------------------
init for one type pair i,j and corresponding j,i
------------------------------------------------------------------------- */
double PairPeriVES::init_one(int i, int j)
{
if (setflag[i][j] == 0) error->all(FLERR,"All pair coeffs are not set");
bulkmodulus[j][i] = bulkmodulus[i][j];
shearmodulus[j][i] = shearmodulus[i][j];
s00[j][i] = s00[i][j];
alpha[j][i] = alpha[i][j];
cut[j][i] = cut[i][j];
m_lambdai[j][i] = m_lambdai[i][j];
m_taubi[j][i] = m_taubi[i][j];
return cut[i][j];
}
/* ----------------------------------------------------------------------
init specific to this pair style
------------------------------------------------------------------------- */
void PairPeriVES::init_style()
{
// error checks
if (!atom->peri_flag)
error->all(FLERR,"Pair style peri requires atom style peri");
if (atom->map_style == 0)
error->all(FLERR,"Pair peri requires an atom map, see atom_modify");
if (domain->lattice == NULL)
error->all(FLERR,"Pair peri requires a lattice be defined");
if (domain->lattice->xlattice != domain->lattice->ylattice ||
domain->lattice->xlattice != domain->lattice->zlattice ||
domain->lattice->ylattice != domain->lattice->zlattice)
error->all(FLERR,"Pair peri lattice is not identical in x, y, and z");
// if first init, create Fix needed for storing fixed neighbors
if (ifix_peri == -1) {
char **fixarg = new char*[3];
fixarg[0] = (char *) "PERI_NEIGH";
fixarg[1] = (char *) "all";
fixarg[2] = (char *) "PERI_NEIGH";
modify->add_fix(3,fixarg);
delete [] fixarg;
}
// find associated PERI_NEIGH fix that must exist
// could have changed locations in fix list since created
for (int i = 0; i < modify->nfix; i++)
if (strcmp(modify->fix[i]->style,"PERI_NEIGH") == 0) ifix_peri = i;
if (ifix_peri == -1) error->all(FLERR,"Fix peri neigh does not exist");
neighbor->request(this);
}
/* ----------------------------------------------------------------------
proc 0 writes to restart file
------------------------------------------------------------------------- */
void PairPeriVES::write_restart(FILE *fp)
{
int i,j;
for (i = 1; i <= atom->ntypes; i++)
for (j = i; j <= atom->ntypes; j++) {
fwrite(&setflag[i][j],sizeof(int),1,fp);
if (setflag[i][j]) {
fwrite(&bulkmodulus[i][j],sizeof(double),1,fp);
fwrite(&shearmodulus[i][j],sizeof(double),1,fp);
fwrite(&s00[i][j],sizeof(double),1,fp);
fwrite(&alpha[i][j],sizeof(double),1,fp);
fwrite(&cut[i][j],sizeof(double),1,fp);
fwrite(&m_lambdai[i][j],sizeof(double),1,fp);
fwrite(&m_taubi[i][j],sizeof(double),1,fp);
}
}
}
/* ----------------------------------------------------------------------
proc 0 reads from restart file, bcasts
------------------------------------------------------------------------- */
void PairPeriVES::read_restart(FILE *fp)
{
allocate();
int i,j;
int me = comm->me;
for (i = 1; i <= atom->ntypes; i++)
for (j = i; j <= atom->ntypes; j++) {
if (me == 0) fread(&setflag[i][j],sizeof(int),1,fp);
MPI_Bcast(&setflag[i][j],1,MPI_INT,0,world);
if (setflag[i][j]) {
if (me == 0) {
fread(&bulkmodulus[i][j],sizeof(double),1,fp);
fread(&shearmodulus[i][j],sizeof(double),1,fp);
fread(&s00[i][j],sizeof(double),1,fp);
fread(&alpha[i][j],sizeof(double),1,fp);
fread(&cut[i][j],sizeof(double),1,fp);
fread(&m_lambdai[i][j],sizeof(double),1,fp);
fread(&m_taubi[i][j],sizeof(double),1,fp);
}
MPI_Bcast(&bulkmodulus[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&shearmodulus[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&s00[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&alpha[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&cut[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&m_lambdai[i][j],1,MPI_DOUBLE,0,world);
MPI_Bcast(&m_taubi[i][j],1,MPI_DOUBLE,0,world);
}
}
}
/* ----------------------------------------------------------------------
memory usage of local atom-based arrays
------------------------------------------------------------------------- */
double PairPeriVES::memory_usage()
{
double bytes = 2 * nmax * sizeof(double);
return bytes;
}
/* ----------------------------------------------------------------------
influence function definition
------------------------------------------------------------------------- */
double PairPeriVES::influence_function(double xi_x, double xi_y, double xi_z)
{
double r = sqrt(xi_x*xi_x + xi_y*xi_y + xi_z*xi_z);
double omega;
if (fabs(r) < 2.2204e-016)
error->one(FLERR,"Divide by 0 in influence function of pair peri/lps");
omega = 1.0/r;
return omega;
}
/* ---------------------------------------------------------------------- */
void PairPeriVES::compute_dilatation()
{
int i,j,jj,jnum,itype,jtype;
double xtmp,ytmp,ztmp,delx,dely,delz;
double xtmp0,ytmp0,ztmp0,delx0,dely0,delz0;
double rsq,r,dr;
double delta;
double **x = atom->x;
int *type = atom->type;
double **x0 = atom->x0;
int nlocal = atom->nlocal;
double *vfrac = atom->vfrac;
double vfrac_scale = 1.0;
double lc = domain->lattice->xlattice;
double half_lc = 0.5*lc;
double **r0 = ((FixPeriNeigh *) modify->fix[ifix_peri])->r0;
tagint **partner = ((FixPeriNeigh *) modify->fix[ifix_peri])->partner;
int *npartner = ((FixPeriNeigh *) modify->fix[ifix_peri])->npartner;
double *wvolume = ((FixPeriNeigh *) modify->fix[ifix_peri])->wvolume;
int periodic = domain->xperiodic || domain->yperiodic || domain->zperiodic;
// compute the dilatation theta
for (i = 0; i < nlocal; i++) {
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
xtmp0 = x0[i][0];
ytmp0 = x0[i][1];
ztmp0 = x0[i][2];
jnum = npartner[i];
theta[i] = 0.0;
itype = type[i];
for (jj = 0; jj < jnum; jj++) {
// if bond already broken, skip this partner
if (partner[i][jj] == 0) continue;
// look up local index of this partner particle
j = atom->map(partner[i][jj]);
// skip if particle is "lost"
if (j < 0) continue;
// compute force density and add to PD equation of motion
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
if (periodic) domain->minimum_image(delx,dely,delz);
rsq = delx*delx + dely*dely + delz*delz;
delx0 = xtmp0 - x0[j][0];
dely0 = ytmp0 - x0[j][1];
delz0 = ztmp0 - x0[j][2];
if (periodic) domain->minimum_image(delx0,dely0,delz0);
r = sqrt(rsq);
dr = r - r0[i][jj];
if (fabs(dr) < 2.2204e-016) dr = 0.0;
jtype = type[j];
delta = cut[itype][jtype];
// scale vfrac[j] if particle j near the horizon
if ((fabs(r0[i][jj] - delta)) <= half_lc)
vfrac_scale = (-1.0/(2*half_lc))*(r0[i][jj]) +
(1.0 + ((delta - half_lc)/(2*half_lc) ) );
else vfrac_scale = 1.0;
theta[i] += influence_function(delx0, dely0, delz0) * r0[i][jj] * dr *
vfrac[j] * vfrac_scale;
}
// if wvolume[i] is zero, then particle i has no bonds
// therefore, the dilatation is set to
if (wvolume[i] != 0.0) theta[i] = (3.0/wvolume[i]) * theta[i];
else theta[i] = 0;
}
}
/* ----------------------------------------------------------------------
communication routines
---------------------------------------------------------------------- */
int PairPeriVES::pack_forward_comm(int n, int *list, double *buf,
int pbc_flag, int *pbc)
{
int i,j,m;
m = 0;
for (i = 0; i < n; i++) {
j = list[i];
buf[m++] = theta[j];
}
return m;
}
/* ---------------------------------------------------------------------- */
void PairPeriVES::unpack_forward_comm(int n, int first, double *buf)
{
int i,m,last;
m = 0;
last = first + n;
for (i = first; i < last; i++) {
theta[i] = buf[m++];
}
}
Event Timeline
Log In to Comment