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pair_sph_heatconduction.cpp
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Sat, Nov 2, 01:18

pair_sph_heatconduction.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.
------------------------------------------------------------------------- */
#include "math.h"
#include "stdlib.h"
#include "pair_sph_heatconduction.h"
#include "atom.h"
#include "force.h"
#include "comm.h"
#include "memory.h"
#include "error.h"
#include "neigh_list.h"
#include "domain.h"
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
PairSPHHeatConduction::PairSPHHeatConduction(LAMMPS *lmp) : Pair(lmp)
{
restartinfo = 0;
}
/* ---------------------------------------------------------------------- */
PairSPHHeatConduction::~PairSPHHeatConduction() {
if (allocated) {
memory->destroy(setflag);
memory->destroy(cutsq);
memory->destroy(cut);
memory->destroy(alpha);
}
}
/* ---------------------------------------------------------------------- */
void PairSPHHeatConduction::compute(int eflag, int vflag) {
int i, j, ii, jj, inum, jnum, itype, jtype;
double xtmp, ytmp, ztmp, delx, dely, delz;
int *ilist, *jlist, *numneigh, **firstneigh;
double imass, jmass, h, ih, ihsq;
double rsq, wfd, D, deltaE;
if (eflag || vflag)
ev_setup(eflag, vflag);
else
evflag = vflag_fdotr = 0;
double **x = atom->x;
double *e = atom->e;
double *de = atom->de;
double *mass = atom->mass;
double *rho = atom->rho;
int *type = atom->type;
int nlocal = atom->nlocal;
int newton_pair = force->newton_pair;
inum = list->inum;
ilist = list->ilist;
numneigh = list->numneigh;
firstneigh = list->firstneigh;
// loop over neighbors of my atoms and do heat diffusion
for (ii = 0; ii < inum; ii++) {
i = ilist[ii];
itype = type[i];
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
jlist = firstneigh[i];
jnum = numneigh[i];
imass = mass[itype];
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;
jtype = type[j];
jmass = mass[jtype];
if (rsq < cutsq[itype][jtype]) {
h = cut[itype][jtype];
ih = 1.0 / h;
ihsq = ih * ih;
// kernel function
wfd = h - sqrt(rsq);
if (domain->dimension == 3) {
// Lucy Kernel, 3d
// Note that wfd, the derivative of the weight function with respect to r,
// is lacking a factor of r.
// The missing factor of r is recovered by
// deltaE, which is missing a factor of 1/r
wfd = -25.066903536973515383e0 * wfd * wfd * ihsq * ihsq * ihsq * ih;
} else {
// Lucy Kernel, 2d
wfd = -19.098593171027440292e0 * wfd * wfd * ihsq * ihsq * ihsq;
}
jmass = mass[jtype];
D = alpha[itype][jtype]; // diffusion coefficient
deltaE = 2.0 * imass * jmass / (imass+jmass);
deltaE *= (rho[i] + rho[j]) / (rho[i] * rho[j]);
deltaE *= D * (e[i] - e[j]) * wfd;
de[i] += deltaE;
if (newton_pair || j < nlocal) {
de[j] -= deltaE;
}
}
}
}
}
/* ----------------------------------------------------------------------
allocate all arrays
------------------------------------------------------------------------- */
void PairSPHHeatConduction::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(cut, n + 1, n + 1, "pair:cut");
memory->create(alpha, n + 1, n + 1, "pair:alpha");
}
/* ----------------------------------------------------------------------
global settings
------------------------------------------------------------------------- */
void PairSPHHeatConduction::settings(int narg, char **arg) {
if (narg != 0)
error->all(FLERR,
"Illegal number of setting arguments for pair_style sph/heatconduction");
}
/* ----------------------------------------------------------------------
set coeffs for one or more type pairs
------------------------------------------------------------------------- */
void PairSPHHeatConduction::coeff(int narg, char **arg) {
if (narg != 4)
error->all(FLERR,"Incorrect number of args for pair_style sph/heatconduction 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 alpha_one = force->numeric(arg[2]);
double cut_one = force->numeric(arg[3]);
int count = 0;
for (int i = ilo; i <= ihi; i++) {
for (int j = MAX(jlo,i); j <= jhi; j++) {
//printf("setting cut[%d][%d] = %f\n", i, j, cut_one);
cut[i][j] = cut_one;
alpha[i][j] = alpha_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 PairSPHHeatConduction::init_one(int i, int j) {
if (setflag[i][j] == 0) {
error->all(FLERR,"All pair sph/heatconduction coeffs are not set");
}
cut[j][i] = cut[i][j];
alpha[j][i] = alpha[i][j];
return cut[i][j];
}
/* ---------------------------------------------------------------------- */
double PairSPHHeatConduction::single(int i, int j, int itype, int jtype,
double rsq, double factor_coul, double factor_lj, double &fforce) {
fforce = 0.0;
return 0.0;
}

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