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pair_coul_streitz.cpp
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Thu, Nov 7, 23:30

pair_coul_streitz.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: Ray Shan (Sandia)
------------------------------------------------------------------------- */
#include "math.h"
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "pair_coul_streitz.h"
#include "atom.h"
#include "comm.h"
#include "force.h"
#include "kspace.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "neigh_request.h"
#include "group.h"
#include "update.h"
#include "math_const.h"
#include "memory.h"
#include "error.h"
using namespace LAMMPS_NS;
using namespace MathConst;
#define MAXLINE 1024
#define DELTA 4
#define PGDELTA 1
#define MAXNEIGH 24
/* ---------------------------------------------------------------------- */
PairCoulStreitz::PairCoulStreitz(LAMMPS *lmp) : Pair(lmp)
{
single_enable = 0;
restartinfo = 0;
one_coeff = 1;
nmax = 0;
nelements = 0;
elements = NULL;
nparams = 0;
maxparam = 0;
params = NULL;
elem2param = NULL;
}
/* ----------------------------------------------------------------------
check if allocated, since class can be destructed when incomplete
------------------------------------------------------------------------- */
PairCoulStreitz::~PairCoulStreitz()
{
if (elements)
for (int i = 0; i < nelements; i++) delete [] elements[i];
delete [] elements;
memory->sfree(params);
memory->destroy(elem2param);
if (allocated) {
memory->destroy(setflag);
memory->destroy(cutsq);
memory->destroy(scale);
memory->destroy(qeq_x);
memory->destroy(qeq_j);
memory->destroy(qeq_g);
memory->destroy(qeq_z);
memory->destroy(qeq_c);
delete [] map;
}
}
/* ---------------------------------------------------------------------- */
void PairCoulStreitz::allocate()
{
allocated = 1;
int n = atom->ntypes;
memory->create(setflag,n+1,n+1,"pair:setflag");
memory->create(cutsq,n+1,n+1,"pair:cutsq");
memory->create(scale,n+1,n+1,"pair:scale");
memory->create(qeq_x,n+1,"pair:qeq_x");
memory->create(qeq_j,n+1,"pair:qeq_j");
memory->create(qeq_g,n+1,"pair:qeq_g");
memory->create(qeq_z,n+1,"pair:qeq_z");
memory->create(qeq_c,n+1,"pair:qeq_c");
map = new int[n+1];
}
/* ----------------------------------------------------------------------
global settings
------------------------------------------------------------------------- */
void PairCoulStreitz::settings(int narg, char **arg)
{
if (narg < 2) error->all(FLERR,"Illegal pair_style command");
cut_coul = force->numeric(FLERR,arg[0]);
if (strcmp(arg[1],"wolf") == 0){
kspacetype = 1;
g_wolf = force->numeric(FLERR,arg[2]);
} else if (strcmp(arg[1],"ewald") == 0){
ewaldflag = pppmflag = 1;
kspacetype = 2;
} else {
error->all(FLERR,"Illegal pair_style command");
}
}
/* ----------------------------------------------------------------------
set coeffs for one or more type pairs
------------------------------------------------------------------------- */
void PairCoulStreitz::coeff(int narg, char **arg)
{
int i,j,n;
if (!allocated) allocate();
if (narg != 3 + atom->ntypes)
error->all(FLERR,"Incorrect args for pair coefficients");
// insure I,J args are * *
if (strcmp(arg[0],"*") != 0 || strcmp(arg[1],"*") != 0)
error->all(FLERR,"Incorrect args for pair coefficients");
// read args that map atom types to elements in potential file
// map[i] = which element the Ith atom type is, -1 if NULL
// nelements = # of unique elements
// elements = list of element names
if (elements) {
for (i = 0; i < nelements; i++) delete [] elements[i];
delete [] elements;
}
elements = new char*[atom->ntypes];
for (i = 0; i < atom->ntypes; i++) elements[i] = NULL;
nelements = 0;
for (i = 3; i < narg; i++) {
if (strcmp(arg[i],"NULL") == 0) {
map[i-2] = -1;
continue;
}
for (j = 0; j < nelements; j++)
if (strcmp(arg[i],elements[j]) == 0) break;
map[i-2] = j;
if (j == nelements) {
n = strlen(arg[i]) + 1;
elements[j] = new char[n];
strcpy(elements[j],arg[i]);
nelements++;
}
}
// read potential file and initialize potential parameters
read_file(arg[2]);
setup();
n = atom->ntypes;
// clear setflag since coeff() called once with I,J = * *
for (int i = 1; i <= n; i++)
for (int j = i; j <= n; j++)
setflag[i][j] = 0;
// set setflag i,j for type pairs where both are mapped to elements
int count = 0;
for (int i = 1; i <= n; i++)
for (int j = i; j <= n; j++)
if (map[i] >= 0 && map[j] >= 0) {
scale[i][j] = 1.0;
setflag[i][j] = 1;
count++;
}
if (count == 0) error->all(FLERR,"Incorrect args for pair coefficients");
}
/* ----------------------------------------------------------------------
init specific to this pair style
------------------------------------------------------------------------- */
void PairCoulStreitz::init_style()
{
if (!atom->q_flag)
error->all(FLERR,"Pair style coul/streitz requires atom attribute q");
//neighbor->request(this);
int irequest = neighbor->request(this,instance_me);
neighbor->requests[irequest]->half = 0;
neighbor->requests[irequest]->full = 1;
cut_coulsq = cut_coul * cut_coul;
// insure use of KSpace long-range solver when ewald specified, set g_ewald
if (ewaldflag) {
if (force->kspace == NULL)
error->all(FLERR,"Pair style requires a KSpace style");
g_ewald = force->kspace->g_ewald;
}
// ptr to QEQ fix
//for (i = 0; i < modify->nfix; i++)
// if (strcmp(modify->fix[i]->style,"qeq") == 0) break;
//if (i < modify->nfix) fixqeq = (FixQEQ *) modify->fix[i];
//else fixqeq = NULL;
}
/* ----------------------------------------------------------------------
init for one type pair i,j and corresponding j,i
------------------------------------------------------------------------- */
double PairCoulStreitz::init_one(int i, int j)
{
scale[j][i] = scale[i][j];
if (setflag[i][j] == 0) error->all(FLERR,"All pair coeffs are not set");
return cut_coul;
}
/* ---------------------------------------------------------------------- */
void PairCoulStreitz::read_file(char *file)
{
int params_per_line = 6;
char **words = new char*[params_per_line+1];
memory->sfree(params);
params = NULL;
nparams = 0;
maxparam = 0;
// open file on proc 0
FILE *fp;
if (comm->me == 0) {
fp = fopen(file,"r");
if (fp == NULL) {
char str[128];
sprintf(str,"Cannot open coul/streitz potential file %s",file);
error->one(FLERR,str);
}
}
// read each line out of file, skipping blank lines or leading '#'
// store line of params if all 3 element tags are in element list
int n,nwords,ielement;
char line[MAXLINE],*ptr;
int eof = 0;
while (1) {
if (comm->me == 0) {
ptr = fgets(line,MAXLINE,fp);
if (ptr == NULL) {
eof = 1;
fclose(fp);
} else n = strlen(line) + 1;
}
MPI_Bcast(&eof,1,MPI_INT,0,world);
if (eof) break;
MPI_Bcast(&n,1,MPI_INT,0,world);
MPI_Bcast(line,n,MPI_CHAR,0,world);
// strip comment, skip line if blank
if ((ptr = strchr(line,'#'))) *ptr = '\0';
nwords = atom->count_words(line);
if (nwords == 0) continue;
// concatenate additional lines until have params_per_line words
while (nwords < params_per_line) {
n = strlen(line);
if (comm->me == 0) {
ptr = fgets(&line[n],MAXLINE-n,fp);
if (ptr == NULL) {
eof = 1;
fclose(fp);
} else n = strlen(line) + 1;
}
MPI_Bcast(&eof,1,MPI_INT,0,world);
if (eof) break;
MPI_Bcast(&n,1,MPI_INT,0,world);
MPI_Bcast(line,n,MPI_CHAR,0,world);
if ((ptr = strchr(line,'#'))) *ptr = '\0';
nwords = atom->count_words(line);
}
if (nwords != params_per_line)
error->all(FLERR,"Incorrect format in coul/streitz potential file");
// words = ptrs to all words in line
nwords = 0;
words[nwords++] = strtok(line," \t\n\r\f");
while ((words[nwords++] = strtok(NULL," \t\n\r\f"))) continue;
// ielement = 1st args
for (ielement = 0; ielement < nelements; ielement++)
if (strcmp(words[0],elements[ielement]) == 0) break;
if (ielement == nelements) continue;
// load up parameter settings and error check their values
if (nparams == maxparam) {
maxparam += DELTA;
params = (Param *) memory->srealloc(params,maxparam*sizeof(Param),
"pair:params");
}
params[nparams].ielement = ielement;
params[nparams].chi = atof(words[1]);
params[nparams].eta = atof(words[2]);
params[nparams].gamma = atof(words[3]);
params[nparams].zeta = atof(words[4]);
params[nparams].zcore = atof(words[5]);
// parameter sanity check
if (params[nparams].eta < 0.0 || params[nparams].zeta < 0.0 ||
params[nparams].zcore < 0.0 || params[nparams].gamma != 0.0 )
error->all(FLERR,"Illegal coul/streitz parameter");
nparams++;
}
delete [] words;
}
/* ---------------------------------------------------------------------- */
void PairCoulStreitz::setup()
{
int i,m,n;
// set elem2param
memory->destroy(elem2param);
memory->create(elem2param,nelements,"pair:elem2param");
for (i = 0; i < nelements; i++) {
n = -1;
for (m = 0; m < nparams; m++) {
if (i == params[m].ielement ) {
if (n >= 0) error->all(FLERR,"Potential file has duplicate entry");
n = m;
}
}
if (n < 0) error->all(FLERR,"Potential file is missing an entry");
elem2param[i] = n;
}
// Wolf sum self energy
if (kspacetype == 1) {
double a = g_wolf;
double r = cut_coul;
double ar = a*r;
woself = 0.50*erfc(ar)/r + a/MY_PIS; // kc constant not yet multiplied
dwoself = -(erfc(ar)/r/r + 2.0*a/MY_PIS*exp(-ar*ar)/r);
}
}
/* ---------------------------------------------------------------------- */
void PairCoulStreitz::compute(int eflag, int vflag)
{
int i, j, ii, jj, inum, jnum;
int itype, jtype, iparam_i,iparam_j;
int *ilist, *jlist, *numneigh, **firstneigh;
int *type = atom->type;
int nlocal = atom->nlocal;
int newton_pair = force->newton_pair;
double xtmp, ytmp, ztmp, ecoul, fpair;
double qi, qj, selfion, r, rsq, delr[3];
double zei, zej, zj, ci_jfi, dci_jfi, ci_fifj, dci_fifj;
double forcecoul, factor_coul;
double **x = atom->x;
double **f = atom->f;
double *q = atom->q;
double *special_coul = force->special_coul;
ecoul = 0.0;
selfion = fpair = 0.0;
ci_jfi = ci_fifj = dci_jfi = dci_fifj = 0.0;
forcecoul = 0.0;
if (eflag || vflag) ev_setup(eflag,vflag);
else evflag = vflag_fdotr = vflag_atom = 0;
inum = list->inum;
ilist = list->ilist;
numneigh = list->numneigh;
firstneigh = list->firstneigh;
// Wolf sum
if (kspacetype == 1) {
for (ii = 0; ii < inum; ii++) {
i = ilist[ii];
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
itype = map[type[i]];
iparam_i = elem2param[itype];
qi = q[i];
zei = params[iparam_i].zeta;
// self energy: ionization + wolf sum
selfion = self(&params[iparam_i],qi);
if (evflag) ev_tally(i,i,nlocal,0,0.0,selfion,0.0,0.0,0.0,0.0);
// two-body interaction
jlist = firstneigh[i];
jnum = numneigh[i];
for (jj = 0; jj < jnum; jj++) {
j = jlist[jj];
j &= NEIGHMASK;
jtype = map[type[j]];
iparam_j = elem2param[jtype];
qj = q[j];
zej = params[iparam_j].zeta;
zj = params[iparam_j].zcore;
factor_coul = special_coul[sbmask(j)];
delr[0] = xtmp - x[j][0];
delr[1] = ytmp - x[j][1];
delr[2] = ztmp - x[j][2];
rsq = delr[0]*delr[0] + delr[1]*delr[1] + delr[2]*delr[2];
if (rsq > cut_coulsq) continue;
r = sqrt(rsq);
// Streitz-Mintmire Coulomb integrals
coulomb_integral_wolf(zei, zej, r, ci_jfi, dci_jfi, ci_fifj, dci_fifj);
// Wolf Sum
wolf_sum(qi, qj, zj, r, ci_jfi, dci_jfi, ci_fifj, dci_fifj,
ecoul, forcecoul);
// Forces
fpair = -forcecoul / r;
f[i][0] += delr[0]*fpair;
f[i][1] += delr[1]*fpair;
f[i][2] += delr[2]*fpair;
if (newton_pair || j < nlocal) {
f[j][0] -= delr[0]*fpair;
f[j][1] -= delr[1]*fpair;
f[j][2] -= delr[2]*fpair;
}
if (evflag) ev_tally(i,j,nlocal,newton_pair,
0.0,ecoul,fpair,delr[0],delr[1],delr[2]);
}
}
// Ewald Sum
} else if (kspacetype == 2) {
for (ii = 0; ii < inum; ii++) {
i = ilist[ii];
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
itype = map[type[i]];
iparam_i = elem2param[itype];
qi = q[i];
zei = params[iparam_i].zeta;
// self ionizition energy, only on i atom
selfion = self(&params[iparam_i],qi);
if (evflag) ev_tally(i,i,nlocal,0,0.0,selfion,0.0,0.0,0.0,0.0);
// two-body interaction
jlist = firstneigh[i];
jnum = numneigh[i];
for (jj = 0; jj < jnum; jj++) {
j = jlist[jj];
j &= NEIGHMASK;
jtype = map[type[j]];
iparam_j = elem2param[jtype];
qj = q[j];
zej = params[iparam_j].zeta;
zj = params[iparam_j].zcore;
factor_coul = special_coul[sbmask(j)];
delr[0] = xtmp - x[j][0];
delr[1] = ytmp - x[j][1];
delr[2] = ztmp - x[j][2];
rsq = delr[0]*delr[0] + delr[1]*delr[1] + delr[2]*delr[2];
if (rsq > cut_coulsq) continue;
r = sqrt(rsq);
// Streitz-Mintmire Coulomb integrals
coulomb_integral_ewald(zei, zej, r, ci_jfi, dci_jfi, ci_fifj, dci_fifj);
// Ewald: real-space
ewald_sum(qi, qj, zj, r, ci_jfi, dci_jfi, ci_fifj, dci_fifj,
ecoul, forcecoul, factor_coul);
// Forces
fpair = -forcecoul / r;
f[i][0] += delr[0]*fpair;
f[i][1] += delr[1]*fpair;
f[i][2] += delr[2]*fpair;
if (newton_pair || j < nlocal) {
f[j][0] -= delr[0]*fpair;
f[j][1] -= delr[1]*fpair;
f[j][2] -= delr[2]*fpair;
}
if (evflag) ev_tally(i,j,nlocal,newton_pair,
0.0,ecoul,fpair,delr[0],delr[1],delr[2]);
}
}
}
if (vflag_fdotr) virial_fdotr_compute();
}
/* ---------------------------------------------------------------------- */
double PairCoulStreitz::self(Param *param, double qi)
{
double s1=param->chi, s2=param->eta;
double qqrd2e = force->qqrd2e;
if (kspacetype == 1) return 1.0*qi*(s1+qi*(0.50*s2 - qqrd2e*woself));
if (kspacetype == 2) return 1.0*qi*(s1+qi*(0.50*s2));
return 0.0;
}
/* ---------------------------------------------------------------------- */
void PairCoulStreitz::coulomb_integral_wolf(double zei, double zej, double r,
double &ci_jfi, double &dci_jfi, double &ci_fifj,
double &dci_fifj)
{
double rinv = 1.0/r;
double rinv2 = rinv*rinv;
double exp2zir = exp(-2.0*zei*r);
double zei2 = zei*zei;
double zei4 = zei2*zei2;
double zei6 = zei2*zei4;
double exp2zjr = exp(-2.0*zej*r);
double zej2 = zej*zej;
double zej4 = zej2*zej2;
double zej6 = zej2*zej4;
double sm1 = 11.0/8.0;
double sm2 = 3.00/4.0;
double sm3 = 1.00/6.0;
double e1, e2, e3, e4;
double rc = cut_coul;
double rcinv = 1.0/rc;
double rcinv2 = rcinv*rcinv;
double exp2zirsh = exp(-2.0*zei*rc);
double exp2zjrsh = exp(-2.0*zej*rc);
double eshift, fshift;
e1 = e2 = e3 = e4 = 0.0;
eshift = -zei*exp2zirsh - rcinv*exp2zirsh;
fshift = 2.0*zei2*exp2zirsh + rcinv2*exp2zirsh + 2.0*zei*rcinv*exp2zirsh;
ci_jfi = -zei*exp2zir - rinv*exp2zir - eshift - (r-rc)*fshift;
dci_jfi = 2.0*zei2*exp2zir + rinv2*exp2zir + 2.0*zei*rinv*exp2zir - fshift;
if (zei == zej) {
eshift = -exp2zirsh*(rcinv + zei*(sm1 + sm2*zei*rc + sm3*zei2*rc*rc));
fshift = exp2zirsh*(rcinv2 + 2.0*zei*rcinv + zei2*
(2.0 + 7.0/6.0*zei*rc + 1.0/3.0*zei2*rc*rc));
ci_fifj = -exp2zir*(rinv + zei*(sm1 + sm2*zei*r + sm3*zei2*r*r))
- eshift - (r-rc)*fshift;
dci_fifj = exp2zir*(rinv2 + 2.0*zei*rinv + zei2*
(2.0 + 7.0/6.0*zei*r + 1.0/3.0*zei2*r*r)) - fshift;
} else {
e1 = zei*zej4/((zei+zej)*(zei+zej)*(zei-zej)*(zei-zej));
e2 = zej*zei4/((zei+zej)*(zei+zej)*(zej-zei)*(zej-zei));
e3 = (3.0*zei2*zej4-zej6) /
((zei+zej)*(zei+zej)*(zei+zej)*(zei-zej)*(zei-zej)*(zei-zej));
e4 = (3.0*zej2*zei4-zei6) /
((zei+zej)*(zei+zej)*(zei+zej)*(zej-zei)*(zej-zei)*(zej-zei));
eshift = -exp2zirsh*(e1+e3/rc) - exp2zjrsh*(e2+e4/rc);
fshift = (exp2zirsh*(2.0*zei*(e1+e3/rc) + e3*rcinv2)
+ exp2zjrsh*(2.0*zej*(e2+e4/rc) + e4*rcinv2));
ci_fifj = -exp2zir*(e1+e3/r) - exp2zjr*(e2+e4/r)
- eshift - (r-rc)*fshift;
dci_fifj = (exp2zir*(2.0*zei*(e1+e3/r) + e3*rinv2) +
exp2zjr*(2.0*zej*(e2+e4/r) + e4*rinv2)) - fshift;
}
}
/* ---------------------------------------------------------------------- */
void PairCoulStreitz::wolf_sum(double qi, double qj, double zj, double r,
double ci_jfi, double dci_jfi, double ci_fifj,
double dci_fifj, double &etmp, double &ftmp)
{
double a = g_wolf;
double rc = cut_coul;
double qqrd2e = force->qqrd2e;
double erfcr = erfc(a*r);
double derfcr = exp(-a*a*r*r);
double erfcrc = erfc(a*rc);
double etmp1, etmp2, etmp3;
double ftmp1, ftmp2, ftmp3;
etmp = etmp1 = etmp2 = etmp3 = 0.0;
ftmp = ftmp1 = ftmp2 = ftmp3 = 0.0;
etmp1 = erfcr/r - erfcrc/rc;
etmp2 = qi * zj * (ci_jfi - ci_fifj);
etmp3 = qi * qj * 0.50 * (etmp1 + ci_fifj);
ftmp1 = -erfcr/r/r - 2.0*a/MY_PIS*derfcr/r - dwoself;
ftmp2 = qi * zj * (dci_jfi - dci_fifj);
ftmp3 = qi * qj * 0.50 * (ftmp1 + dci_fifj);
etmp = qqrd2e * (etmp2 + etmp3);
ftmp = qqrd2e * (ftmp2 + ftmp3);
}
/* ---------------------------------------------------------------------- */
void PairCoulStreitz::coulomb_integral_ewald(double zei, double zej, double r,
double &ci_jfi, double &dci_jfi, double &ci_fifj,
double &dci_fifj)
{
double rinv = 1.0/r;
double rinv2 = rinv*rinv;
double exp2zir = exp(-2.0*zei*r);
double zei2 = zei*zei;
double zei4 = zei2*zei2;
double zei6 = zei2*zei4;
double exp2zjr = exp(-2.0*zej*r);
double zej2 = zej*zej;
double zej4 = zej2*zej2;
double zej6 = zej2*zej4;
double sm1 = 11.0/8.0;
double sm2 = 3.00/4.0;
double sm3 = 1.00/6.0;
double e1, e2, e3, e4;
e1 = e2 = e3 = e4 = 0.0;
ci_jfi = -zei*exp2zir - rinv*exp2zir;
dci_jfi = 2.0*zei2*exp2zir + rinv2*exp2zir + 2.0*zei*rinv*exp2zir;
if (zei == zej) {
ci_fifj = -exp2zir*(rinv + zei*(sm1 + sm2*zei*r + sm3*zei2*r*r));
dci_fifj = exp2zir*(rinv2 + 2.0*zei*rinv +
zei2*(2.0 + 7.0/6.0*zei*r + 1.0/3.0*zei2*r*r));
} else {
e1 = zei*zej4/((zei+zej)*(zei+zej)*(zei-zej)*(zei-zej));
e2 = zej*zei4/((zei+zej)*(zei+zej)*(zej-zei)*(zej-zei));
e3 = (3.0*zei2*zej4-zej6) /
((zei+zej)*(zei+zej)*(zei+zej)*(zei-zej)*(zei-zej)*(zei-zej));
e4 = (3.0*zej2*zei4-zei6) /
((zei+zej)*(zei+zej)*(zei+zej)*(zej-zei)*(zej-zei)*(zej-zei));
ci_fifj = -exp2zir*(e1+e3/r) - exp2zjr*(e2+e4/r);
dci_fifj = (exp2zir*(2.0*zei*(e1+e3/r) + e3*rinv2)
+ exp2zjr*(2.0*zej*(e2+e4/r) + e4*rinv2));
}
}
/* ---------------------------------------------------------------------- */
void PairCoulStreitz::ewald_sum(double qi, double qj, double zj, double r,
double ci_jfi, double dci_jfi, double ci_fifj,
double dci_fifj, double &etmp, double &ftmp, double fac)
{
double etmp1, etmp2, etmp3, etmp4;
double ftmp1, ftmp2, ftmp3, ftmp4;
double a = g_ewald;
double qqrd2e = force->qqrd2e;
double erfcr = erfc(a*r);
double derfcr = exp(-a*a*r*r);
etmp = ftmp = 0.0;
etmp1 = etmp2 = etmp3 = etmp4 = 0.0;
ftmp1 = ftmp2 = ftmp3 = ftmp4 = 0.0;
etmp1 = qi * zj * (ci_jfi - ci_fifj);
etmp2 = qi * qj * 0.50 * ci_fifj;
etmp3 = qqrd2e * (etmp1 + etmp2);
etmp4 = qqrd2e * 0.50*qi*qj/r;
ftmp1 = qi * zj * (dci_jfi - dci_fifj);
ftmp2 = qi * qj * 0.50 * dci_fifj;
ftmp3 = qqrd2e * (ftmp1 + ftmp2);
ftmp4 = etmp4 * (erfcr + 2.0/MY_PIS*a*r*derfcr);
etmp = erfcr*etmp4;
if (fac < 1.0) {
etmp -= (1.0-fac)*etmp4;
ftmp4 -= (1.0-fac)*etmp4;
}
etmp += etmp3;
ftmp = ftmp3 - ftmp4/r;
}
/* ----------------------------------------------------------------------
memory usage of local atom-based arrays
------------------------------------------------------------------------- */
double PairCoulStreitz::memory_usage()
{
double bytes = maxeatom * sizeof(double);
bytes += maxvatom*6 * sizeof(double);
bytes += nmax * sizeof(int);
bytes += MAXNEIGH * nmax * sizeof(int);
return bytes;
}
/* ---------------------------------------------------------------------- */
void *PairCoulStreitz::extract(const char *str, int &dim)
{
if (strcmp(str,"cut_coul") == 0) {
dim = 0;
return (void *) &cut_coul;
}
if (strcmp(str,"scale") == 0) {
dim = 2;
return (void *) scale;
}
if (strcmp(str,"chi") == 0 && qeq_x) {
dim = 1;
for (int i = 1; i <= atom->ntypes; i++)
if (map[i] >= 0) qeq_x[i] = params[map[i]].chi;
else qeq_x[i] = 0.0;
return (void *) qeq_x;
}
if (strcmp(str,"eta") == 0 && qeq_j) {
dim = 1;
for (int i = 1; i <= atom->ntypes; i++)
if (map[i] >= 0) qeq_j[i] = params[map[i]].eta;
else qeq_j[i] = 0.0;
return (void *) qeq_j;
}
if (strcmp(str,"gamma") == 0 && qeq_g) {
dim = 1;
for (int i = 1; i <= atom->ntypes; i++)
if (map[i] >= 0) qeq_g[i] = params[map[i]].gamma;
else qeq_g[i] = 0.0;
return (void *) qeq_g;
}
if (strcmp(str,"zeta") == 0 && qeq_z) {
dim = 1;
for (int i = 1; i <= atom->ntypes; i++)
if (map[i] >= 0) qeq_z[i] = params[map[i]].zeta;
else qeq_z[i] = 0.0;
return (void *) qeq_z;
}
if (strcmp(str,"zcore") == 0 && qeq_c) {
dim = 1;
for (int i = 1; i <= atom->ntypes; i++)
if (map[i] >= 0) qeq_c[i] = params[map[i]].zcore;
else qeq_c[i] = 0.0;
return (void *) qeq_c;
}
if (strcmp(str,"kspacetype") == 0) {
dim = 0;
return (void *) &kspacetype;
}
if (strcmp(str,"alpha") == 0) {
dim = 0;
if (kspacetype == 1) return (void *) &g_wolf;
if (kspacetype == 2) return (void *) &g_ewald;
}
return NULL;
}

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