pair style born/coul/dsf added with its coreshell version

src/.gitignore

@@ -976,6 +976,8 @@
 /fix_ttm_mod.h
 /pair_born_coul_long_cs.cpp
 /pair_born_coul_long_cs.h
+/pair_born_coul_dsf_cs.cpp
+/pair_born_coul_dsf_cs.h
 /pair_buck_coul_long_cs.cpp
 /pair_buck_coul_long_cs.h
 /pair_coul_long_cs.cpp

src/CORESHELL/Install.sh

@@ -31,8 +31,10 @@ action () {
 action compute_temp_cs.cpp
 action compute_temp_cs.h
 action pair_born_coul_long_cs.cpp pair_born_coul_long.cpp
+action pair_born_coul_dsf_cs.cpp pair_born_coul_dsf.cpp
 action pair_buck_coul_long_cs.cpp pair_buck_coul_long.cpp
 action pair_born_coul_long_cs.h pair_born_coul_long.h
+action pair_born_coul_dsf_cs.h pair_born_coul_dsf.h
 action pair_buck_coul_long_cs.h pair_buck_coul_long.h
 action pair_coul_long_cs.cpp pair_coul_long.cpp
 action pair_coul_long_cs.h pair_coul_long.h

src/CORESHELL/pair_born_coul_dsf_cs.cpp

@@ -0,0 +1,162 @@
+/* ----------------------------------------------------------------------
+   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: Ariel Lozano (arielzn@gmail.com)
+   References: Fennell and Gezelter, JCP 124, 234104 (2006)
+------------------------------------------------------------------------- */
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "pair_born_coul_dsf_cs.h"
+#include "atom.h"
+#include "comm.h"
+#include "force.h"
+#include "neighbor.h"
+#include "neigh_list.h"
+#include "math_const.h"
+#include "memory.h"
+#include "error.h"
+#include "math_special.h"
+
+using namespace LAMMPS_NS;
+using namespace MathConst;
+
+#define EPSILON 1.0e-20
+
+
+/* ---------------------------------------------------------------------- */
+
+PairBornCoulDSFCS::PairBornCoulDSFCS(LAMMPS *lmp) : PairBornCoulDSF(lmp)
+{
+  writedata = 1;
+  single_enable = 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void PairBornCoulDSFCS::compute(int eflag, int vflag)
+{
+  int i,j,ii,jj,inum,jnum,itype,jtype;
+  double qtmp,xtmp,ytmp,ztmp,delx,dely,delz,evdwl,ecoul,fpair;
+  double r,rsq,r2inv,r6inv,forcecoul,forceborn,factor_coul,factor_lj;
+  double prefactor,erfcc,erfcd,arg;
+  double rexp;
+  int *ilist,*jlist,*numneigh,**firstneigh;
+
+  evdwl = ecoul = 0.0;
+  if (eflag || vflag) ev_setup(eflag,vflag);
+  else evflag = vflag_fdotr = 0;
+
+  double **x = atom->x;
+  double **f = atom->f;
+  double *q = atom->q;
+  int *type = atom->type;
+  int nlocal = atom->nlocal;
+  double *special_lj = force->special_lj;
+  double *special_coul = force->special_coul;
+  int newton_pair = force->newton_pair;
+  double qqrd2e = force->qqrd2e;
+
+  inum = list->inum;
+  ilist = list->ilist;
+  numneigh = list->numneigh;
+  firstneigh = list->firstneigh;
+
+  // loop over neighbors of my atoms
+
+  for (ii = 0; ii < inum; ii++) {
+    i = ilist[ii];
+    qtmp = q[i];
+    xtmp = x[i][0];
+    ytmp = x[i][1];
+    ztmp = x[i][2];
+    itype = type[i];
+    jlist = firstneigh[i];
+    jnum = numneigh[i];
+
+  // self coulombic energy
+    if (eflag) {
+      double e_self = -(e_shift/2.0 + alpha/MY_PIS) * qtmp*qtmp*qqrd2e;
+      ev_tally(i,i,nlocal,0,0.0,e_self,0.0,0.0,0.0,0.0);
+    }
+
+    for (jj = 0; jj < jnum; jj++) {
+      j = jlist[jj];
+      factor_lj = special_lj[sbmask(j)];
+      factor_coul = special_coul[sbmask(j)];
+      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];
+
+      if (rsq < cutsq[itype][jtype]) {
+        rsq += EPSILON; // Add Epsilon for case: r = 0; Interaction must be removed by special bond;
+        r2inv = 1.0/rsq;
+
+        if (rsq < cut_coulsq) {
+          r = sqrt(rsq);
+          prefactor = qqrd2e*qtmp*q[j] / r;
+	  arg = alpha * r ;
+          erfcd = MathSpecial::expmsq(arg);
+          erfcc = MathSpecial::my_erfcx(arg) * erfcd;
+          forcecoul = prefactor * (erfcc/r + 2.0*alpha/MY_PIS * erfcd +
+                                   r*f_shift) * r;
+          if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*prefactor;
+        } else forcecoul = 0.0;
+
+        if (rsq < cut_ljsq[itype][jtype]) {
+          r6inv = r2inv*r2inv*r2inv;
+          r = sqrt(rsq);
+          rexp = exp((sigma[itype][jtype]-r)*rhoinv[itype][jtype]);
+          forceborn = born1[itype][jtype]*r*rexp - born2[itype][jtype]*r6inv
+            + born3[itype][jtype]*r2inv*r6inv;
+        } else forceborn = 0.0;
+
+        fpair = (forcecoul + factor_lj*forceborn) * r2inv;
+
+        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) {
+          if (rsq < cut_coulsq) {
+            ecoul = prefactor * (erfcc - r*e_shift - rsq*f_shift);
+            if (factor_coul < 1.0) ecoul -= (1.0-factor_coul)*prefactor;
+          } else ecoul = 0.0;
+          if (rsq < cut_ljsq[itype][jtype]) {
+            evdwl = a[itype][jtype]*rexp - c[itype][jtype]*r6inv +
+              d[itype][jtype]*r6inv*r2inv - offset[itype][jtype];
+            evdwl *= factor_lj;
+          } else evdwl = 0.0;
+        }
+
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,
+                             evdwl,ecoul,fpair,delx,dely,delz);
+      }
+    }
+  }
+
+  if (vflag_fdotr) virial_fdotr_compute();
+}
+

src/CORESHELL/pair_born_coul_dsf_cs.h

@@ -0,0 +1,59 @@
+/* -*- c++ -*- ----------------------------------------------------------
+   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.
+------------------------------------------------------------------------- */
+
+#ifdef PAIR_CLASS
+
+PairStyle(born/coul/dsf/cs,PairBornCoulDSFCS)
+
+#else
+
+#ifndef LMP_PAIR_BORN_COUL_DSF_CS_H
+#define LMP_PAIR_BORN_COUL_DSF_CS_H
+
+#include "pair_born_coul_dsf.h"
+
+namespace LAMMPS_NS {
+
+class PairBornCoulDSFCS : public PairBornCoulDSF {
+ public:
+  PairBornCoulDSFCS(class LAMMPS *);
+  virtual void compute(int, int);
+};
+
+}
+
+#endif
+#endif
+
+/* ERROR/WARNING messages:
+
+E: Illegal ... command
+
+Self-explanatory.  Check the input script syntax and compare to the
+documentation for the command.  You can use -echo screen as a
+command-line option when running LAMMPS to see the offending line.
+
+E: Incorrect args for pair coefficients
+
+Self-explanatory.  Check the input script or data file.
+
+E: Pair style born/coul/dsf requires atom attribute q
+
+The atom style defined does not have this attribute.
+
+E: All pair coeffs are not set
+
+All pair coefficients must be set in the data file or by the
+pair_coeff command before running a simulation.
+
+*/

src/pair_born_coul_dsf.cpp

@@ -0,0 +1,494 @@
+/* ----------------------------------------------------------------------
+   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: Ariel Lozano (arielzn@gmail.com)
+   References: Fennell and Gezelter, JCP 124, 234104 (2006)
+------------------------------------------------------------------------- */
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "pair_born_coul_dsf.h"
+#include "atom.h"
+#include "comm.h"
+#include "force.h"
+#include "neighbor.h"
+#include "neigh_list.h"
+#include "math_const.h"
+#include "memory.h"
+#include "error.h"
+#include "math_special.h"
+
+using namespace LAMMPS_NS;
+using namespace MathConst;
+
+/* ---------------------------------------------------------------------- */
+
+PairBornCoulDSF::PairBornCoulDSF(LAMMPS *lmp) : Pair(lmp)
+{
+  writedata = 1;
+  single_enable = 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+PairBornCoulDSF::~PairBornCoulDSF()
+{
+  if (allocated) {
+    memory->destroy(setflag);
+    memory->destroy(cutsq);
+
+    memory->destroy(cut_lj);
+    memory->destroy(cut_ljsq);
+    memory->destroy(a);
+    memory->destroy(rho);
+    memory->destroy(sigma);
+    memory->destroy(c);
+    memory->destroy(d);
+    memory->destroy(rhoinv);
+    memory->destroy(born1);
+    memory->destroy(born2);
+    memory->destroy(born3);
+    memory->destroy(offset);
+  }
+}
+
+/* ---------------------------------------------------------------------- */
+
+void PairBornCoulDSF::compute(int eflag, int vflag)
+{
+  int i,j,ii,jj,inum,jnum,itype,jtype;
+  double qtmp,xtmp,ytmp,ztmp,delx,dely,delz,evdwl,ecoul,fpair;
+  double r,rsq,r2inv,r6inv,forcecoul,forceborn,factor_coul,factor_lj;
+  double prefactor,erfcc,erfcd,arg;
+  double rexp;
+  int *ilist,*jlist,*numneigh,**firstneigh;
+
+  evdwl = ecoul = 0.0;
+  if (eflag || vflag) ev_setup(eflag,vflag);
+  else evflag = vflag_fdotr = 0;
+
+  double **x = atom->x;
+  double **f = atom->f;
+  double *q = atom->q;
+  int *type = atom->type;
+  int nlocal = atom->nlocal;
+  double *special_lj = force->special_lj;
+  double *special_coul = force->special_coul;
+  int newton_pair = force->newton_pair;
+  double qqrd2e = force->qqrd2e;
+
+  inum = list->inum;
+  ilist = list->ilist;
+  numneigh = list->numneigh;
+  firstneigh = list->firstneigh;
+
+  // loop over neighbors of my atoms
+
+  for (ii = 0; ii < inum; ii++) {
+    i = ilist[ii];
+    qtmp = q[i];
+    xtmp = x[i][0];
+    ytmp = x[i][1];
+    ztmp = x[i][2];
+    itype = type[i];
+    jlist = firstneigh[i];
+    jnum = numneigh[i];
+
+  // self coulombic energy
+    if (eflag) {
+      double e_self = -(e_shift/2.0 + alpha/MY_PIS) * qtmp*qtmp*qqrd2e;
+      ev_tally(i,i,nlocal,0,0.0,e_self,0.0,0.0,0.0,0.0);
+    }
+
+    for (jj = 0; jj < jnum; jj++) {
+      j = jlist[jj];
+      factor_lj = special_lj[sbmask(j)];
+      factor_coul = special_coul[sbmask(j)];
+      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];
+
+      if (rsq < cutsq[itype][jtype]) {
+        r2inv = 1.0/rsq;
+
+        if (rsq < cut_coulsq) {
+          r = sqrt(rsq);
+          prefactor = qqrd2e*qtmp*q[j]/r;
+	  arg = alpha * r ;
+          erfcd = MathSpecial::expmsq(arg);
+          erfcc = MathSpecial::my_erfcx(arg) * erfcd;
+          forcecoul = prefactor * (erfcc/r + 2.0*alpha/MY_PIS * erfcd +
+                                   r*f_shift) * r;
+          if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*prefactor;
+        } else forcecoul = 0.0;
+
+        if (rsq < cut_ljsq[itype][jtype]) {
+          r6inv = r2inv*r2inv*r2inv;
+          r = sqrt(rsq);
+          rexp = exp((sigma[itype][jtype]-r)*rhoinv[itype][jtype]);
+          forceborn = born1[itype][jtype]*r*rexp - born2[itype][jtype]*r6inv
+            + born3[itype][jtype]*r2inv*r6inv;
+        } else forceborn = 0.0;
+
+        fpair = (forcecoul + factor_lj*forceborn) * r2inv;
+
+        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) {
+          if (rsq < cut_coulsq) {
+            ecoul = prefactor * (erfcc - r*e_shift - rsq*f_shift);
+            if (factor_coul < 1.0) ecoul -= (1.0-factor_coul)*prefactor;
+          } else ecoul = 0.0;
+          if (rsq < cut_ljsq[itype][jtype]) {
+            evdwl = a[itype][jtype]*rexp - c[itype][jtype]*r6inv +
+              d[itype][jtype]*r6inv*r2inv - offset[itype][jtype];
+            evdwl *= factor_lj;
+          } else evdwl = 0.0;
+        }
+
+        if (evflag) ev_tally(i,j,nlocal,newton_pair,
+                             evdwl,ecoul,fpair,delx,dely,delz);
+      }
+    }
+  }
+
+  if (vflag_fdotr) virial_fdotr_compute();
+}
+
+/* ----------------------------------------------------------------------
+   allocate all arrays
+------------------------------------------------------------------------- */
+
+void PairBornCoulDSF::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_lj,n+1,n+1,"pair:cut_lj");
+  memory->create(cut_ljsq,n+1,n+1,"pair:cut_ljsq");
+  memory->create(a,n+1,n+1,"pair:a");
+  memory->create(rho,n+1,n+1,"pair:rho");
+  memory->create(sigma,n+1,n+1,"pair:sigma");
+  memory->create(c,n+1,n+1,"pair:c");
+  memory->create(d,n+1,n+1,"pair:d");
+  memory->create(rhoinv,n+1,n+1,"pair:rhoinv");
+  memory->create(born1,n+1,n+1,"pair:born1");
+  memory->create(born2,n+1,n+1,"pair:born2");
+  memory->create(born3,n+1,n+1,"pair:born3");
+  memory->create(offset,n+1,n+1,"pair:offset");
+}
+
+/* ----------------------------------------------------------------------
+   global settings
+------------------------------------------------------------------------- */
+
+void PairBornCoulDSF::settings(int narg, char **arg)
+{
+  if (narg < 2 || narg > 3) error->all(FLERR,"Illegal pair_style command");
+
+  alpha = force->numeric(FLERR,arg[0]);
+  cut_lj_global = force->numeric(FLERR,arg[1]);
+  if (narg == 2) cut_coul = cut_lj_global;
+  else cut_coul = force->numeric(FLERR,arg[2]);
+
+  if (allocated) {
+    int i,j;
+    for (i = 1; i <= atom->ntypes; i++)
+      for (j = i+1; j <= atom->ntypes; j++)
+        if (setflag[i][j])
+          cut_lj[i][j] = cut_lj_global;
+  }
+}
+
+/* ----------------------------------------------------------------------
+   set coeffs for one or more type pairs
+------------------------------------------------------------------------- */
+
+void PairBornCoulDSF::coeff(int narg, char **arg)
+{
+  if (narg < 7 || narg > 8)
+    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 a_one = force->numeric(FLERR,arg[2]);
+  double rho_one = force->numeric(FLERR,arg[3]);
+  double sigma_one = force->numeric(FLERR,arg[4]);
+  if (rho_one <= 0) error->all(FLERR,"Incorrect args for pair coefficients");
+  double c_one = force->numeric(FLERR,arg[5]);
+  double d_one = force->numeric(FLERR,arg[6]);
+
+  double cut_lj_one = cut_lj_global;
+  if (narg == 8) cut_lj_one = force->numeric(FLERR,arg[7]);
+
+  int count = 0;
+  for (int i = ilo; i <= ihi; i++) {
+    for (int j = MAX(jlo,i); j <= jhi; j++) {
+      a[i][j] = a_one;
+      rho[i][j] = rho_one;
+      sigma[i][j] = sigma_one;
+      c[i][j] = c_one;
+      d[i][j] = d_one;
+      cut_lj[i][j] = cut_lj_one;
+      setflag[i][j] = 1;
+      count++;
+    }
+  }
+
+  if (count == 0) error->all(FLERR,"Incorrect args for pair coefficients");
+}
+
+/* ----------------------------------------------------------------------
+   init specific to this pair style
+------------------------------------------------------------------------- */
+
+void PairBornCoulDSF::init_style()
+{
+  if (!atom->q_flag)
+    error->all(FLERR,"Pair style born/coul/dsf requires atom attribute q");
+
+  neighbor->request(this,instance_me);
+
+  cut_coulsq = cut_coul * cut_coul;
+  double erfcc = erfc(alpha*cut_coul);
+  double erfcd = exp(-alpha*alpha*cut_coul*cut_coul);
+  f_shift = -(erfcc/cut_coulsq + 2.0/MY_PIS*alpha*erfcd/cut_coul);
+  e_shift = erfcc/cut_coul - f_shift*cut_coul;
+}
+
+/* ----------------------------------------------------------------------
+   init for one type pair i,j and corresponding j,i
+------------------------------------------------------------------------- */
+
+double PairBornCoulDSF::init_one(int i, int j)
+{
+  if (setflag[i][j] == 0) error->all(FLERR,"All pair coeffs are not set");
+
+  double cut = MAX(cut_lj[i][j],cut_coul);
+  cut_ljsq[i][j] = cut_lj[i][j] * cut_lj[i][j];
+
+  rhoinv[i][j] = 1.0/rho[i][j];
+  born1[i][j] = a[i][j]/rho[i][j];
+  born2[i][j] = 6.0*c[i][j];
+  born3[i][j] = 8.0*d[i][j];
+
+  if (offset_flag) {
+    double rexp = exp((sigma[i][j]-cut_lj[i][j])*rhoinv[i][j]);
+    offset[i][j] = a[i][j]*rexp - c[i][j]/pow(cut_lj[i][j],6.0)
+      + d[i][j]/pow(cut_lj[i][j],8.0);
+  } else offset[i][j] = 0.0;
+
+  cut_ljsq[j][i] = cut_ljsq[i][j];
+  a[j][i] = a[i][j];
+  c[j][i] = c[i][j];
+  d[j][i] = d[i][j];
+  rhoinv[j][i] = rhoinv[i][j];
+  sigma[j][i] = sigma[i][j];
+  born1[j][i] = born1[i][j];
+  born2[j][i] = born2[i][j];
+  born3[j][i] = born3[i][j];
+  offset[j][i] = offset[i][j];
+
+  return cut;
+}
+
+/* ----------------------------------------------------------------------
+  proc 0 writes to restart file
+------------------------------------------------------------------------- */
+
+void PairBornCoulDSF::write_restart(FILE *fp)
+{
+  write_restart_settings(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(&a[i][j],sizeof(double),1,fp);
+        fwrite(&rho[i][j],sizeof(double),1,fp);
+        fwrite(&sigma[i][j],sizeof(double),1,fp);
+        fwrite(&c[i][j],sizeof(double),1,fp);
+        fwrite(&d[i][j],sizeof(double),1,fp);
+        fwrite(&cut_lj[i][j],sizeof(double),1,fp);
+      }
+    }
+}
+
+/* ----------------------------------------------------------------------
+  proc 0 reads from restart file, bcasts
+------------------------------------------------------------------------- */
+
+void PairBornCoulDSF::read_restart(FILE *fp)
+{
+  read_restart_settings(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(&a[i][j],sizeof(double),1,fp);
+          fread(&rho[i][j],sizeof(double),1,fp);
+          fread(&sigma[i][j],sizeof(double),1,fp);
+          fread(&c[i][j],sizeof(double),1,fp);
+          fread(&d[i][j],sizeof(double),1,fp);
+          fread(&cut_lj[i][j],sizeof(double),1,fp);
+        }
+        MPI_Bcast(&a[i][j],1,MPI_DOUBLE,0,world);
+        MPI_Bcast(&rho[i][j],1,MPI_DOUBLE,0,world);
+        MPI_Bcast(&sigma[i][j],1,MPI_DOUBLE,0,world);
+        MPI_Bcast(&c[i][j],1,MPI_DOUBLE,0,world);
+        MPI_Bcast(&d[i][j],1,MPI_DOUBLE,0,world);
+        MPI_Bcast(&cut_lj[i][j],1,MPI_DOUBLE,0,world);
+      }
+    }
+}
+
+/* ----------------------------------------------------------------------
+  proc 0 writes to restart file
+------------------------------------------------------------------------- */
+
+void PairBornCoulDSF::write_restart_settings(FILE *fp)
+{
+  fwrite(&alpha,sizeof(double),1,fp);
+  fwrite(&cut_lj_global,sizeof(double),1,fp);
+  fwrite(&cut_coul,sizeof(double),1,fp);
+  fwrite(&offset_flag,sizeof(int),1,fp);
+  fwrite(&mix_flag,sizeof(int),1,fp);
+}
+
+/* ----------------------------------------------------------------------
+  proc 0 reads from restart file, bcasts
+------------------------------------------------------------------------- */
+
+void PairBornCoulDSF::read_restart_settings(FILE *fp)
+{
+  if (comm->me == 0) {
+    fread(&alpha,sizeof(double),1,fp);
+    fread(&cut_lj_global,sizeof(double),1,fp);
+    fread(&cut_coul,sizeof(double),1,fp);
+    fread(&offset_flag,sizeof(int),1,fp);
+    fread(&mix_flag,sizeof(int),1,fp);
+  }
+  MPI_Bcast(&alpha,1,MPI_DOUBLE,0,world);
+  MPI_Bcast(&cut_lj_global,1,MPI_DOUBLE,0,world);
+  MPI_Bcast(&cut_coul,1,MPI_DOUBLE,0,world);
+  MPI_Bcast(&offset_flag,1,MPI_INT,0,world);
+  MPI_Bcast(&mix_flag,1,MPI_INT,0,world);
+}
+
+/* ----------------------------------------------------------------------
+   proc 0 writes to data file
+------------------------------------------------------------------------- */
+
+void PairBornCoulDSF::write_data(FILE *fp)
+{
+  for (int i = 1; i <= atom->ntypes; i++)
+    fprintf(fp,"%d %g %g %g %g %g\n",i,
+            a[i][i],rho[i][i],sigma[i][i],c[i][i],d[i][i]);
+}
+
+/* ----------------------------------------------------------------------
+   proc 0 writes all pairs to data file
+------------------------------------------------------------------------- */
+
+void PairBornCoulDSF::write_data_all(FILE *fp)
+{
+  for (int i = 1; i <= atom->ntypes; i++)
+    for (int j = i; j <= atom->ntypes; j++)
+      fprintf(fp,"%d %d %g %g %g %g %g %g\n",i,j,
+              a[i][j],rho[i][j],sigma[i][j],c[i][j],d[i][j],cut_lj[i][j]);
+}
+
+/* ----------------------------------------------------------------------
+   only the pair part is calculated here
+------------------------------------------------------------------------- */
+
+double PairBornCoulDSF::single(int i, int j, int itype, int jtype,
+                                double rsq,
+                                double factor_coul, double factor_lj,
+                                double &fforce)
+{
+  double r2inv,r6inv,r,prefactor,rexp;
+  double forcecoul,forceborn,phicoul,phiborn;
+  double erfcc,erfcd,arg;
+
+  r2inv = 1.0/rsq;
+
+  if (rsq < cut_coulsq) {
+    r = sqrt(rsq);
+    prefactor = factor_coul * force->qqrd2e * atom->q[i]*atom->q[j]/r;
+
+    arg = alpha * r ;
+    erfcd = MathSpecial::expmsq(arg);
+    erfcc = MathSpecial::my_erfcx(arg) * erfcd;
+
+    forcecoul = prefactor * (erfcc/r + 2.0*alpha/MY_PIS*erfcd +
+      r*f_shift) * r;
+
+    if (factor_coul < 1.0) forcecoul -= (1.0-factor_coul)*prefactor;
+  } else forcecoul = 0.0;
+
+  if (rsq < cut_ljsq[itype][jtype]) {
+    r6inv = r2inv*r2inv*r2inv;
+    r = sqrt(rsq);
+    rexp = exp(-r*rhoinv[itype][jtype]);
+    forceborn = born1[itype][jtype]*r*rexp - born2[itype][jtype]*r6inv
+      + born3[itype][jtype]*r2inv*r6inv;
+  } else forceborn = 0.0;
+
+  fforce = (forcecoul + factor_lj*forceborn) * r2inv;
+
+  double eng = 0.0;
+  if (rsq < cut_coulsq) {
+    phicoul = prefactor * (erfcc - r*e_shift - rsq*f_shift);
+    if (factor_coul < 1.0) phicoul -= (1.0-factor_coul)*prefactor;
+    eng += phicoul;
+  }
+  if (rsq < cut_ljsq[itype][jtype]) {
+    phiborn = a[itype][jtype]*rexp - c[itype][jtype]*r6inv
+      + d[itype][jtype]*r2inv*r6inv - offset[itype][jtype];
+    eng += factor_lj*phiborn;
+  }
+  return eng;
+}

src/pair_born_coul_dsf.h

@@ -0,0 +1,81 @@
+/* -*- c++ -*- ----------------------------------------------------------
+   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.
+------------------------------------------------------------------------- */
+
+#ifdef PAIR_CLASS
+
+PairStyle(born/coul/dsf,PairBornCoulDSF)
+
+#else
+
+#ifndef LMP_PAIR_BORN_COUL_DSF_H
+#define LMP_PAIR_BORN_COUL_DSF_H
+
+#include "pair.h"
+
+namespace LAMMPS_NS {
+
+class PairBornCoulDSF : public Pair {
+ public:
+  PairBornCoulDSF(class LAMMPS *);
+  virtual ~PairBornCoulDSF();
+  virtual void compute(int, int);
+  void settings(int, char **);
+  void coeff(int, char **);
+  void init_style();
+  double init_one(int, int);
+  void write_restart(FILE *);
+  void read_restart(FILE *);
+  void write_restart_settings(FILE *);
+  void read_restart_settings(FILE *);
+  void write_data(FILE *);
+  void write_data_all(FILE *);
+  double single(int, int, int, int, double, double, double, double &);
+
+ protected:
+  double cut_lj_global,alpha;
+  double **cut_lj,**cut_ljsq;
+  double cut_coul,cut_coulsq;
+  double **a,**rho,**sigma,**c,**d;
+  double **rhoinv,**born1,**born2,**born3,**offset;
+  double f_shift,e_shift;
+
+  void allocate();
+};
+
+}
+
+#endif
+#endif
+
+/* ERROR/WARNING messages:
+
+E: Illegal ... command
+
+Self-explanatory.  Check the input script syntax and compare to the
+documentation for the command.  You can use -echo screen as a
+command-line option when running LAMMPS to see the offending line.
+
+E: Incorrect args for pair coefficients
+
+Self-explanatory.  Check the input script or data file.
+
+E: Pair style born/coul/dsf requires atom attribute q
+
+The atom style defined does not have this attribute.
+
+E: All pair coeffs are not set
+
+All pair coefficients must be set in the data file or by the
+pair_coeff command before running a simulation.
+
+*/