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lammps/src/pair_zero.cpp
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pair_zero.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: Carsten Svaneborg (SDU)
------------------------------------------------------------------------- */
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "pair_zero.h"
#include "atom.h"
#include "comm.h"
#include "force.h"
#include "memory.h"
#include "error.h"
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
PairZero::PairZero(LAMMPS *lmp) : Pair(lmp) {
coeffflag=1;
writedata=1;
}
/* ---------------------------------------------------------------------- */
PairZero::~PairZero()
{
if (allocated) {
memory->destroy(setflag);
memory->destroy(cutsq);
memory->destroy(cut);
}
}
/* ---------------------------------------------------------------------- */
void PairZero::compute(int eflag, int vflag)
{
if (eflag || vflag) ev_setup(eflag,vflag);
else evflag = vflag_fdotr = 0;
if (vflag_fdotr) virial_fdotr_compute();
}
/* ----------------------------------------------------------------------
allocate all arrays
------------------------------------------------------------------------- */
void PairZero::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");
}
/* ----------------------------------------------------------------------
global settings
------------------------------------------------------------------------- */
void PairZero::settings(int narg, char **arg)
{
if ((narg != 1) && (narg != 2))
error->all(FLERR,"Illegal pair_style command");
cut_global = force->numeric(FLERR,arg[0]);
if (narg == 2) {
if (strcmp("nocoeff",arg[1]) == 0) coeffflag=0;
else error->all(FLERR,"Illegal pair_style command");
}
// reset cutoffs that have been explicitly set
if (allocated) {
int i,j;
for (i = 1; i <= atom->ntypes; i++)
for (j = i+1; j <= atom->ntypes; j++)
cut[i][j] = cut_global;
}
}
/* ----------------------------------------------------------------------
set coeffs for one or more type pairs
------------------------------------------------------------------------- */
void PairZero::coeff(int narg, char **arg)
{
if ((narg < 2) || (coeffflag && narg > 3))
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 cut_one = cut_global;
if (coeffflag && (narg == 3)) cut_one = force->numeric(FLERR,arg[2]);
int count = 0;
for (int i = ilo; i <= ihi; i++) {
for (int j = MAX(jlo,i); j <= jhi; j++) {
cut[i][j] = cut_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 PairZero::init_one(int i, int j)
{
if (setflag[i][j] == 0) {
cut[i][j] = mix_distance(cut[i][i],cut[j][j]);
}
return cut[i][j];
}
/* ----------------------------------------------------------------------
proc 0 writes to restart file
------------------------------------------------------------------------- */
void PairZero::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(&cut[i][j],sizeof(double),1,fp);
}
}
}
/* ----------------------------------------------------------------------
proc 0 reads from restart file, bcasts
------------------------------------------------------------------------- */
void PairZero::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(&cut[i][j],sizeof(double),1,fp);
}
MPI_Bcast(&cut[i][j],1,MPI_DOUBLE,0,world);
}
}
}
/* ----------------------------------------------------------------------
proc 0 writes to restart file
------------------------------------------------------------------------- */
void PairZero::write_restart_settings(FILE *fp)
{
fwrite(&cut_global,sizeof(double),1,fp);
fwrite(&coeffflag,sizeof(int),1,fp);
}
/* ----------------------------------------------------------------------
proc 0 reads from restart file, bcasts
------------------------------------------------------------------------- */
void PairZero::read_restart_settings(FILE *fp)
{
int me = comm->me;
if (me == 0) {
fread(&cut_global,sizeof(double),1,fp);
fread(&coeffflag,sizeof(int),1,fp);
}
MPI_Bcast(&cut_global,1,MPI_DOUBLE,0,world);
MPI_Bcast(&coeffflag,1,MPI_INT,0,world);
}
/* ----------------------------------------------------------------------
proc 0 writes to data file
------------------------------------------------------------------------- */
void PairZero::write_data(FILE *fp)
{
for (int i = 1; i <= atom->ntypes; i++)
fprintf(fp,"%d\n",i);
}
/* ----------------------------------------------------------------------
proc 0 writes all pairs to data file
------------------------------------------------------------------------- */
void PairZero::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\n",i,j,cut[i][j]);
}
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