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delete_atoms.cpp
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Sun, Nov 10, 07:40

delete_atoms.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 "stdlib.h"
#include "string.h"
#include "delete_atoms.h"
#include "atom.h"
#include "atom_vec.h"
#include "comm.h"
#include "domain.h"
#include "force.h"
#include "group.h"
#include "region.h"
#include "neighbor.h"
#include "comm.h"
#include "force.h"
#include "error.h"
using namespace LAMMPS_NS;
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define MAX(a,b) ((a) > (b) ? (a) : (b))
/* ---------------------------------------------------------------------- */
DeleteAtoms::DeleteAtoms(LAMMPS *lmp) : Pointers(lmp) {}
/* ---------------------------------------------------------------------- */
void DeleteAtoms::command(int narg, char **arg)
{
if (domain->box_exist == 0)
error->all("Delete_atoms command before simulation box is defined");
if (narg < 1) error->all("Illegal delete_atoms command");
// store state before delete
if (atom->tag_enable == 0)
error->all("Cannot use delete_atoms unless atoms have IDs");
int natoms_previous = static_cast<int> (atom->natoms);
// allocate and initialize deletion list
int nlocal = atom->nlocal;
int *list = new int[nlocal];
for (int i = 0; i < nlocal; i++) list[i] = 0;
// delete the atoms
if (strcmp(arg[0],"group") == 0) delete_group(narg,arg,list);
else if (strcmp(arg[0],"region") == 0) delete_region(narg,arg,list);
else if (strcmp(arg[0],"overlap") == 0) delete_overlap(narg,arg,list);
else error->all("Illegal delete_atoms command");
// delete local atoms in list
// reset nlocal
AtomVec *avec = atom->avec;
int i = 0;
while (i < nlocal) {
if (list[i]) {
avec->copy(nlocal-1,i);
list[i] = list[nlocal-1];
nlocal--;
} else i++;
}
atom->nlocal = nlocal;
delete [] list;
// if non-molecular system, reset atom tags to be contiguous
// set all atom IDs to 0, call tag_extend()
if (atom->molecular == 0) {
int *tag = atom->tag;
int nlocal = atom->nlocal;
for (i = 0; i < nlocal; i++) tag[i] = 0;
atom->tag_extend();
}
// reset atom->natoms
// reset atom->map if it exists
// set nghost to 0 so old ghosts of deleted atoms won't be mapped
double rlocal = atom->nlocal;
MPI_Allreduce(&rlocal,&atom->natoms,1,MPI_DOUBLE,MPI_SUM,world);
if (atom->map_style) {
atom->nghost = 0;
atom->map_init();
atom->map_set();
}
// print before and after atom count
int ndelete = static_cast<int> (natoms_previous - atom->natoms);
if (comm->me == 0) {
if (screen) fprintf(screen,"Deleted %d atoms, new total = %.15g\n",
ndelete,atom->natoms);
if (logfile) fprintf(logfile,"Deleted %d atoms, new total = %.15g\n",
ndelete,atom->natoms);
}
}
/* ----------------------------------------------------------------------
delete all atoms in group
group will still exist
------------------------------------------------------------------------- */
void DeleteAtoms::delete_group(int narg, char **arg, int *list)
{
if (narg != 2) error->all("Illegal delete_atoms command");
int igroup = group->find(arg[1]);
if (igroup == -1) error->all("Could not find delete_atoms group ID");
int *mask = atom->mask;
int nlocal = atom->nlocal;
int groupbit = group->bitmask[igroup];
for (int i = 0; i < nlocal; i++)
if (mask[i] & groupbit) list[i] = 1;
}
/* ----------------------------------------------------------------------
delete all atoms in region
------------------------------------------------------------------------- */
void DeleteAtoms::delete_region(int narg, char **arg, int *list)
{
if (narg != 2) error->all("Illegal delete_atoms command");
int iregion;
for (iregion = 0; iregion < domain->nregion; iregion++)
if (strcmp(arg[1],domain->regions[iregion]->id) == 0) break;
if (iregion == domain->nregion)
error->all("Could not find delete_atoms region ID");
double **x = atom->x;
int nlocal = atom->nlocal;
for (int i = 0; i < nlocal; i++)
if (domain->regions[iregion]->match(x[i][0],x[i][1],x[i][2])) list[i] = 1;
}
/* ----------------------------------------------------------------------
delete atoms so there are no pairs within cutoff
which atoms are deleted depends on ordering of atoms within proc
deletions can vary with processor count
no guarantee that minimium number of atoms will be deleted
------------------------------------------------------------------------- */
void DeleteAtoms::delete_overlap(int narg, char **arg, int *list)
{
if (narg < 2) error->all("Illegal delete_atoms command");
// read args including optional type info
double cut = atof(arg[1]);
double cutsq = cut*cut;
int typeflag,type1,type2;
if (narg == 2) typeflag = 0;
else if (narg == 3) {
typeflag = 1;
type1 = atoi(arg[2]);
} else if (narg == 4) {
typeflag = 2;
type1 = atoi(arg[2]);
type2 = atoi(arg[3]);
} else error->all("Illegal delete_atoms command");
// init entire system since comm->borders and neighbor->build is done
// comm::init needs neighbor::init needs pair::init needs kspace::init, etc
// set half_command since will require half neigh list even if
// neighbor would otherwise not create one, then unset it
if (comm->me == 0 && screen)
fprintf(screen,"System init for delete_atoms ...\n");
neighbor->half_command = 1;
lmp->init();
neighbor->half_command = 0;
// setup domain, communication and neighboring
// acquire ghosts
domain->pbc();
domain->reset_box();
comm->setup();
if (neighbor->style) neighbor->setup_bins();
comm->exchange();
comm->borders();
// call to build() forces memory allocation for neighbor lists
// build half list explicitly if build() doesn't do it
neighbor->build();
if (!neighbor->half_every) neighbor->build_half();
// error check on cutoff
if (cut > neighbor->cutneigh)
error->all("Delete_atoms cutoff > neighbor cutoff");
// create an atom map if one doesn't exist already
int mapflag = 0;
if (atom->map_style == 0) {
mapflag = 1;
atom->map_style = 1;
atom->map_init();
atom->map_set();
}
// double loop over owned atoms and their neighbors
// at end of loop, there are no more overlaps
// criteria for i,j to undergo a deletion event:
// weighting factor != 0.0 for this pair
// could be 0 and still be in neigh list for long-range Coulombics
// local copy of j (map[tag[j]]) has not already been deleted
// distance between i,j is less than cutoff
// i,j are of valid types
// if all criteria met, delete i and skip to next i in outer loop
// unless j is ghost and newton_pair off and tag[j] < tag[i]
// then rely on other proc to delete
int *tag = atom->tag;
int *type = atom->type;
double **x = atom->x;
int nlocal = atom->nlocal;
int nall = atom->nlocal + atom->nghost;
double *special_coul = force->special_coul;
double *special_lj = force->special_lj;
int newton_pair = force->newton_pair;
int i,j,k,m,itype,jtype,numneigh;
double xtmp,ytmp,ztmp,delx,dely,delz,rsq;
int *neighs;
for (i = 0; i < nlocal; i++) {
xtmp = x[i][0];
ytmp = x[i][1];
ztmp = x[i][2];
itype = type[i];
neighs = neighbor->firstneigh[i];
numneigh = neighbor->numneigh[i];
for (k = 0; k < numneigh; k++) {
j = neighs[k];
if (j >= nall) {
if (special_coul[j/nall] == 0.0 && special_lj[j/nall] == 0.0) continue;
j %= nall;
}
if (j < nlocal) {
if (list[j]) continue;
} else {
m = atom->map(tag[j]);
if (m < nlocal && list[m]) continue;
}
delx = xtmp - x[j][0];
dely = ytmp - x[j][1];
delz = ztmp - x[j][2];
rsq = delx*delx + dely*dely + delz*delz;
if (rsq >= cutsq) continue;
if (typeflag) {
jtype = type[j];
if (typeflag == 1 && itype != type1 && jtype != type1) continue;
if (typeflag == 2 && !(itype == type1 && jtype == type2) &&
!(itype == type2 && jtype == type1)) continue;
}
if (j >= nlocal && newton_pair == 0 && tag[j] < tag[i]) continue;
list[i] = 1;
break;
}
}
// delete temporary atom map
if (mapflag) {
atom->map_delete();
atom->map_style = 0;
}
}

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