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verlet.cpp
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Sun, Jun 2, 15:34

verlet.cpp

/* ----------------------------------------------------------------------
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 "string.h"
#include "verlet.h"
#include "neighbor.h"
#include "domain.h"
#include "comm.h"
#include "atom.h"
#include "force.h"
#include "pair.h"
#include "bond.h"
#include "angle.h"
#include "dihedral.h"
#include "improper.h"
#include "kspace.h"
#include "output.h"
#include "update.h"
#include "modify.h"
#include "compute.h"
#include "fix.h"
#include "timer.h"
#include "memory.h"
#include "error.h"
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
Verlet::Verlet(LAMMPS *lmp, int narg, char **arg) :
Integrate(lmp, narg, arg) {}
/* ----------------------------------------------------------------------
initialization before run
------------------------------------------------------------------------- */
void Verlet::init()
{
// warn if no fixes
if (modify->nfix == 0 && comm->me == 0)
error->warning("No fixes defined, atoms won't move");
// virial_style:
// 1 if computed explicitly by pair->compute via sum over pair interactions
// 2 if computed implicitly by pair->virial_compute via sum over ghost atoms
if (force->newton_pair) virial_style = 2;
else virial_style = 1;
// setup lists of computes for global and per-atom PE and pressure
ev_setup();
// set flags for what arrays to clear in force_clear()
// need to clear torques if array exists
torqueflag = 0;
if (atom->torque_flag) torqueflag = 1;
// orthogonal vs triclinic simulation box
triclinic = domain->triclinic;
}
/* ----------------------------------------------------------------------
setup before run
------------------------------------------------------------------------- */
void Verlet::setup()
{
if (comm->me == 0 && screen) fprintf(screen,"Setting up run ...\n");
// setup domain, communication and neighboring
// acquire ghosts
// build neighbor lists
if (triclinic) domain->x2lamda(atom->nlocal);
domain->pbc();
domain->reset_box();
comm->setup();
if (neighbor->style) neighbor->setup_bins();
comm->exchange();
comm->borders();
if (triclinic) domain->lamda2x(atom->nlocal+atom->nghost);
neighbor->build();
neighbor->ncalls = 0;
// compute all forces
ev_set(update->ntimestep);
force_clear();
if (force->pair) force->pair->compute(eflag,vflag);
if (atom->molecular) {
if (force->bond) force->bond->compute(eflag,vflag);
if (force->angle) force->angle->compute(eflag,vflag);
if (force->dihedral) force->dihedral->compute(eflag,vflag);
if (force->improper) force->improper->compute(eflag,vflag);
}
if (force->kspace) {
force->kspace->setup();
force->kspace->compute(eflag,vflag);
}
if (force->newton) comm->reverse_communicate();
modify->setup(vflag);
output->setup(1);
}
/* ----------------------------------------------------------------------
setup without output
flag = 0 = just force calculation
flag = 1 = reneighbor and force calculation
------------------------------------------------------------------------- */
void Verlet::setup_minimal(int flag)
{
// setup domain, communication and neighboring
// acquire ghosts
// build neighbor lists
if (flag) {
if (triclinic) domain->x2lamda(atom->nlocal);
domain->pbc();
domain->reset_box();
comm->setup();
if (neighbor->style) neighbor->setup_bins();
comm->exchange();
comm->borders();
if (triclinic) domain->lamda2x(atom->nlocal+atom->nghost);
neighbor->build();
neighbor->ncalls = 0;
}
// compute all forces
ev_set(update->ntimestep);
force_clear();
if (force->pair) force->pair->compute(eflag,vflag);
if (atom->molecular) {
if (force->bond) force->bond->compute(eflag,vflag);
if (force->angle) force->angle->compute(eflag,vflag);
if (force->dihedral) force->dihedral->compute(eflag,vflag);
if (force->improper) force->improper->compute(eflag,vflag);
}
if (force->kspace) {
force->kspace->setup();
force->kspace->compute(eflag,vflag);
}
if (force->newton) comm->reverse_communicate();
modify->setup(vflag);
}
/* ----------------------------------------------------------------------
run for N steps
------------------------------------------------------------------------- */
void Verlet::run(int n)
{
int nflag,ntimestep;
int n_post_integrate = modify->n_post_integrate;
int n_pre_exchange = modify->n_pre_exchange;
int n_pre_neighbor = modify->n_pre_neighbor;
int n_pre_force = modify->n_pre_force;
int n_post_force = modify->n_post_force;
int n_end_of_step = modify->n_end_of_step;
for (int i = 0; i < n; i++) {
ntimestep = ++update->ntimestep;
ev_set(ntimestep);
// initial time integration
modify->initial_integrate(vflag);
if (n_post_integrate) modify->post_integrate();
// regular communication vs neighbor list rebuild
nflag = neighbor->decide();
if (nflag == 0) {
timer->stamp();
comm->communicate();
timer->stamp(TIME_COMM);
} else {
if (n_pre_exchange) modify->pre_exchange();
if (triclinic) domain->x2lamda(atom->nlocal);
domain->pbc();
if (domain->box_change) {
domain->reset_box();
comm->setup();
if (neighbor->style) neighbor->setup_bins();
}
timer->stamp();
comm->exchange();
comm->borders();
if (triclinic) domain->lamda2x(atom->nlocal+atom->nghost);
timer->stamp(TIME_COMM);
if (n_pre_neighbor) modify->pre_neighbor();
neighbor->build();
timer->stamp(TIME_NEIGHBOR);
}
// force computations
force_clear();
if (n_pre_force) modify->pre_force(vflag);
timer->stamp();
if (force->pair) {
force->pair->compute(eflag,vflag);
timer->stamp(TIME_PAIR);
}
if (atom->molecular) {
if (force->bond) force->bond->compute(eflag,vflag);
if (force->angle) force->angle->compute(eflag,vflag);
if (force->dihedral) force->dihedral->compute(eflag,vflag);
if (force->improper) force->improper->compute(eflag,vflag);
timer->stamp(TIME_BOND);
}
if (force->kspace) {
force->kspace->compute(eflag,vflag);
timer->stamp(TIME_KSPACE);
}
// reverse communication of forces
if (force->newton) {
comm->reverse_communicate();
timer->stamp(TIME_COMM);
}
// force modifications, final time integration, diagnostics
if (n_post_force) modify->post_force(vflag);
modify->final_integrate();
if (n_end_of_step) modify->end_of_step();
// all output
if (ntimestep == output->next) {
timer->stamp();
output->write(ntimestep);
timer->stamp(TIME_OUTPUT);
}
}
}
/* ----------------------------------------------------------------------
clear force on own & ghost atoms
setup and clear other arrays as needed
------------------------------------------------------------------------- */
void Verlet::force_clear()
{
int i;
// clear force on all particles
// if either newton flag is set, also include ghosts
if (neighbor->includegroup == 0) {
int nall;
if (force->newton) nall = atom->nlocal + atom->nghost;
else nall = atom->nlocal;
double **f = atom->f;
for (i = 0; i < nall; i++) {
f[i][0] = 0.0;
f[i][1] = 0.0;
f[i][2] = 0.0;
}
if (torqueflag) {
double **torque = atom->torque;
for (i = 0; i < nall; i++) {
torque[i][0] = 0.0;
torque[i][1] = 0.0;
torque[i][2] = 0.0;
}
}
// neighbor includegroup flag is set
// clear force only on initial nfirst particles
// if either newton flag is set, also include ghosts
} else {
int nall = atom->nfirst;
double **f = atom->f;
for (i = 0; i < nall; i++) {
f[i][0] = 0.0;
f[i][1] = 0.0;
f[i][2] = 0.0;
}
if (torqueflag) {
double **torque = atom->torque;
for (i = 0; i < nall; i++) {
torque[i][0] = 0.0;
torque[i][1] = 0.0;
torque[i][2] = 0.0;
}
}
if (force->newton) {
nall = atom->nlocal + atom->nghost;
for (i = atom->nlocal; i < nall; i++) {
f[i][0] = 0.0;
f[i][1] = 0.0;
f[i][2] = 0.0;
}
if (torqueflag) {
double **torque = atom->torque;
for (i = atom->nlocal; i < nall; i++) {
torque[i][0] = 0.0;
torque[i][1] = 0.0;
torque[i][2] = 0.0;
}
}
}
}
}

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