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lammps/src/compute_ke_atom.cpp
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compute_ke_atom.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 "string.h"
#include "compute_ke_atom.h"
#include "atom.h"
#include "modify.h"
#include "comm.h"
#include "force.h"
#include "memory.h"
#include "error.h"
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
ComputeKEAtom::ComputeKEAtom(LAMMPS *lmp, int narg, char **arg) :
Compute(lmp, narg, arg)
{
if (narg != 3) error->all("Illegal compute ke/atom command");
peratom_flag = 1;
size_peratom = 0;
nmax = 0;
ke = NULL;
}
/* ---------------------------------------------------------------------- */
ComputeKEAtom::~ComputeKEAtom()
{
memory->sfree(ke);
}
/* ---------------------------------------------------------------------- */
void ComputeKEAtom::init()
{
int count = 0;
for (int i = 0; i < modify->ncompute; i++)
if (strcmp(modify->compute[i]->style,"ke/atom") == 0) count++;
if (count > 1 && comm->me == 0)
error->warning("More than one compute ke/atom defined");
}
/* ---------------------------------------------------------------------- */
void ComputeKEAtom::compute_peratom()
{
// grow ke array if necessary
if (atom->nlocal > nmax) {
memory->sfree(ke);
nmax = atom->nmax;
ke = (double *) memory->smalloc(nmax*sizeof(double),"compute/ke/atom:ke");
scalar_atom = ke;
}
// compute kinetic energy for each atom in group
double mvv2e = force->mvv2e;
double **v = atom->v;
double *mass = atom->mass;
double *rmass = atom->rmass;
int *mask = atom->mask;
int *type = atom->type;
int nlocal = atom->nlocal;
if (mass)
for (int i = 0; i < nlocal; i++) {
if (mask[i] & groupbit) {
ke[i] = 0.5 * mvv2e * mass[type[i]] *
(v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2]);
}
}
else
for (int i = 0; i < nlocal; i++) {
if (mask[i] & groupbit) {
ke[i] = 0.5 * mvv2e * rmass[i] *
(v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2]);
}
}
}
/* ----------------------------------------------------------------------
memory usage of local atom-based array
------------------------------------------------------------------------- */
int ComputeKEAtom::memory_usage()
{
int bytes = nmax * sizeof(double);
return bytes;
}
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