109 lines
3.2 KiB
C++
109 lines
3.2 KiB
C++
/* ----------------------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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https://www.lammps.org/, Sandia National Laboratories
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LAMMPS development team: developers@lammps.org
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Copyright (2003) Sandia Corporation. Under the terms of Contract
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DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
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certain rights in this software. This software is distributed under
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the GNU General Public License.
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See the README file in the top-level LAMMPS directory.
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------------------------------------------------------------------------- */
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#include "compute_erotate_sphere_atom.h"
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#include "atom.h"
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#include "comm.h"
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#include "error.h"
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#include "force.h"
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#include "memory.h"
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#include "modify.h"
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#include "update.h"
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using namespace LAMMPS_NS;
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static constexpr double INERTIA = 0.4; // moment of inertia prefactor for sphere
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/* ---------------------------------------------------------------------- */
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ComputeErotateSphereAtom::ComputeErotateSphereAtom(LAMMPS *lmp, int narg, char **arg) :
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Compute(lmp, narg, arg), erot(nullptr)
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{
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if (narg != 3) error->all(FLERR, "Illegal compute erotate/sphere//atom command");
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peratom_flag = 1;
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size_peratom_cols = 0;
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// error check
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if (!atom->omega_flag)
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error->all(FLERR, "Compute erotate/sphere/atom requires atom attribute omega");
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if (!atom->radius_flag)
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error->all(FLERR, "Compute erotate/sphere/atom requires atom attribute radius");
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nmax = 0;
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}
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/* ---------------------------------------------------------------------- */
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ComputeErotateSphereAtom::~ComputeErotateSphereAtom()
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{
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memory->destroy(erot);
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}
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/* ---------------------------------------------------------------------- */
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void ComputeErotateSphereAtom::init()
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{
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if (modify->get_compute_by_style(style).size() > 1)
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if (comm->me == 0) error->warning(FLERR, "More than one compute {}", style);
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pfactor = 0.5 * force->mvv2e * INERTIA;
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}
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/* ---------------------------------------------------------------------- */
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void ComputeErotateSphereAtom::compute_peratom()
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{
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invoked_peratom = update->ntimestep;
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// grow erot array if necessary
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if (atom->nmax > nmax) {
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memory->destroy(erot);
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nmax = atom->nmax;
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memory->create(erot, nmax, "erotate/sphere/atom:erot");
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vector_atom = erot;
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}
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// compute rotational kinetic energy for each atom in group
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// point particles will have erot = 0.0, due to radius = 0.0
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double **omega = atom->omega;
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double *radius = atom->radius;
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double *rmass = atom->rmass;
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int *mask = atom->mask;
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int nlocal = atom->nlocal;
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for (int i = 0; i < nlocal; i++) {
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if (mask[i] & groupbit) {
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erot[i] =
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(omega[i][0] * omega[i][0] + omega[i][1] * omega[i][1] + omega[i][2] * omega[i][2]) *
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radius[i] * radius[i] * rmass[i];
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erot[i] *= pfactor;
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} else
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erot[i] = 0.0;
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}
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}
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/* ----------------------------------------------------------------------
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memory usage of local atom-based array
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------------------------------------------------------------------------- */
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double ComputeErotateSphereAtom::memory_usage()
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{
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double bytes = (double) nmax * sizeof(double);
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return bytes;
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}
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