Files
lammps/src/SPIN/atom_vec_spin.cpp

102 lines
3.4 KiB
C++

/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
https://www.lammps.org/, 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 authors: Julien Tranchida (SNL)
Aidan Thompson (SNL)
Please cite the related publication:
Tranchida, J., Plimpton, S. J., Thibaudeau, P., & Thompson, A. P. (2018).
Massively parallel symplectic algorithm for coupled magnetic spin dynamics
and molecular dynamics. Journal of Computational Physics.
------------------------------------------------------------------------- */
#include "atom_vec_spin.h"
#include "atom.h"
#include <cmath>
using namespace LAMMPS_NS;
/* ---------------------------------------------------------------------- */
AtomVecSpin::AtomVecSpin(LAMMPS *lmp) : AtomVec(lmp)
{
molecular = Atom::ATOMIC;
mass_type = PER_TYPE;
forceclearflag = 1;
atom->sp_flag = 1;
// strings with peratom variables to include in each AtomVec method
// strings cannot contain fields in corresponding AtomVec default strings
// order of fields in a string does not matter
// except: fields_data_atom & fields_data_vel must match data file
fields_grow = {"sp", "fm", "fm_long"};
fields_copy = {"sp"};
fields_comm = {"sp"};
fields_comm_vel = {"sp"};
fields_reverse = {"fm", "fm_long"};
fields_border = {"sp"};
fields_border_vel = {"sp"};
fields_exchange = {"sp"};
fields_restart = {"sp"};
fields_create = {"sp"};
fields_data_atom = {"id", "type", "x", "sp"};
fields_data_vel = {"id", "v"};
setup_fields();
}
/* ----------------------------------------------------------------------
set local copies of all grow ptrs used by this class, except defaults
needed in replicate when 2 atom classes exist and it calls pack_restart()
------------------------------------------------------------------------- */
void AtomVecSpin::grow_pointers()
{
sp = atom->sp;
fm = atom->fm;
fm_long = atom->fm_long;
}
/* ----------------------------------------------------------------------
clear extra forces starting at atom N
nbytes = # of bytes to clear for a per-atom vector
include f b/c this is invoked from within SPIN pair styles
------------------------------------------------------------------------- */
void AtomVecSpin::force_clear(int n, size_t nbytes)
{
memset(&fm[n][0], 0, 3 * nbytes);
memset(&fm_long[n][0], 0, 3 * nbytes);
}
/* ----------------------------------------------------------------------
modify what AtomVec::data_atom() just unpacked
or initialize other atom quantities
------------------------------------------------------------------------- */
void AtomVecSpin::data_atom_post(int ilocal)
{
double *sp_one = sp[ilocal];
double norm = 1.0 / sqrt(sp_one[0] * sp_one[0] + sp_one[1] * sp_one[1] + sp_one[2] * sp_one[2]);
sp_one[0] *= norm;
sp_one[1] *= norm;
sp_one[2] *= norm;
}