152 lines
4.8 KiB
C++
152 lines
4.8 KiB
C++
// clang-format off
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/* ----------------------------------------------------------------------
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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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Steve Plimpton, sjplimp@sandia.gov
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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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/* ----------------------------------------------------------------------
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Contributing author: Axel Kohlmeyer (Temple U)
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------------------------------------------------------------------------- */
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#include "fix_nh_sphere_omp.h"
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#include "atom.h"
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#include "compute.h"
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#include "error.h"
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#include "omp_compat.h"
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using namespace LAMMPS_NS;
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using namespace FixConst;
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enum{NOBIAS,BIAS};
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#define INERTIA 0.4 // moment of inertia prefactor for sphere
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typedef struct { double x,y,z; } dbl3_t;
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/* ---------------------------------------------------------------------- */
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FixNHSphereOMP::FixNHSphereOMP(LAMMPS *lmp, int narg, char **arg) :
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FixNHOMP(lmp, narg, arg)
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{
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if (!atom->sphere_flag)
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error->all(FLERR,"Fix nvt/nph/npt sphere requires atom style sphere");
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}
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/* ---------------------------------------------------------------------- */
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void FixNHSphereOMP::init()
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{
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// check that all particles are finite-size
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// no point particles allowed
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double *radius = atom->radius;
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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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if (radius[i] == 0.0)
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error->one(FLERR,"Fix nvt/npt/nph/sphere/omp require extended particles");
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FixNHOMP::init();
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}
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/* ----------------------------------------------------------------------
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perform half-step update of rotational and COM velocities
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-----------------------------------------------------------------------*/
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void FixNHSphereOMP::nve_v()
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{
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auto * _noalias const v = (dbl3_t *) atom->v[0];
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auto * _noalias const omega = (dbl3_t *) atom->omega[0];
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const auto * _noalias const f = (dbl3_t *) atom->f[0];
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const auto * _noalias const torque = (dbl3_t *) atom->torque[0];
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const double * _noalias const radius = atom->radius;
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const double * _noalias const rmass = atom->rmass;
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const int * _noalias const mask = atom->mask;
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// set timestep here since dt may have changed or come via rRESPA
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const double dtfrotate = dtf / INERTIA;
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const int nlocal = (igroup == atom->firstgroup) ? atom->nfirst : atom->nlocal;
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// standard nve_v velocity update. for efficiency the loop is
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// merged with FixNHOMP instead of calling it for the COM update.
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// update omega for all particles
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// d_omega/dt = torque / inertia
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// 4 cases depending on radius vs shape and rmass vs mass
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#if defined(_OPENMP)
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#pragma omp parallel for LMP_DEFAULT_NONE schedule(static)
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#endif
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for (int i = 0; i < nlocal; i++) {
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if (mask[i] & groupbit) {
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const double dtfm = dtf / rmass[i];
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v[i].x += dtfm*f[i].x;
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v[i].y += dtfm*f[i].y;
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v[i].z += dtfm*f[i].z;
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const double dtirotate = dtfrotate / (radius[i]*radius[i]*rmass[i]);
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omega[i].x += dtirotate*torque[i].x;
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omega[i].y += dtirotate*torque[i].y;
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omega[i].z += dtirotate*torque[i].z;
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}
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}
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}
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/* ----------------------------------------------------------------------
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perform half-step scaling of rotatonal velocities
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-----------------------------------------------------------------------*/
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void FixNHSphereOMP::nh_v_temp()
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{
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auto * _noalias const v = (dbl3_t *) atom->v[0];
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auto * _noalias const omega = (dbl3_t *) atom->omega[0];
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const int * _noalias const mask = atom->mask;
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const int nlocal = (igroup == atom->firstgroup) ? atom->nfirst : atom->nlocal;
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if (which == NOBIAS) {
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#if defined(_OPENMP)
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#pragma omp parallel for LMP_DEFAULT_NONE schedule(static)
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#endif
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for (int i = 0; i < nlocal; i++) {
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if (mask[i] & groupbit) {
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v[i].x *= factor_eta;
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v[i].y *= factor_eta;
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v[i].z *= factor_eta;
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omega[i].x *= factor_eta;
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omega[i].y *= factor_eta;
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omega[i].z *= factor_eta;
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}
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}
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} else if (which == BIAS) {
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#if defined(_OPENMP)
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#pragma omp parallel for LMP_DEFAULT_NONE schedule(static)
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#endif
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for (int i = 0; i < nlocal; i++) {
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double buf[3];
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if (mask[i] & groupbit) {
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temperature->remove_bias_thr(i,&v[i].x,buf);
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v[i].x *= factor_eta;
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v[i].y *= factor_eta;
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v[i].z *= factor_eta;
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temperature->restore_bias_thr(i,&v[i].x,buf);
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omega[i].x *= factor_eta;
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omega[i].y *= factor_eta;
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omega[i].z *= factor_eta;
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}
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}
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}
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}
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