155 lines
4.6 KiB
C++
155 lines
4.6 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 "omp_compat.h"
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#include "angle_dipole_omp.h"
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#include <cmath>
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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 "neighbor.h"
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#include "suffix.h"
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using namespace LAMMPS_NS;
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#define SMALL 0.001
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/* ---------------------------------------------------------------------- */
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AngleDipoleOMP::AngleDipoleOMP(class LAMMPS *lmp)
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: AngleDipole(lmp), ThrOMP(lmp,THR_ANGLE)
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{
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suffix_flag |= Suffix::OMP;
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}
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/* ---------------------------------------------------------------------- */
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void AngleDipoleOMP::compute(int eflag, int vflag)
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{
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ev_init(eflag,vflag);
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if (!force->newton_bond)
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error->all(FLERR,"'newton' flag for bonded interactions must be 'on'");
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const int nall = atom->nlocal + atom->nghost;
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const int nthreads = comm->nthreads;
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const int inum = neighbor->nanglelist;
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#if defined(_OPENMP)
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#pragma omp parallel LMP_DEFAULT_NONE LMP_SHARED(eflag,vflag)
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#endif
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{
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int ifrom, ito, tid;
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loop_setup_thr(ifrom, ito, tid, inum, nthreads);
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ThrData *thr = fix->get_thr(tid);
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thr->timer(Timer::START);
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ev_setup_thr(eflag, vflag, nall, eatom, vatom, cvatom, thr);
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if (inum > 0) {
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if (evflag)
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eval<1>(ifrom, ito, thr);
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else
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eval<0>(ifrom, ito, thr);
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}
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thr->timer(Timer::BOND);
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reduce_thr(this, eflag, vflag, thr);
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} // end of omp parallel region
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}
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template <int EVFLAG>
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void AngleDipoleOMP::eval(int nfrom, int nto, ThrData * const thr)
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{
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int iRef,iDip,iDummy,n,type;
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double delx,dely,delz;
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double eangle,tangle,fi[3],fj[3];
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double r,cosGamma,deltaGamma,kdg,rmu;
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double delTx, delTy, delTz;
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double fx, fy, fz, fmod, fmod_sqrtff;
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const double * const * const x = atom->x; // position vector
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const double * const * const mu = atom->mu; // point-dipole components and moment magnitude
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double * const * const f = thr->get_f();
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double * const * const torque = thr->get_torque();
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const int * const * const anglelist = neighbor->anglelist;
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const int nlocal = atom->nlocal;
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eangle = 0.0;
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for (n = nfrom; n < nto; n++) {
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iDip = anglelist[n][0]; // dipole whose orientation is to be restrained
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iRef = anglelist[n][1]; // reference atom toward which dipole will point
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iDummy = anglelist[n][2]; // dummy atom - irrelevant to the interaction
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type = anglelist[n][3];
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delx = x[iRef][0] - x[iDip][0];
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dely = x[iRef][1] - x[iDip][1];
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delz = x[iRef][2] - x[iDip][2];
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r = sqrt(delx*delx + dely*dely + delz*delz);
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rmu = r * mu[iDip][3];
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cosGamma = (mu[iDip][0]*delx+mu[iDip][1]*dely+mu[iDip][2]*delz) / rmu;
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deltaGamma = cosGamma - cos(gamma0[type]);
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kdg = k[type] * deltaGamma;
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if (EVFLAG) eangle = kdg * deltaGamma; // energy
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tangle = 2.0 * kdg / rmu;
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delTx = tangle * (dely*mu[iDip][2] - delz*mu[iDip][1]);
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delTy = tangle * (delz*mu[iDip][0] - delx*mu[iDip][2]);
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delTz = tangle * (delx*mu[iDip][1] - dely*mu[iDip][0]);
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torque[iDip][0] += delTx;
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torque[iDip][1] += delTy;
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torque[iDip][2] += delTz;
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// Force couple that counterbalances dipolar torque
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fx = dely*delTz - delz*delTy; // direction (fi): - r x (-T)
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fy = delz*delTx - delx*delTz;
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fz = delx*delTy - dely*delTx;
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fmod = sqrt(delTx*delTx + delTy*delTy + delTz*delTz) / r; // magnitude
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fmod_sqrtff = fmod / sqrt(fx*fx + fy*fy + fz*fz);
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fi[0] = fx * fmod_sqrtff;
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fi[1] = fy * fmod_sqrtff;
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fi[2] = fz * fmod_sqrtff;
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fj[0] = -fi[0];
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fj[1] = -fi[1];
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fj[2] = -fi[2];
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f[iDip][0] += fj[0];
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f[iDip][1] += fj[1];
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f[iDip][2] += fj[2];
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f[iRef][0] += fi[0];
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f[iRef][1] += fi[1];
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f[iRef][2] += fi[2];
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if (EVFLAG) // virial = rij.fi = 0 (fj = -fi & fk = 0)
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ev_tally_thr(this,iRef,iDip,iDummy,nlocal,/* NEWTON_BOND */ 1,
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eangle,fi,fj,0.0,0.0,0.0,0.0,0.0,0.0,thr);
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}
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}
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