304 lines
8.6 KiB
C++
304 lines
8.6 KiB
C++
/* ----------------------------------------------------------------------
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LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
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http://lammps.sandia.gov, 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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#include <math.h>
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#include <stdio.h>
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#include <string.h>
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#include "fix_nve_sph_limit.h"
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#include "atom.h"
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#include "force.h"
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#include "update.h"
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#include "respa.h"
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#include "error.h"
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using namespace LAMMPS_NS;
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using namespace FixConst;
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/* ---------------------------------------------------------------------- */
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FixNVESphLimit::FixNVESphLimit(LAMMPS *lmp, int narg, char **arg) :
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Fix(lmp, narg, arg),
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dtv(0.),
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dtf(0.),
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step_respa(NULL),
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mass_require(false),
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ncount(0),
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xlimit(0.),
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vlimitsq(0.)
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{
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if (narg != 5) error->all(FLERR,"Illegal fix nve/sph/limit command");
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time_integrate = 1;
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scalar_flag = 1;
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global_freq = 1;
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extscalar = 1;
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if ((atom->e_flag != 1) || (atom->rho_flag != 1))
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error->all(FLERR,
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"fix sph command requires atom_style with both energy and density");
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if (strcmp(arg[3],"absolute") == 0)
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xlimit = force->numeric(FLERR,arg[4]);
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else
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error->fix_error(FLERR,this,"expecting keyword 'absolute'");
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}
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/* ---------------------------------------------------------------------- */
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int FixNVESphLimit::setmask()
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{
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int mask = 0;
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mask |= INITIAL_INTEGRATE;
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mask |= FINAL_INTEGRATE;
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mask |= INITIAL_INTEGRATE_RESPA;
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mask |= FINAL_INTEGRATE_RESPA;
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return mask;
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}
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/* ---------------------------------------------------------------------- */
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void FixNVESphLimit::init()
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{
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dtv = update->dt;
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dtf = 0.5 * update->dt * force->ftm2v;
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vlimitsq = (xlimit/dtv) * (xlimit/dtv);
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ncount = 0;
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if (strstr(update->integrate_style,"respa"))
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step_respa = ((Respa *) update->integrate)->step;
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}
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/* ----------------------------------------------------------------------
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allow for both per-type and per-atom mass
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------------------------------------------------------------------------- */
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void FixNVESphLimit::initial_integrate(int vflag)
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{
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double dtfm;
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// update v and x of atoms in group
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double **x = atom->x;
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double **v = atom->v;
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double **f = atom->f;
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double *rmass = atom->rmass;
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double *mass = atom->mass;
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int *type = atom->type;
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int *mask = atom->mask;
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int nlocal = atom->nlocal;
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double **vest = atom->vest;
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double *rho = atom->rho;
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double *drho = atom->drho;
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double *e = atom->e;
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double *de = atom->de;
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if (igroup == atom->firstgroup) nlocal = atom->nfirst;
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if (rmass) {
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for (int i = 0; i < nlocal; i++)
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if (mask[i] & groupbit) {
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dtfm = dtf / rmass[i];
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// same like src/USER-SPH/fix_meso !!
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e[i] += dtf * de[i]; // half-step update of particle internal energy
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//rho[i] += dtf * drho[i]; // ... and density
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rho[i] += 2.0 * dtf * drho[i]; // ... and density by full step
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// euler integration for velocity (estimation for force calculatoin)
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vest[i][0] = v[i][0] + 2.0 * dtfm * f[i][0];
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vest[i][1] = v[i][1] + 2.0 * dtfm * f[i][1];
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vest[i][2] = v[i][2] + 2.0 * dtfm * f[i][2];
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// half step
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v[i][0] += dtfm * f[i][0];
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v[i][1] += dtfm * f[i][1];
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v[i][2] += dtfm * f[i][2];
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// check half-step and estimated velocity (only if half step exceeds the limit)
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const double vsq = v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2];
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if (vsq > vlimitsq) {
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ncount++;
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const double scale = sqrt(vlimitsq/vsq);
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v[i][0] *= scale;
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v[i][1] *= scale;
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v[i][2] *= scale;
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const double vsqEst = vest[i][0]*vest[i][0] + vest[i][1]*vest[i][1] + vest[i][2]*vest[i][2];
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if (vsqEst > vlimitsq) {
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const double scaleEst = sqrt(vlimitsq/vsqEst);
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vest[i][0] *= scaleEst;
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vest[i][1] *= scaleEst;
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vest[i][2] *= scaleEst;
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}
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}
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x[i][0] += dtv * v[i][0];
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x[i][1] += dtv * v[i][1];
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x[i][2] += dtv * v[i][2];
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}
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} else {
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for (int i = 0; i < nlocal; i++)
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if (mask[i] & groupbit) {
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dtfm = dtf / mass[type[i]];
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e[i] += dtf * de[i]; // half-step update of particle internal energy
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//rho[i] += dtf * drho[i]; // ... and density
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rho[i] += 2.0 * dtf * drho[i]; // ... and density
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// euler integration for velocity
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vest[i][0] = v[i][0] + 2.0 * dtfm * f[i][0];
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vest[i][1] = v[i][1] + 2.0 * dtfm * f[i][1];
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vest[i][2] = v[i][2] + 2.0 * dtfm * f[i][2];
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v[i][0] += dtfm * f[i][0];
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v[i][1] += dtfm * f[i][1];
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v[i][2] += dtfm * f[i][2];
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// check half-step and estimated velocity (only if half step exceeds the limit)
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const double vsq = v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2];
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if (vsq > vlimitsq) {
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ncount++;
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const double scale = sqrt(vlimitsq/vsq);
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v[i][0] *= scale;
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v[i][1] *= scale;
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v[i][2] *= scale;
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const double vsqEst = vest[i][0]*vest[i][0] + vest[i][1]*vest[i][1] + vest[i][2]*vest[i][2];
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if (vsqEst > vlimitsq) {
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const double scaleEst = sqrt(vlimitsq/vsqEst);
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vest[i][0] *= scaleEst;
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vest[i][1] *= scaleEst;
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vest[i][2] *= scaleEst;
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}
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}
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x[i][0] += dtv * v[i][0];
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x[i][1] += dtv * v[i][1];
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x[i][2] += dtv * v[i][2];
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}
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}
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}
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/* ---------------------------------------------------------------------- */
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void FixNVESphLimit::final_integrate()
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{
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double dtfm;
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// update v of atoms in group
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double **v = atom->v;
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double **f = atom->f;
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double *rmass = atom->rmass;
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double *mass = atom->mass;
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int *type = atom->type;
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int *mask = atom->mask;
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int nlocal = atom->nlocal;
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//double *rho = atom->rho; //NP modified R.B.
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//const double *drho = atom->drho;
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double *e = atom->e;
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double *de = atom->de;
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if (igroup == atom->firstgroup) nlocal = atom->nfirst;
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if (rmass) {
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for (int i = 0; i < nlocal; i++)
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if (mask[i] & groupbit) {
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dtfm = dtf / rmass[i];
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v[i][0] += dtfm * f[i][0];
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v[i][1] += dtfm * f[i][1];
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v[i][2] += dtfm * f[i][2];
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const double vsq = v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2];
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if (vsq > vlimitsq) {
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ncount++;
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const double scale = sqrt(vlimitsq/vsq);
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v[i][0] *= scale;
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v[i][1] *= scale;
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v[i][2] *= scale;
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}
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e[i] += dtf * de[i]; // half-step update of particle internal energy
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//rho[i] += dtf * drho[i]; // ... and density
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}
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} else {
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for (int i = 0; i < nlocal; i++)
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if (mask[i] & groupbit) {
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dtfm = dtf / mass[type[i]];
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v[i][0] += dtfm * f[i][0];
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v[i][1] += dtfm * f[i][1];
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v[i][2] += dtfm * f[i][2];
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const double vsq = v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2];
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if (vsq > vlimitsq) {
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ncount++;
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const double scale = sqrt(vlimitsq/vsq);
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v[i][0] *= scale;
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v[i][1] *= scale;
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v[i][2] *= scale;
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}
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e[i] += dtf * de[i]; // half-step update of particle internal energy
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//rho[i] += dtf * drho[i]; // ... and density
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}
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}
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}
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/* ---------------------------------------------------------------------- */
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void FixNVESphLimit::initial_integrate_respa(int vflag, int ilevel, int iloop)
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{
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dtv = step_respa[ilevel];
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dtf = 0.5 * step_respa[ilevel] * force->ftm2v;
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// innermost level - NVE update of v and x
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// all other levels - NVE update of v
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if (ilevel == 0) initial_integrate(vflag);
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else final_integrate();
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}
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/* ---------------------------------------------------------------------- */
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void FixNVESphLimit::final_integrate_respa(int ilevel, int iloop)
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{
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dtf = 0.5 * step_respa[ilevel] * force->ftm2v;
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final_integrate();
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}
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/* ---------------------------------------------------------------------- */
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void FixNVESphLimit::reset_dt()
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{
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dtv = update->dt;
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dtf = 0.5 * update->dt * force->ftm2v;
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vlimitsq = (xlimit/dtv) * (xlimit/dtv);
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}
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/* ----------------------------------------------------------------------
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energy of indenter interaction
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------------------------------------------------------------------------- */
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double FixNVESphLimit::compute_scalar()
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{
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double one = ncount;
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double all;
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MPI_Allreduce(&one,&all,1,MPI_DOUBLE,MPI_SUM,world);
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return all;
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}
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