Commit 57f337c9 authored by sjplimp's avatar sjplimp
Browse files 

git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@831 f3b2605a-c512-4ea7-a41b-209d697bcdaa
parent a21d4e48

src/fix_nve_limit.cpp

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/* ----------------------------------------------------------------------

   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator

   http://lammps.sandia.gov, 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.

------------------------------------------------------------------------- */



#include "math.h"

#include "stdio.h"

#include "stdlib.h"

#include "string.h"

#include "fix_nve_limit.h"

#include "atom.h"

#include "force.h"

#include "update.h"

#include "respa.h"

#include "error.h"



using namespace LAMMPS_NS;



/* ---------------------------------------------------------------------- */



FixNVELimit::FixNVELimit(LAMMPS *lmp, int narg, char **arg) :

  Fix(lmp, narg, arg)

{

  if (narg != 4) error->all("Illegal fix nve/limit command");



  xlimit = atof(arg[3]);

}



/* ---------------------------------------------------------------------- */



int FixNVELimit::setmask()

{

  int mask = 0;

  mask |= INITIAL_INTEGRATE;

  mask |= FINAL_INTEGRATE;

  mask |= INITIAL_INTEGRATE_RESPA;

  mask |= FINAL_INTEGRATE_RESPA;

  return mask;

}



/* ---------------------------------------------------------------------- */



void FixNVELimit::init()

{

  dtv = update->dt;

  dtf = 0.5 * update->dt * force->ftm2v;

  vlimitsq = (xlimit/dtv) * (xlimit/dtv);



  if (strcmp(update->integrate_style,"respa") == 0)

    step_respa = ((Respa *) update->integrate)->step;

}



/* ----------------------------------------------------------------------

   allow for both per-type and per-atom mass

------------------------------------------------------------------------- */



void FixNVELimit::initial_integrate()

{

  double dtfm,vsq,scale;



  double **x = atom->x;

  double **v = atom->v;

  double **f = atom->f;

  double *mass = atom->mass;

  double *rmass = atom->rmass;

  int *type = atom->type;

  int *mask = atom->mask;

  int nlocal = atom->nlocal;



  if (mass) {

    for (int i = 0; i < nlocal; i++) {

      if (mask[i] & groupbit) {

	dtfm = dtf / mass[type[i]];

	v[i][0] += dtfm * f[i][0];

	v[i][1] += dtfm * f[i][1];

	v[i][2] += dtfm * f[i][2];



	vsq = v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2];

	if (vsq > vlimitsq) {

	  scale = sqrt(vlimitsq/vsq);

	  v[i][0] *= scale;

	  v[i][1] *= scale;

	  v[i][2] *= scale;

	}



	x[i][0] += dtv * v[i][0];

	x[i][1] += dtv * v[i][1];

	x[i][2] += dtv * v[i][2];

      }

    }



  } else {

    for (int i = 0; i < nlocal; i++) {

      if (mask[i] & groupbit) {

	dtfm = dtf / rmass[i];

	v[i][0] += dtfm * f[i][0];

	v[i][1] += dtfm * f[i][1];

	v[i][2] += dtfm * f[i][2];



	vsq = v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2];

	if (vsq > vlimitsq) {

	  scale = sqrt(vlimitsq/vsq);

	  v[i][0] *= scale;

	  v[i][1] *= scale;

	  v[i][2] *= scale;

	}



	x[i][0] += dtv * v[i][0];

	x[i][1] += dtv * v[i][1];

	x[i][2] += dtv * v[i][2];

      }

    }

  }

}



/* ---------------------------------------------------------------------- */



void FixNVELimit::final_integrate()

{

  double dtfm,vsq,scale;



  double **v = atom->v;

  double **f = atom->f;

  double *mass = atom->mass;

  double *rmass = atom->rmass;

  int *type = atom->type;

  int *mask = atom->mask;

  int nlocal = atom->nlocal;



  if (mass) {

    for (int i = 0; i < nlocal; i++) {

      if (mask[i] & groupbit) {

	dtfm = dtf / mass[type[i]];

	v[i][0] += dtfm * f[i][0];

	v[i][1] += dtfm * f[i][1];

	v[i][2] += dtfm * f[i][2];



	vsq = v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2];

	if (vsq > vlimitsq) {

	  scale = sqrt(vlimitsq/vsq);

	  v[i][0] *= scale;

	  v[i][1] *= scale;

	  v[i][2] *= scale;

	}

      }

    }



  } else {

    for (int i = 0; i < nlocal; i++) {

      if (mask[i] & groupbit) {

	dtfm = dtf / rmass[i];

	v[i][0] += dtfm * f[i][0];

	v[i][1] += dtfm * f[i][1];

	v[i][2] += dtfm * f[i][2];



	vsq = v[i][0]*v[i][0] + v[i][1]*v[i][1] + v[i][2]*v[i][2];

	if (vsq > vlimitsq) {

	  scale = sqrt(vlimitsq/vsq);

	  v[i][0] *= scale;

	  v[i][1] *= scale;

	  v[i][2] *= scale;

	}

      }

    }

  }

}



/* ---------------------------------------------------------------------- */



void FixNVELimit::initial_integrate_respa(int ilevel, int flag)

{

  if (flag) return;             // only used by NPT,NPH



  dtv = step_respa[ilevel];

  dtf = 0.5 * step_respa[ilevel] * force->ftm2v;



  if (ilevel == 0) initial_integrate();

  else final_integrate();

}



/* ---------------------------------------------------------------------- */



void FixNVELimit::final_integrate_respa(int ilevel)

{

  dtf = 0.5 * step_respa[ilevel] * force->ftm2v;

  final_integrate();

}

src/fix_nve_limit.h

0 → 100644
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Original line number Diff line number Diff line 
/* ----------------------------------------------------------------------

   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator

   http://lammps.sandia.gov, 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.

------------------------------------------------------------------------- */



#ifndef FIX_NVE_LIMIT_H

#define FIX_NVE_LIMIT_H



#include "fix.h"



namespace LAMMPS_NS {



class FixNVELimit : public Fix {

 public:

  FixNVELimit(class LAMMPS *, int, char **);

  int setmask();

  void init();

  void initial_integrate();

  void final_integrate();

  void initial_integrate_respa(int, int);

  void final_integrate_respa(int);



 private:

  double dtv,dtf;

  double *step_respa;

  int mass_require;

  double xlimit,vlimitsq;

};



}



#endif

src/style.h

+7 −1
Original line number Diff line number Diff line
@@ -157,7 +157,9 @@ DumpStyle(xyz,DumpXYZ) 
#include "fix_momentum.h"

#include "fix_nph.h"

#include "fix_npt.h"

  //#include "fix_npt_pr.h"

#include "fix_nve.h"

#include "fix_nve_limit.h"

#include "fix_nve_noforce.h"

#include "fix_nvt.h"

#include "fix_nvt_sllod.h"
@@ -204,9 +206,11 @@ FixStyle(MINIMIZE,FixMinimize) 
FixStyle(momentum,FixMomentum)

FixStyle(msd,FixMSD)

FixStyle(nph,FixNPH)

  //FixStyle(npt/pr,FixNPTpr)

FixStyle(npt,FixNPT)

FixStyle(nve,FixNVE)

FixStyle(nve,FixNVENoforce)

FixStyle(nve/limit,FixNVELimit)

FixStyle(nve/noforce,FixNVENoforce)

FixStyle(nvt,FixNVT)

FixStyle(nvt/sllod,FixNVTSlodd)

FixStyle(orient/fcc,FixOrientFCC)
@@ -329,6 +333,8 @@ RegionStyle(union,RegUnion) 
#include "style_poems.h"

#include "style_xtc.h"



//#include "style_extra.h"



// user add-ons



#include "style_user.h"

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