import fix halt prototype code with corrections for soft exit

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

   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 <stdlib.h>

#include <string.h>

#include "fix_halt.h"

#include "update.h"

#include "force.h"

#include "input.h"

#include "modify.h"

#include "comm.h"

#include "timer.h"

#include "variable.h"

#include "error.h"

using namespace LAMMPS_NS;

using namespace FixConst;

enum{BONDMAX,VARIABLE};

enum{LT,LE,GT,GE,EQ,NEQ,XOR};

enum{SOFT,HARD};

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

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

  Fix(lmp, narg, arg), idvar(NULL)

{

  if (narg < 7) error->all(FLERR,"Illegal fix halt command");

  nevery = force->inumeric(FLERR,arg[3]);

  if (nevery <= 0) error->all(FLERR,"Illegal fix halt command");

  // comparison args

  idvar = NULL;

  if (strcmp(arg[4],"bondmax") == 0) attribute = BONDMAX;

  else if (strncmp(arg[4],"v_",2) == 0) {

    attribute = VARIABLE;

    int n = strlen(arg[4]);

    idvar = new char[n];

    strcpy(idvar,&arg[4][2]);

    ivar = input->variable->find(idvar);

    if (ivar < 0) error->all(FLERR,"Could not find fix halt variable name");

    if (input->variable->equalstyle(ivar) == 0)

      error->all(FLERR,"Fix halt variable is not equal-style variable");

  } else error->all(FLERR,"Invalid fix halt attribute");

  if (strcmp(arg[5],"<") == 0) operation = LT;

  else if (strcmp(arg[5],"<=") == 0) operation = LE;

  else if (strcmp(arg[5],">") == 0) operation = GT;

  else if (strcmp(arg[5],">=") == 0) operation = GE;

  else if (strcmp(arg[5],"==") == 0) operation = EQ;

  else if (strcmp(arg[5],"!=") == 0) operation = NEQ;

  else if (strcmp(arg[5],"|^") == 0) operation = XOR;

  else error->all(FLERR,"Invalid fix halt operator");

  value = force->numeric(FLERR,arg[6]);

  // parse optional args

  eflag = SOFT;

  int iarg = 7;

  while (iarg < narg) {

    if (strcmp(arg[iarg],"error") == 0) {

      if (iarg+2 > narg) error->all(FLERR,"Illegal fix halt command");

      if (strcmp(arg[iarg+1],"soft") == 0) eflag = SOFT;

      else if (strcmp(arg[iarg+1],"hard") == 0) eflag = HARD;

      else error->all(FLERR,"Illegal fix halt command");

      iarg += 2;

    } else error->all(FLERR,"Illegal fix halt command");

  }

  // add nfirst to all computes that store invocation times

  // since don't know a priori which are invoked via variables by this fix

  // once in end_of_step() can set timestep for ones actually invoked

  if (attribute == VARIABLE) {

    const bigint nfirst = (update->ntimestep/nevery)*nevery + nevery;

    modify->addstep_compute_all(nfirst);

  }

}

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

FixHalt::~FixHalt()

{

  delete [] idvar;

}

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

int FixHalt::setmask()

{

  int mask = 0;

  mask |= END_OF_STEP;

  return mask;

}

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

void FixHalt::init()

{

  // set ivar from current variable list

  ivar = input->variable->find(idvar);

  if (ivar < 0) error->all(FLERR,"Could not find fix halt variable name");

  if (input->variable->equalstyle(ivar) == 0)

    error->all(FLERR,"Fix halt variable is not equal-style variable");

}

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

void FixHalt::end_of_step()

{

  // make a copy of string to work on

  // substitute for $ variables (no printing)

  // append a newline and print final copy

  // variable evaluation may invoke computes so wrap with clear/add

  double attvalue;

  if (attribute == BONDMAX) attvalue = bondmax();

  else {

    modify->clearstep_compute();

    attvalue = input->variable->compute_equal(ivar);

    modify->addstep_compute(update->ntimestep + nevery);

  }

  // check if halt is triggered, else just return

  if (operation == LT) {

    if (attvalue >= value) return;

  } else if (operation == LE) {

    if (attvalue > value) return;

  } else if (operation == GT) {

    if (attvalue <= value) return;

  } else if (operation == GE) {

    if (attvalue < value) return;

  } else if (operation == EQ) {

    if (attvalue != value) return;

  } else if (operation == NEQ) {

    if (attvalue == value) return;

  } else if (operation == XOR) {

    if ((attvalue == 0.0 && value == 0.0) || 

        (attvalue != 0.0 && value != 0.0)) return;

  }

  // hard halt -> exit LAMMPS

  // also print ID of fix halt in case multiple ?

  if (eflag == HARD) error->all(FLERR,"Fix halt condition triggered");

  else { // eflag == SOFT

    if (comm->me == 0) error->message(FLERR,"Fix halt condition triggered");

    timer->force_timeout();

  }

}

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

double FixHalt::bondmax()

{

  // could add custom keyword methods

  // e.g. one to compute max bond length, with no sqrt()

  return 0.0;

}

/* -*- c++ -*- ----------------------------------------------------------

   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.

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

#ifdef FIX_CLASS

FixStyle(halt,FixHalt)

#else

#ifndef LMP_FIX_HALT_H

#define LMP_FIX_HALT_H

#include <stdio.h>

#include "fix.h"

namespace LAMMPS_NS {

class FixHalt : public Fix {

 public:

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

  ~FixHalt();

  int setmask();

  void init();

  void end_of_step();

 private:

  int attribute,operation,eflag,ivar;

  double attvalue,value;

  char *idvar;

  double bondmax();

};

}

#endif

#endif

/* ERROR/WARNING messages:

E: Illegal ... command

Self-explanatory.  Check the input script syntax and compare to the

documentation for the command.  You can use -echo screen as a

command-line option when running LAMMPS to see the offending line.

E: Cannot open fix print file %s

The output file generated by the fix print command cannot be opened

*/