/* -*- 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 PAIR_CLASS

PairStyle(vmm,PairVMM)

#else

#ifndef LMP_PAIR_VMM_H
#define LMP_PAIR_VMM_H

#include "pair.h"

namespace LAMMPS_NS {

class PairVMM : public Pair {
 public:
  PairVMM(class LAMMPS *);
  virtual ~PairVMM();
  virtual void compute(int, int);
  void settings(int, char **);
  virtual void coeff(int, char **);
  virtual double init_one(int, int);
  virtual void init_style();

  struct Param {                // Element_Symbol1	Element_Symbol2	We	W1	R01	B1	R02	B2	Rcut	cC1	cC2	force	De1.2	De1	De2	De3	De4	DeN	N
    double ideal_valence,k_vv,ideal_vv;   // This row corresponds to parameter values for only the ith atom.
    double w1;
    double r01,b1,r02,b2,c1,c2;
    double force_single,force_double,force_intercept,force_switch;
    double de_h1,de_k1,de_h2,de_k2,de_s02,de_h3,de_k3,de_s03;
    double rmin_a1,rmin_b1,rmin_c1,rmin_a2,rmin_b2,rmin_c2,rmin_a3,rmin_b3,rmin_c3,rmin_c0;
    double tol;                 // remove tol later
    double cut,cutsq;           //remove custsq later
    int ielement,jelement,kelement; //remove kelement
    int ielflag,jelflag;
    char isymbol[3],jsymbol[3];
  };
  
//  struct Bond {
//    double *smin;
//    int firststep;
//  };
  
 protected:
  double cutmax;                // max cutoff for all elements
  int nelements;                // # of unique elements
  char **elements;              // names of unique elements
  int **elem2param;            // mapping from element doublets to parameters
  int *map;                     // mapping from atom types to elements
  int nparams;                  // # of stored parameter sets
  int maxparam;                 // max # of parameter sets
  Param *params;                // parameter set for an I-J-K interaction
//  Bond *bonds;                  // temp holder for valence informaiton
  
  virtual void allocate();
  void read_file(char *);
  virtual void setup();
  int ncoord(int, double *, double, int *);
  void ovvsideal(int, int, double &, double &, double, double *, int *);
  void hvvsideal(int, int, double &, double &, double, double *, int *);
  void idealconfiguration(int, int, double, double *, double, int, int *, double *);
  int maxs(int, double *, int *);  
  double bondvalence(Param *, double);
//  double bvgrad(double, double, double, double, double, double);
  void vectorvalence(Param *, int, double *, double *, int, int *,  int, double, double, double, int *, 
                      double, double &, double &, double &);
  void nonbondedenergy(Param *, double, int, int, double &, double, double, double, double &, double &, double &,int);
  void valencemonopole(Param *, double , double, int, int, int, double &,  double, double, double, 
                      double *, double *, double *, double *, int, int,
                      double *, double *, double *, 
                      double, double, double, double &, double &, double &, int, int,int);
  void valencedipole(Param *, double, int, double &, 
                  double, double, double, double, double , double , double ,double,
                  double, double, double, double &, double &, double &, int);
  void nonbondedparameters(double &,double &, double &,int,int,int); 
};

}

#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: Incorrect args for pair coefficients

Self-explanatory.  Check the input script or data file.

E: Pair style Valence Multipole Model requires atom IDs

This is a requirement to use the VMM potential.

E: Pair style Valence Multipole Model requires newton pair on

See the newton command.  This is a restriction to use the VMM
potential.

E: All pair coeffs are not set

All pair coefficients must be set in the data file or by the
pair_coeff command before running a simulation.

E: Cannot open Valence Multipole Model potential file %s

The specified VMM potential file cannot be opened.  Check that the path
and name are correct.

E: Incorrect format in Valence Multipole Model potential file

Incorrect number of words per line in the potential file.

E: Illegal Valence Multipole Model parameter

One or more of the coefficients defined in the potential file is
invalid.

E: Potential file has duplicate entry

The potential file has more than one entry for the same element.

E: Potential file is missing an entry

The potential file does not have a needed entry.

*/