/* -*- 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.
------------------------------------------------------------------------- */

#ifndef LMP_DIHEDRAL_H
#define LMP_DIHEDRAL_H

#include "pointers.h"  // IWYU pragma: export

namespace LAMMPS_NS {

class Dihedral : protected Pointers {
  friend class ThrOMP;
  friend class FixOMP;
 public:
  int allocated;
  int *setflag;
  int writedata;                     // 1 if writes coeffs to data file
  double energy;                     // accumulated energy
  double virial[6];                  // accumulated virial
  double *eatom,**vatom;             // accumulated per-atom energy/virial
  double **cvatom;                   // accumulated per-atom centroid virial

  int centroidstressflag;        // centroid stress compared to two-body stress
                                 // CENTROID_SAME = same as two-body stress
                                 // CENTROID_AVAIL = different and implemented
                                 // CENTROID_NOTAVAIL = different, not yet implemented

  // KOKKOS host/device flag and data masks

  ExecutionSpace execution_space;
  unsigned int datamask_read,datamask_modify;
  int copymode;

  Dihedral(class LAMMPS *);
  virtual ~Dihedral();
  virtual void init();
  virtual void init_style() {}
  virtual void compute(int, int) = 0;
  virtual void settings(int, char **) {}
  virtual void coeff(int, char **) = 0;
  virtual void write_restart(FILE *) = 0;
  virtual void read_restart(FILE *) = 0;
  virtual void write_restart_settings(FILE *) {};
  virtual void read_restart_settings(FILE *) {};
  virtual void write_data(FILE *) {}
  virtual double memory_usage();

 protected:
  int suffix_flag;             // suffix compatibility flag

  int evflag;
  int eflag_either,eflag_global,eflag_atom;
  int vflag_either,vflag_global,vflag_atom,cvflag_atom;
  int maxeatom,maxvatom,maxcvatom;

  void ev_init(int eflag, int vflag, int alloc = 1) {
    if (eflag||vflag) ev_setup(eflag, vflag, alloc);
    else evflag = eflag_either = eflag_global = eflag_atom = vflag_either = vflag_global = vflag_atom = cvflag_atom = 0;
  }
  void ev_setup(int, int, int alloc = 1);
  void ev_tally(int, int, int, int, int, int, double,
                double *, double *, double *, double, double, double,
                double, double, double, double, double, double);
};

}

#endif

/* ERROR/WARNING messages:

E: Dihedral coeffs are not set

No dihedral coefficients have been assigned in the data file or via
the dihedral_coeff command.

E: All dihedral coeffs are not set

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

*/
