/*
 * force.h
 *
 * Define 'Force' struct and function prototypes.
 */

#ifndef FORCE_H
#define FORCE_H

#include "data.h"
#if 0
#include "mg.h"
#include "mgrid.h"
#include "dpmta.h"
#endif

#ifdef __cplusplus
extern "C" {
#endif


/*
 * forward declaration
 */
struct AtomBox_Tag;


/*
 * force computation object
 */
typedef struct Force_Tag {

  /* pointer back to main simulation data */
  Data *data;

  /* nonbonded forces */

    /*
     * pointer to routine to compute nonbonded forces
     */
  MD_Errcode (*compute_nonbonded)(struct Force_Tag *);

    /*
     * table for van der Waals force constants
     *
     * there are (4 * natomprms^2) entries in table that store
     * A, B, A_14, B_14 for each pairwise interaction type
     *
     * for an interaction between atoms itype and jtype,
     * table entry is:  4 * (itype * natomprms + jtype)
     *
     * the table is built during deven_force_init
     */
  double *vdwtable;

    /*
     * exclusion list for nonbonded interactions
     *
     * this is a jagged matrix with natoms rows, each row contains a
     * sorted list of atom numbers j for which atom numbered i has a
     * nonbonded exclusion; each row ends with sentinel INT_MAX
     *
     * list is built during deven_force_init based on the established
     * exclusion policy with up to 1-4 exclusions depending on simparam
     * setting (if scaled 1-4 interactions are in effect, then list
     * contains only 1-2 and 1-3 exclusions)
     */
  MD_Int **excllist;

    /*
     * scaled 1-4 exclusion list
     *
     * same as above except that this list contains only 1-4 exclusions
     */
  MD_Int **scaled14;

    /*
     * nonbonded force constants
     */
  double elec_const;
  double cutoff2;
  double inv_cutoff2;
  double switchdist2;
  double sw_denom;
  double sw_denom_times_four;
  MD_Int is_switching;

    /*
     * cutoff force evaluation
     */
  struct AtomBox_Tag *atombox;
  MD_Int numbox;
  MD_Int nxbox, nybox, nzbox;
  double xmin, ymin, zmin;
  double inv_xboxsize, inv_yboxsize, inv_zboxsize;
  double xextent, yextent, zextent;

    /*
     * spherical boundary condition constants
     */
  MD_Int is_sphericalbc;
  MD_Dvec center;
  double r1, k1, r2, k2;
  MD_Int p1, p2;

#if 0
    /*
     * parameters to MG routines
     */
  Params mg_params;
  double **mg_f;
  double **mg_pos;
  double *mg_q;

    /*
     * parameters to mgrid routines
     */
  Mgrid *mgrid;
  MgridParams mgrid_params;
  MgridSystem mgrid_system;
  double *mgrid_q;

    /*
     * parameters to DPMTA routines
     */
  PmtaInitData pmta_init_data;
  PmtaParticle *pmta_particle;
  PmtaPartInfo *pmta_result;
#endif

    /*
     * nonbonded potentials
     */
  double pe_elec;
  double pe_vdw;
} Force;


/*
 * prototypes
 */
MD_Errcode deven_force_init(Force *force, Data *data);
MD_Errcode deven_force_compute(Force *force);
void deven_force_destroy(Force *force);


#ifdef __cplusplus
}
#endif

#endif /* FORCE_H */