fparam.h

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/*
 * Copyright (C) 2004-2006 by David J. Hardy.  All rights reserved.
 */

#ifndef FPARAM_H
#define FPARAM_H

#include <float.h>
#include "mdapi/mdtypes.h"

#ifdef __cplusplus
extern "C" {
#endif

  typedef struct ForceParam_t {

    /* Force field parameters as defined by the MDAPI mdtypes.h file. */
    MD_AtomPrm *atomprm;   
    MD_BondPrm *bondprm;   
    MD_AnglePrm *angleprm; 
    MD_TorsPrm *dihedprm;  
    MD_TorsPrm *imprprm;   
    MD_NbfixPrm *nbfixprm; 
    int32 atomprm_len;     
    int32 bondprm_len;     
    int32 angleprm_len;    
    int32 dihedprm_len;    
    int32 imprprm_len;     
    int32 nbfixprm_len;    
    /* Topology parameters as defined by the MDAPI mdtypes.h file. */
    MD_Atom *atom;         
    MD_Bond *bond;         
    MD_Angle *angle;       
    MD_Tors *dihed;        
    MD_Tors *impr;         
    MD_Excl *excl;         
    int32 atom_len;   
    int32 bond_len;        
    int32 angle_len;       
    int32 dihed_len;       
    int32 impr_len;        
    int32 excl_len;        
    /* parameters for pairwise potentials */
    double cutoff;         
    double elec_cutoff;    
    double vdw_cutoff;     
    double switchdist;     
    double elec_const;     
    double dielectric;     
    double scaling14;      
    double ewald_coef;     
    /* boundary restraints defined around center */
    double radius1;        
    double radius2;        
    double length1;        
    double length2;        
    double konst1;         
    double konst2;         
    int32 exp1;            
    int32 exp2;            
    /* options */
    int32 forcetypes;      
    int32 exclpolicy;      
    int32 elecopts;        
    int32 vdwopts;         
    int32 bresopts;        
    /* algorithmic parameters */
    int32 shell_width;     
    double cutoff_ratio;   
    double delta_dis;      
    double cell_margin;    
  } ForceParam;


  enum ForceTypes_t {
    FORCE_NONE        = 0x0000,
    FORCE_BOND        = 0x0001,
    FORCE_ANGLE       = 0x0002,
    FORCE_DIHED       = 0x0004,
    FORCE_IMPR        = 0x0008,
    FORCE_ELEC        = 0x0010,
    FORCE_VDW         = 0x0020,
    FORCE_BRES        = 0x0040,
    FORCE_BONDED      = FORCE_BOND | FORCE_ANGLE | FORCE_DIHED | FORCE_IMPR,
    FORCE_PAIRWISE    = FORCE_ELEC | FORCE_VDW,
    FORCE_NONBONDED   = FORCE_PAIRWISE | FORCE_BRES,
    FORCE_ALL         = FORCE_BONDED | FORCE_NONBONDED
  };


  /*@brief Nonbonded exclusion policy, mutually exclusive. */
  enum ForceExcl_t {
    FORCE_EXCL_NONE   = 0x001,
    FORCE_EXCL_12,
    FORCE_EXCL_13,
    FORCE_EXCL_14,
    FORCE_EXCL_SCAL14,
    FORCE_MARKER_EXCL
  };


  /*@brief Electrostatics options, choose both the method and potential. */
  enum ForceElec_t {

  /* methods */
    FORCE_ELEC_DIRECT    = 0x001,
    FORCE_ELEC_GRIDCELLS = 0x002,
    FORCE_ELEC_PAIRLISTS = 0x004,
    FORCE_ELEC_STNDEXCL  = 0x008,
  /* pair potentials */
    FORCE_ELEC_STANDARD  = 0x010,
    FORCE_ELEC_SHIFTED   = 0x020,
    FORCE_ELEC_EWALD     = 0x040,
    FORCE_ELEC_GLASS     = 0x080,

  /* bit masks */
    FORCE_MASK_ELEC_METHOD    = 0x00f,
    FORCE_MASK_ELEC_POTENTIAL = 0x0f0,
  /* typical values for elecopts */
    FORCE_ELECOPTS_DIRECT = FORCE_ELEC_DIRECT | FORCE_ELEC_STANDARD,
    FORCE_ELECOPTS_CUTOFF = FORCE_ELEC_GRIDCELLS | FORCE_ELEC_SHIFTED,
    FORCE_ELECOPTS_LONGRNG = FORCE_ELEC_STNDEXCL
  };


  /*@brief Van der Waals options, choose both the method and potential. */
  enum ForceVdw_t {

  /* methods */
    FORCE_VDW_DIRECT     = 0x0001,
    FORCE_VDW_GRIDCELLS  = 0x0002,
    FORCE_VDW_PAIRLISTS = 0x004,
    FORCE_VDW_STNDEXCL   = 0x0008,
  /* pair potentials */
    FORCE_VDW_STANDARD   = 0x0010,
    FORCE_VDW_SWITCHED   = 0x0020,
    FORCE_VDW_BUCK       = 0x0040,
    FORCE_VDW_SWITCHBUCK = 0x0080,
    FORCE_VDW_BUCKND     = 0x0100,
    FORCE_VDW_SWITCHBUCKND=0x0200,
    FORCE_VDW_BUCKSAFE    =0x0400,
    FORCE_VDW_SWITCHBUCKSAFE=0x0800,
    FORCE_VDW_GLASS        =0x1000,

  /* select Buckingham parameterization */
    FORCE_VDW_BUCKPRM_BKS  =0x10000,
    FORCE_VDW_BUCKPRM_TTAM =0x20000,
    FORCE_VDW_BUCKPRM_FB   =0x40000,
    FORCE_VDW_GLASSPRM     =0x80000,

  /* bit masks */
    FORCE_MASK_VDW_METHOD     = 0x000f,
    FORCE_MASK_VDW_POTENTIAL  = 0x1ff0,
    FORCE_MASK_VDW_BUCK       = 0x1fc0,
    FORCE_MASK_VDW_BUCKPRM    = 0xf0000,
  /* typical values for vdwopts */
    FORCE_VDWOPTS_DIRECT = FORCE_VDW_DIRECT | FORCE_VDW_STANDARD,
    FORCE_VDWOPTS_CUTOFF = FORCE_VDW_GRIDCELLS | FORCE_VDW_SWITCHED,
    FORCE_VDWOPTS_LONGRNG = FORCE_VDW_STNDEXCL
  };


  /*@brief Boundary restraints, mutually exclusive
   * (generally intended for nonperiodic systems). */
  enum ForceBrestype_t {
    FORCE_BRES_SPHERE = 0x001,
    FORCE_BRES_X_CYLINDER,
    FORCE_BRES_Y_CYLINDER,
    FORCE_BRES_Z_CYLINDER,
    FORCE_MARKER_BRES
  };


  /*@brief Algorithmic parameter defaults.
   *
   * With all parameters present, the extended cutoff should be @n
   *
   *   cutoff + 2*delta_dis <=
   *       shell_width * ( cutoff_ratio * (cutoff + 2*delta_dis) + cell_margin)
   *
   * For grid cell hashing exclusively, set delta_dis = cell_margin = 0.
   * For pair lists generated using grid cells, delta_dis controls how
   * often the pair lists need to be generated.
   *
   * cutoff_ratio tunes the coverage of the (extended) cutoff across
   * the shell width, and cell_margin can be adjusted to make cells a
   * little bigger (so hashing more atoms per cell) independently of
   * the size of the cutoff.
   */
#define FORCE_DEFAULT_SHELL_WIDTH          3
#define FORCE_DEFAULT_CUTOFF_RATIO         (1./FORCE_DEFAULT_SHELL_WIDTH)
#define FORCE_DEFAULT_CELL_MARGIN          FLT_EPSILON
#define FORCE_DEFAULT_PAIRLIST_DELTA_DIS   0.75
#define FORCE_DEFAULT_GRIDCELL_DELTA_DIS   0.0


  /* force param constructor and destructor */

  ForceParam *force_param_create(void);

  void force_param_destroy(ForceParam *);


  int force_param_initialize(ForceParam *);

  void force_param_cleanup(ForceParam *);


#ifdef __cplusplus
}
#endif

#endif /* FPARAM_H */

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