src/gromacs/topology/ifunc.h

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  37 #ifndef GMX_TOPOLOGY_IFUNC_H
  38 #define GMX_TOPOLOGY_IFUNC_H
  39
  40 #include "gromacs/topology/idef.h"
  41
  42 #ifdef __cplusplus
  43 extern "C" {
  44 #endif
  45
  46 struct t_fcdata;
  47 struct t_graph;
  48 struct t_mdatoms;
  49 struct t_pbc;
  50
  51 /* Real vector type with an additional, unused 4th element.
  52  * This type is used to allow aligned 4-wide SIMD loads and stores.
  53  */
  54 typedef real rvec4[4];
  55
  56 typedef real t_ifunc (int nbonds, const t_iatom iatoms[],
  57                       const t_iparams iparams[],
  58                       const rvec x[], rvec4 f[], rvec fshift[],
  59                       const struct t_pbc *pbc, const struct t_graph *g,
  60                       real lambda, real *dvdlambda,
  61                       const struct t_mdatoms *md, struct t_fcdata *fcd,
  62                       int *ddgatindex);
  63
  64 /*
  65  * The function type t_ifunc() calculates one interaction, using iatoms[]
  66  * and iparams. Within the function the number of atoms to be used is
  67  * known. Within the function only the atomid part of the iatoms[] array
  68  * is supplied, not the type field (see also t_ilist). The function
  69  * returns the potential energy. If pbc==NULL the coordinates in x are
  70  * assumed to be such that no calculation of PBC is necessary,
  71  * If pbc!=NULL a full PBC calculation is performed.
  72  * If g!=NULL it is used for determining the shift forces.
  73  * With domain decomposition ddgatindex can be used for getting global
  74  * atom numbers for warnings and error messages.
  75  * ddgatindex is NULL when domain decomposition is not used.
  76  */
  77
  78 #define IF_NULL       0
  79 #define IF_BOND       1
  80 #define IF_VSITE      1<<1
  81 #define IF_CONSTRAINT 1<<2
  82 #define IF_CHEMBOND   1<<3
  83 #define IF_BTYPE      1<<4
  84 #define IF_ATYPE      1<<5
  85 #define IF_TABULATED  1<<6
  86 #define IF_LIMZERO    1<<7
  87 /* These flags tell to some of the routines what can be done with this
  88  * item in the list.
  89  * With IF_BOND a bonded interaction will be calculated.
  90  * With IF_BTYPE grompp can convert the bond to a Morse potential.
  91  * With IF_BTYPE or IF_ATYPE the bond/angle can be converted to
  92  * a constraint or used for vsite parameter determination by grompp.
  93  * IF_LIMZERO indicates that for a bonded interaction the potential
  94  * does goes to zero for large distances, thus if such an interaction
  95  * it not assigned to any node by the domain decompostion, the simulation
  96  * still continue, if mdrun has been told so.
  97  */
  98 typedef struct
  99 {
 100     const char *name;         /* the name of this function                      */
 101     const char *longname;     /* The name for printing etc.                   */
 102     int         nratoms;      /* nr of atoms needed for this function           */
 103     int         nrfpA, nrfpB; /* number of parameters for this function.      */
 104                               /* this corresponds to the number of params in  */
 105                               /* iparams struct! (see idef.h)                 */
 106     /* A and B are for normal and free energy components respectively.    */
 107     unsigned long   flags;    /* Flags (see above)                            */
 108     int             nrnb_ind; /* index for nrnb (-1 if unknown)               */
 109     t_ifunc        *ifunc;    /* the function it self                           */
 110 } t_interaction_function;
 111
 112 #define NRFPA(ftype) (interaction_function[(ftype)].nrfpA)
 113 #define NRFPB(ftype) (interaction_function[(ftype)].nrfpB)
 114 #define NRFP(ftype)  (NRFPA(ftype)+NRFPB(ftype))
 115 #define NRAL(ftype) (interaction_function[(ftype)].nratoms)
 116
 117 #define IS_CHEMBOND(ftype) (interaction_function[(ftype)].nratoms == 2 && (interaction_function[(ftype)].flags & IF_CHEMBOND))
 118 /* IS_CHEMBOND tells if function type ftype represents a chemical bond */
 119
 120 /* IS_ANGLE tells if a function type ftype represents an angle
 121  * Per Larsson, 2007-11-06
 122  */
 123 #define IS_ANGLE(ftype) (interaction_function[(ftype)].nratoms == 3 && (interaction_function[(ftype)].flags & IF_ATYPE))
 124 #define IS_VSITE(ftype) (interaction_function[(ftype)].flags & IF_VSITE)
 125
 126 #define IS_TABULATED(ftype) (interaction_function[(ftype)].flags & IF_TABULATED)
 127
 128 extern const t_interaction_function interaction_function[F_NRE];
 129 /* initialised interaction functions descriptor                         */
 130
 131 #ifdef __cplusplus
 132 }
 133 #endif
 134
 135 #endif