include/types/ifunc.h

   1 /*
   2  *
   3  *                This source code is part of
   4  *
   5  *                 G   R   O   M   A   C   S
   6  *
   7  *          GROningen MAchine for Chemical Simulations
   8  *
   9  *                        VERSION 3.2.0
  10  * Written by David van der Spoel, Erik Lindahl, Berk Hess, and others.
  11  * Copyright (c) 1991-2000, University of Groningen, The Netherlands.
  12  * Copyright (c) 2001-2004, The GROMACS development team,
  13  * check out http://www.gromacs.org for more information.
  14
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version 2
  18  * of the License, or (at your option) any later version.
  19  *
  20  * If you want to redistribute modifications, please consider that
  21  * scientific software is very special. Version control is crucial -
  22  * bugs must be traceable. We will be happy to consider code for
  23  * inclusion in the official distribution, but derived work must not
  24  * be called official GROMACS. Details are found in the README & COPYING
  25  * files - if they are missing, get the official version at www.gromacs.org.
  26  *
  27  * To help us fund GROMACS development, we humbly ask that you cite
  28  * the papers on the package - you can find them in the top README file.
  29  *
  30  * For more info, check our website at http://www.gromacs.org
  31  *
  32  * And Hey:
  33  * GRoups of Organic Molecules in ACtion for Science
  34  */
  35 #ifdef HAVE_CONFIG_H
  36 #include <config.h>
  37 #endif
  38
  39 #ifndef _ifunc_h
  40 #define _ifunc_h
  41
  42 #ifdef __cplusplus
  43 extern "C" {
  44 #endif
  45
  46
  47 typedef real t_ifunc(int nbonds,const t_iatom iatoms[],
  48                      const t_iparams iparams[],
  49                      const rvec x[],rvec f[],rvec fshift[],
  50                      const t_pbc *pbc,const t_graph *g,
  51                      real lambda,real *dvdlambda,
  52                      const t_mdatoms *md,t_fcdata *fcd,
  53                      int *ddgatindex);
  54
  55 /*
  56  * The function type t_ifunc() calculates one interaction, using iatoms[]
  57  * and iparams. Within the function the number of atoms to be used is
  58  * known. Within the function only the atomid part of the iatoms[] array
  59  * is supplied, not the type field (see also t_ilist). The function
  60  * returns the potential energy. If pbc==NULL the coordinates in x are
  61  * assumed to be such that no calculation of PBC is necessary,
  62  * If pbc!=NULL a full PBC calculation is performed.
  63  * If g!=NULL it is used for determining the shift forces.
  64  * With domain decomposition ddgatindex can be used for getting global
  65  * atom numbers for warnings and error messages.
  66  * ddgatindex is NULL when domain decomposition is not used.
  67  */
  68
  69 #define IF_NULL       0
  70 #define IF_BOND       1
  71 #define IF_VSITE      1<<1
  72 #define IF_CONSTRAINT 1<<2
  73 #define IF_CHEMBOND   1<<3
  74 #define IF_BTYPE      1<<4
  75 #define IF_ATYPE      1<<5
  76 #define IF_TABULATED  1<<6
  77 #define IF_LIMZERO    1<<7
  78 /* These flags tell to some of the routines what can be done with this
  79  * item in the list.
  80  * With IF_BOND a bonded interaction will be calculated.
  81  * With IF_BTYPE grompp can convert the bond to a Morse potential.
  82  * With IF_BTYPE or IF_ATYPE the bond/angle can be converted to
  83  * a constraint or used for vsite parameter determination by grompp.
  84  * IF_LIMZERO indicates that for a bonded interaction the potential
  85  * does goes to zero for large distances, thus if such an interaction
  86  * it not assigned to any node by the domain decompostion, the simulation
  87  * still continue, if mdrun has been told so.
  88  */
  89 typedef struct
  90 {
  91   const char *name;     /* the name of this function                    */
  92   const char *longname; /* The name for printing etc.                   */
  93   int     nratoms;      /* nr of atoms needed for this function         */
  94   int     nrfpA,nrfpB;  /* number of parameters for this function.      */
  95                         /* this corresponds to the number of params in  */
  96                         /* iparams struct! (see idef.h)                 */
  97   /* A and B are for normal and free energy components respectively.    */
  98   unsigned long   flags;        /* Flags (see above)                            */
  99   int     nrnb_ind;     /* index for nrnb (-1 if unknown)               */
 100   t_ifunc *ifunc;       /* the function it self                         */
 101 } t_interaction_function;
 102
 103 #define NRFPA(ftype) (interaction_function[(ftype)].nrfpA)
 104 #define NRFPB(ftype) (interaction_function[(ftype)].nrfpB)
 105 #define NRFP(ftype)  (NRFPA(ftype)+NRFPB(ftype))
 106 #define NRAL(ftype) (interaction_function[(ftype)].nratoms)
 107
 108 #define IS_CHEMBOND(ftype) (interaction_function[(ftype)].nratoms==2 && interaction_function[(ftype)].flags & IF_CHEMBOND)
 109 /* IS_CHEMBOND tells if function type ftype represents a chemical bond */
 110
 111 /* IS_ANGLE tells if a function type ftype represents an angle
 112  * Per Larsson, 2007-11-06
 113  */
 114 #define IS_ANGLE(ftype) (interaction_function[(ftype)].nratoms==3 && interaction_function[(ftype)].flags & IF_ATYPE)
 115 #define IS_VSITE(ftype) (interaction_function[(ftype)].flags & IF_VSITE)
 116
 117 #define IS_TABULATED(ftype) (interaction_function[(ftype)].flags & IF_TABULATED)
 118
 119 extern const t_interaction_function interaction_function[F_NRE];
 120 /* initialised interaction functions descriptor                         */
 121
 122 #ifdef __cplusplus
 123 }
 124 #endif
 125
 126
 127 #endif