nblist.h

/* -------------------------------------------------------------------------- *
 * copyright (c) 2014-2015 Emilio Gallicchio                                  *
 * Authors: Emilio Gallicchio <egallicchio@brooklyn.cuny.edu>                 *
 * Contributors:                                                              *
 *                                                                            *
 *  This program is free software: you can redistribute it and/or modify      *
 *  it under the terms of the GNU Lesser General Public License version 3     *
 *  as published by the Free Software Foundation.                             *
 *                                                                            *
 *  The program is distributed in the hope that it will be useful,            *
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of            *
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             *
 *  GNU General Public License for more details.                              *
 *                                                                            *
 *  You should have received a copy of the GNU General Public License         *
 *  along this program.  If not, see <http://www.gnu.org/licenses/>.          *
 *                                                                            *
 * -------------------------------------------------------------------------- */

#ifndef LIBNBLIST_H
#define LIBNBLIST_H
#ifdef __cplusplus
extern "C" {
#endif

/* return codes */
#define NBLIST_OK 0
#define NBLIST_ERR 1

/*                                                                   *
 * a simple interface to create/reallocate a Verlet neighbor list    *
 *                                                                   */

typedef struct vector_ { /* A 3D vector */
  double x, y, z;
} NeighVector;

/* neighbor list structure */
typedef struct neighlist_ {
  /* number of atoms */
  int natoms;
  /* neighbor list size */
  int neighl_size;
  /* number of neighbors for each atom */
  int *nne;
  /* where the actual atom indexes are stored */
  int *neighl1;
  /* pointer into neighl1 for each atom, neighbors of atom iat are retrived
     as jat=neighl[iat][j] ; 0 <= i < nne[iat] */ 
  int **neighl;

  int idx_remap; /* whether (yes > 0, no = 0) to do atom indexes remapping */
  int *int2ext; /* an optional map to translate from internal to external
		   atom indeces */
  int *ext2int; /* an optional map to translate from external to internal
		   atom indeces */

  /* flag, if not zero neighbor list contains PBC translation vectors */
  int pbc;
  /* same as neighl and neighl1 but stores PBC translation vectors */
  NeighVector  *pbc_trans1;
  NeighVector  **pbc_trans;

  /* additional data  */
  int data; /* flag, if not zero additional data exists */
  /* same as neighl and neighl1 but for additional data */
  void  **data_index1; /* pointers to anything */
  void  ***data_index;

} NeighList;

/* function prototypes */

/* reset neighbor list */
void nblist_reset_neighbor_list(NeighList *neigh_list);
/* delete neighbor list */
void nblist_delete_neighbor_list(NeighList *neigh_list);
/* reallocates neighbor list */
int nblist_reallocate_neighbor_list(NeighList *neigh_list, 
				     int natoms, int size);

#ifdef __cplusplus
}
#endif
#endif