gromacs-dev 4.6.5-1build1 / usr / include / gromacs / split.h

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#ifndef _split_h
#define _split_h

/*
 * Determine on which node a particle should reside and on which
 * node is also should be available. The distribution algorithm
 * should account for the actual ring architecture and how nodes
 * are numbered. The typedef t_splitd has two separate structures that
 * describe the distribution:
 *
 * The nodeinfo part describes which node containst which particles,
 * while the nodeids part describes on which node(s) a particle can be
 * found and what local particle number is assigned to it.
 *
 */

#include <stdio.h>
#include "typedefs.h"

#ifdef __cplusplus
extern "C" {
#endif

typedef enum {
    SPLIT_NONE, SPLIT_SORTX, SPLIT_REDUCE, SPLIT_NR
} t_splitalg;

typedef struct
{
    int      hid;
    atom_id *nodeid;
} t_nodeids;

typedef struct
{
    int  nr;    /* Length of the long list.                         */
    int *lst;   /* The actual list.                                 */
} t_nlist;

typedef struct
{
    t_nlist home;   /* List of home particles.                          */
} t_nodeinfo;

typedef struct
{
    int         nnodes;   /* Number of nodes this splitinfo is for.      */
    t_nodeinfo *nodeinfo; /* Home and available particles for each node. */
    int         nnodeids; /* Number of particles this splitinfo is for.       */
    t_nodeids  *nodeids;  /* List of node id's for every particle,       */
    /* entry[nodeid] gives the local atom id (NO_ATID if*/
    /* not available). Entry[MAXNODES] contains home    */
    /* node's id.                                  */
} t_splitd;

void init_splitd(t_splitd *splitd, int nnodes, int nnodeids);
/*
 * Initialises the splitd data structure for the specified number of
 * nodes (nnodes) and number of atoms (nnodeids).
 */

void make_splitd(t_splitalg algorithm, int nnodes, t_topology *top,
                 rvec *x, t_splitd *splitd, char *loadfile);
/*
 * Initialises the splitd data structure for the specified number of
 * nodes (nnodes) and number of atoms (top) and fills it using
 * the specified algorithm (algorithm):
 *
 *    SPLIT_NONE   : Generate partial systems by dividing it into nnodes
 *                   consecutive, equal, parts without any intelligence.
 *    SPLIT_SORTX  : Like SPLIT_NONE but sort the coordinates before
 *                   dividing the system into nnodes consecutive, equal,
 *                   parts.
 *    SPLIT_REDUCE : Like SPLIT_NONE but minimise the bond lengths, i.e
 *                   invoke the reduce algorithm before dividing the
 *                   system into nnodes consecutive, equal, parts.
 *
 * The topology (top) and the coordinates (x) are not modified. The
 * calculations of bonded forces are assigned to the node with
 * the highest id that has one of the needed particles as home particle.
 */

long wr_split(FILE *fp, t_splitd *splitd);
/*
 * Writes the split descriptor (splitd) to the file specified by fp.
 */

long rd_split(FILE *fp, t_splitd *splitd);
/*
 * Reads the split descriptor (splitd) from the file specified by fp.
 */

void rm_splitd(t_splitd *splitd);
/*
 * Frees all allocated space for the splitd data structure.
 */

void pr_splitd(FILE *fp, int indent, char *title, t_splitd *splitd);
/*
 * This routine prints out a (human) readable representation of
 * the split descriptor to the file fp. Ident specifies the
 * number of spaces the text should be indented. Title is used
 * to print a header text.
 */

void split_topology(t_splitalg algorithm, int nnodes, t_topology *top,
                    rvec x[], char *loadfile);
/*
 * Distributes the non-bonded forces defined in top over nnodes nodes
 * using the algoritm specified by algorithm. The distribution is made
 * by creating a split descriptor and then putting a bonded force on the
 * highest home node number of the paricles involved.
 */

#ifdef __cplusplus
}
#endif

#endif  /* _split_h */