nsz Git - libfirm/blob - include/libfirm/adt/hungarian.h

   1 /********************************************************************
   2  ********************************************************************
   3  **
   4  ** libhungarian by Cyrill Stachniss, 2004
   5  **
   6  ** Added to libFirm by Christian Wuerdig, 2006
   7  ** Added several options for not-perfect matchings.
   8  **
   9  ** Solving the Minimum Assignment Problem using the
  10  ** Hungarian Method.
  11  **
  12  ** ** This file may be freely copied and distributed! **
  13  **
  14  ** Parts of the used code was originally provided by the
  15  ** "Stanford GraphGase", but I made changes to this code.
  16  ** As asked by  the copyright node of the "Stanford GraphGase",
  17  ** I hereby proclaim that this file are *NOT* part of the
  18  ** "Stanford GraphGase" distribution!
  19  **
  20  ** This file is distributed in the hope that it will be useful,
  21  ** but WITHOUT ANY WARRANTY; without even the implied
  22  ** warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  23  ** PURPOSE.
  24  **
  25  ********************************************************************
  26  ********************************************************************/
  27
  28 /**
  29  * @file
  30  * @brief   Solving the Minimum Assignment Problem using the Hungarian Method.
  31  */
  32 #ifndef FIRM_ADT_HUNGARIAN_H
  33 #define FIRM_ADT_HUNGARIAN_H
  34
  35 #include "../begin.h"
  36
  37 typedef enum match_type_t {
  38         HUNGARIAN_MATCH_NORMAL,   /**< ever nodes matches another node */
  39         HUNGARIAN_MATCH_PERFECT   /**< matchings of nodes having no edge getting
  40                                        removed */
  41 } match_type_t;
  42
  43 typedef enum hungarian_mode_t {
  44         HUNGARIAN_MODE_MINIMIZE_COST,
  45         HUNGARIAN_MODE_MAXIMIZE_UTIL
  46 } hungarian_mode_t;
  47
  48 typedef struct hungarian_problem_t hungarian_problem_t;
  49
  50 /**
  51  * This method initialize the hungarian_problem structure and init
  52  * the cost matrix (missing lines or columns are filled with 0).
  53  *
  54  * @param num_rows   Number of rows in the given matrix
  55  * @param num_cols   Number of cols in the given matrix
  56  * @param match_type The type of matching
  57  * @return The problem object.
  58  */
  59 FIRM_API hungarian_problem_t *hungarian_new(unsigned num_rows,
  60                                             unsigned num_cols,
  61                                             match_type_t match_type);
  62
  63 /**
  64  * Adds an edge from left to right with some costs.
  65  */
  66 FIRM_API void hungarian_add(hungarian_problem_t *p, unsigned left,
  67                             unsigned right, unsigned cost);
  68
  69 /**
  70  * Removes the edge from left to right.
  71  */
  72 FIRM_API void hungarian_remove(hungarian_problem_t *p, unsigned left,
  73                                unsigned right);
  74
  75 /**
  76  * Prepares the cost matrix dependent on the given mode.
  77  *
  78  * @param p     The hungarian object
  79  * @param mode  specify whether to minimize or maximize the costs
  80  */
  81 FIRM_API void hungarian_prepare_cost_matrix(hungarian_problem_t *p,
  82                                             hungarian_mode_t mode);
  83
  84 /**
  85  * Destroys the hungarian object.
  86  */
  87 FIRM_API void hungarian_free(hungarian_problem_t *p);
  88
  89 /**
  90  * This method computes the optimal assignment.
  91  * @param p              The hungarian object
  92  * @param assignment     The final assignment
  93  * @param final_cost     The final costs
  94  * @param cost_threshold Matchings with costs >= this limit will be removed (if limit > 0)
  95  * @return 0 on success, negative number otherwise
  96  */
  97 FIRM_API int hungarian_solve(hungarian_problem_t *p, unsigned *assignment,
  98                              unsigned *final_cost, unsigned cost_threshold);
  99
 100 /**
 101  * Print the cost matrix.
 102  * @param p          The hungarian object
 103  * @param cost_width The minimum field width of the costs
 104  */
 105 FIRM_API void hungarian_print_cost_matrix(hungarian_problem_t *p,
 106                                           int cost_width);
 107
 108 #include "../end.h"
 109
 110 #endif