Scippy

SCIP

Solving Constraint Integer Programs

heur_locks.h
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1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
2 /* */
3 /* This file is part of the program and library */
4 /* SCIP --- Solving Constraint Integer Programs */
5 /* */
6 /* Copyright (C) 2002-2017 Konrad-Zuse-Zentrum */
7 /* fuer Informationstechnik Berlin */
8 /* */
9 /* SCIP is distributed under the terms of the ZIB Academic License. */
10 /* */
11 /* You should have received a copy of the ZIB Academic License */
12 /* along with SCIP; see the file COPYING. If not email to scip@zib.de. */
13 /* */
14 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
15 
16 /**@file heur_locks.h
17  * @ingroup PRIMALHEURISTICS
18  * @brief locks primal heuristic
19  * @author Michael Winkler
20  * @author Gerald Gamrath
21  *
22  * The locks heuristic is a start heuristic that first tries to fix all binary variables, then solves the resulting LP
23  * and tries to round the solution and finally solves a sub-MIP on the remaining problem if the LP solution could not be
24  * rounded. The fixing works as follows: First, all variables are sorted by their total number of rounding locks (up-
25  * and down-locks summed up). Then, looking at the variable with the highest number of locks first, the variable is
26  * fixed to the bound where there are fewer locks (in case of ties, the bound which is better w.r.t. the objective
27  * function). This fix is propagated and the activities of all LP rows are updated. If any LP row becomes redundant
28  * w.r.t. the updated bounds, we adjust the rounding locks.
29  */
30 
31 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
32 
33 #ifndef __SCIP_HEUR_LOCKS_H__
34 #define __SCIP_HEUR_LOCKS_H__
35 
36 
37 #include "scip/scip.h"
38 
39 #ifdef __cplusplus
40 extern "C" {
41 #endif
42 
43 /** creates the locks primal heuristic and includes it in SCIP
44  *
45  * @ingroup PrimalHeuristicIncludes
46  */
47 extern
49  SCIP* scip /**< SCIP data structure */
50  );
51 
52 #ifdef __cplusplus
53 }
54 #endif
55 
56 #endif
enum SCIP_Retcode SCIP_RETCODE
Definition: type_retcode.h:53
SCIP_RETCODE SCIPincludeHeurLocks(SCIP *scip)
Definition: heur_locks.c:968
SCIP callable library.