Scippy

SCIP

Solving Constraint Integer Programs

heur_actconsdiving.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) 2002-2023 Zuse Institute Berlin (ZIB) */
7 /* */
8 /* Licensed under the Apache License, Version 2.0 (the "License"); */
9 /* you may not use this file except in compliance with the License. */
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19 /* */
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21 /* along with SCIP; see the file LICENSE. If not visit scipopt.org. */
22 /* */
23 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
24 
25 /**@file heur_actconsdiving.h
26  * @ingroup PRIMALHEURISTICS
27  * @brief LP diving heuristic that chooses fixings w.r.t. the active constraints the variable appear in
28  * @author Tobias Achterberg
29  *
30  * Diving heuristic: Iteratively fixes some fractional variable and resolves the LP-relaxation, thereby simulating a
31  * depth-first-search in the tree. Active Constraint Diving chooses a variable based on the active LP rows (equations
32  * are counted twice here). The variable score is calculated as a convex combination of the number of constraints the
33  * variable appears in, the sum of all positive coefficients and the absolute sum of all negative coefficients. The
34  * chosen variable is then rounded to the closest integer. One-level backtracking is applied: If the LP gets infeasible,
35  * the last fixings is undone, and the opposite fixing is tried. If this is infeasible, too, the procedure aborts.
36  */
37 
38 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
39 
40 #ifndef __SCIP_HEUR_ACTCONSDIVING_H__
41 #define __SCIP_HEUR_ACTCONSDIVING_H__
42 
43 #include "scip/def.h"
44 #include "scip/type_retcode.h"
45 #include "scip/type_scip.h"
46 
47 #ifdef __cplusplus
48 extern "C" {
49 #endif
50 
51 /** creates the actconsdiving heuristic and includes it in SCIP
52  *
53  * @ingroup PrimalHeuristicIncludes
54  */
55 SCIP_EXPORT
57  SCIP* scip /**< SCIP data structure */
58  );
59 
60 #ifdef __cplusplus
61 }
62 #endif
63 
64 #endif
enum SCIP_Retcode SCIP_RETCODE
Definition: type_retcode.h:63
type definitions for return codes for SCIP methods
type definitions for SCIP&#39;s main datastructure
common defines and data types used in all packages of SCIP
SCIP_RETCODE SCIPincludeHeurActconsdiving(SCIP *scip)