SCIP

Solving Constraint Integer Programs

heur_twoopt.h
Go to the documentation of this file.
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 /* */
9 /* you may not use this file except in compliance with the License. */
10 /* You may obtain a copy of the License at */
11 /* */
13 /* */
14 /* Unless required by applicable law or agreed to in writing, software */
16 /* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */
17 /* See the License for the specific language governing permissions and */
18 /* limitations under the License. */
19 /* */
20 /* You should have received a copy of the Apache-2.0 license */
21 /* along with SCIP; see the file LICENSE. If not visit scipopt.org. */
22 /* */
23 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
24
25 /**@file heur_twoopt.h
26  * @ingroup PRIMALHEURISTICS
27  * @brief Primal heuristic to improve incumbent solution by flipping pairs of variables
28  * @author Timo Berthold
29  * @author Gregor Hendel
30  *
31  * The Twoopt heuristic attempts to improve a feasible MIP solution by altering the solution values of pairs of
32  * variables. Only variables which share a pre-defined ratio of LP rows are considered as pairs. Each step of the
33  * heuristic consists of improving the objective value by shifting one variable, and then compensating the resulting
34  * infeasibilities by shifting a second variable, without completely losing the objective improvement. Similarly to
35  * Oneopt (see @ref heur_oneopt.h), pairs are processed in non-decreasing order of their impact on the objective.
36  */
37
38 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
39
40 #ifndef __SCIP_HEUR_TWOOPT_H__
41 #define __SCIP_HEUR_TWOOPT_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 twoopt primal 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
SCIP_RETCODE SCIPincludeHeurTwoopt(SCIP *scip)
Definition: heur_twoopt.c:1780
common defines and data types used in all packages of SCIP