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.         */
10   	/*  You may obtain a copy of the License at                                  */
11   	/*                                                                           */
12   	/*      http://www.apache.org/licenses/LICENSE-2.0                           */
13   	/*                                                                           */
14   	/*  Unless required by applicable law or agreed to in writing, software      */
15   	/*  distributed under the License is distributed on an "AS IS" BASIS,        */
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_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
56   	SCIP_RETCODE SCIPincludeHeurActconsdiving(
57   	   SCIP*                 scip                /**< SCIP data structure */
58   	   );
59   	
60   	#ifdef __cplusplus
61   	}
62   	#endif
63   	
64   	#endif
65