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   reader_dec.h
26   	 * @ingroup FILEREADERS
27   	 * @brief  file reader for decompositions in the constraint based dec-file format.
28   	 * @author Gregor Hendel
29   	 *
30   	 *
31   	 * This reader allows to read a file containing decompositions for constraints of the current original problem. The
32   	 * standard line ending for this format is '.dec'. The content of the file should obey the following format
33   	 *
34   	 *     \\ place for comments and statistics
35   	 *     NBLOCKS
36   	 *     2
37   	 *     BLOCK 0
38   	 *     consA
39   	 *     consB
40   	 *     [...]
41   	 *     BLOCK 1
42   	 *     consC
43   	 *     consD
44   	 *     [...]
45   	 *     MASTERCONSS
46   	 *     linkingcons
47   	 *
48   	 * A block in a problem decomposition is a set of constraints that are independent from all other blocks after removing
49   	 * the special blocks of linking constraints denoted as MASTERCONSS.
50   	 *
51   	 * Imagine the following example, which involves seven variables
52   	 * and the five constraints from the file above. The asterisks (*) indicate that the variable affects the feasibility
53   	 * of the constraint. In the special case of a linear optimization problem, the asterisks correspond to the
54   	 * nonzero entries of the constraint matrix.
55   	 *
56   	 *                     x1  x2  x3  x4  x5  x6  x7
57   	 *            consA     *       *                 \ BLOCK 0
58   	 *            consB     *   *                     /
59   	 *            consC                 *   *         \ BLOCK 1
60   	 *            consD                     *   *     /
61   	 *     linkingconss     *   *   *   *   *   *   * > MASTERCONSS
62   	 *
63   	 * The nonzero pattern has been chosen in a way that after the removal of the last constraint 'linkingcons', the remaining problem
64   	 * consists of two independent parts, namely the blocks '0' and '1'.
65   	 *
66   	 * The corresponding variable labels are inferred from the constraint labels. A variable is assigned the label
67   	 *
68   	 * - of its unique block, if it only occurs in exactly 1 named block, and probably in MASTERCONSS.
69   	 * - the special label of a linking variable if it occurs only in the master constraints or in 2 or even more named blocks.
70   	 *
71   	 * @note A trivial decomposition is to assign all constraints of a problem to the MASTERCONSS.
72   	 *
73   	 * @note The number of blocks is the number of named blocks: a trivial decomposition should have 0 blocks
74   	 */
75   	
76   	/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
77   	
78   	#ifndef __SCIP_READER_DEC_H__
79   	#define __SCIP_READER_DEC_H__
80   	
81   	#include "scip/def.h"
82   	#include "scip/type_retcode.h"
83   	#include "scip/type_scip.h"
84   	
85   	#ifdef __cplusplus
86   	extern "C" {
87   	#endif
88   	
89   	/** includes the decomposition file reader into SCIP
90   	 *
91   	 *  @ingroup FileReaderIncludes
92   	 */
93   	SCIP_EXPORT
94   	SCIP_RETCODE SCIPincludeReaderDec(
95   	   SCIP*                 scip                /**< SCIP data structure */
96   	   );
97   	
98   	#ifdef __cplusplus
99   	}
100  	#endif
101  	
102  	#endif
103