Scippy

SCIP

Solving Constraint Integer Programs

reader_dec.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 2002-2022 Zuse Institute Berlin */
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, */
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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
95  SCIP* scip /**< SCIP data structure */
96  );
97 
98 #ifdef __cplusplus
99 }
100 #endif
101 
102 #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 SCIPincludeReaderDec(SCIP *scip)
Definition: reader_dec.c:382
common defines and data types used in all packages of SCIP