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