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_dualval.h 26 * @ingroup PRIMALHEURISTICS 27 * @brief primal heuristic that uses dualvalues for successive switching variable values 28 * @author Tobias Buchwald 29 * 30 * This heuristic tries to find solutions by taking the LP or NLP, rounding solution values, fixing the variables to the 31 * rounded values and then changing some of the values.To determine which variable is changed we give each variable a 32 * ranking dependent on its dualvalue. We work with a transformed problem that is always feasible and has objective = 0 33 * iff the original problem is also feasible. Thus we cannot expect to find really good solutions. 34 */ 35 36 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 37 38 #ifndef __SCIP_HEUR_DUALVAL_H__ 39 #define __SCIP_HEUR_DUALVAL_H__ 40 41 #include "scip/def.h" 42 #include "scip/type_heur.h" 43 #include "scip/type_result.h" 44 #include "scip/type_retcode.h" 45 #include "scip/type_scip.h" 46 #include "scip/type_sol.h" 47 48 #ifdef __cplusplus 49 extern "C" { 50 #endif 51 52 /** creates the dualVal primal heuristic and includes it in SCIP 53 * 54 * @ingroup PrimalHeuristicIncludes 55 */ 56 SCIP_EXPORT 57 SCIP_RETCODE SCIPincludeHeurDualval( 58 SCIP* scip /**< SCIP data structure */ 59 ); 60 61 /**@addtogroup PRIMALHEURISTICS 62 * 63 * @{ 64 */ 65 66 /** main procedure of the dualval heuristic */ 67 SCIP_EXPORT 68 SCIP_RETCODE SCIPapplyHeurDualval( 69 SCIP* scip, /**< original SCIP data structure */ 70 SCIP_HEUR* heur, /**< heuristic data structure */ 71 SCIP_RESULT* result, /**< pointer to store result of: did not run, solution found, no solution 72 * found, or fixing is infeasible (cutoff) */ 73 SCIP_SOL* refpoint /**< point to take fixation of discrete variables from; if NULL, then LP 74 * solution is used */ 75 ); 76 77 /** @} */ 78 79 #ifdef __cplusplus 80 } 81 #endif 82 83 #endif 84