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_rens.h 26 * @ingroup PRIMALHEURISTICS 27 * @brief LNS heuristic that finds the optimal rounding to a given point 28 * @author Timo Berthold 29 * 30 * RENS is a large neighborhood search start heuristic, i.e., unlike other LNS heuristics, it does not need a known 31 * feasible solution. It solves a sub-SCIP that is created by fixing variables which take an integral value in a given 32 * LP or NLP solution. For the remaining integer variables, the bounds get tightened to the two nearest integral values. 33 */ 34 35 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 36 37 #ifndef __SCIP_HEUR_RENS_H__ 38 #define __SCIP_HEUR_RENS_H__ 39 40 #include "scip/def.h" 41 #include "scip/type_heur.h" 42 #include "scip/type_result.h" 43 #include "scip/type_retcode.h" 44 #include "scip/type_scip.h" 45 46 #ifdef __cplusplus 47 extern "C" { 48 #endif 49 50 /** creates RENS primal heuristic and includes it in SCIP 51 * 52 * @ingroup PrimalHeuristicIncludes 53 */ 54 SCIP_EXPORT 55 SCIP_RETCODE SCIPincludeHeurRens( 56 SCIP* scip /**< SCIP data structure */ 57 ); 58 59 /**@addtogroup PRIMALHEURISTICS 60 * 61 * @{ 62 */ 63 64 /** main procedure of the RNS heuristic, creates and solves a sub-SCIP */ 65 SCIP_EXPORT 66 SCIP_RETCODE SCIPapplyRens( 67 SCIP* scip, /**< original SCIP data structure */ 68 SCIP_HEUR* heur, /**< heuristic data structure */ 69 SCIP_RESULT* result, /**< result data structure */ 70 SCIP_Real minfixingrate, /**< minimum percentage of integer variables that have to be fixed */ 71 SCIP_Real minimprove, /**< factor by which RENS should at least improve the incumbent */ 72 SCIP_Longint maxnodes, /**< maximum number of nodes for the subproblem */ 73 SCIP_Longint nstallnodes, /**< number of stalling nodes for the subproblem */ 74 char startsol, /**< solution used for fixing values ('l'p relaxation, 'n'lp relaxation) */ 75 SCIP_Bool binarybounds, /**< should general integers get binary bounds [floor(.),ceil(.)]? */ 76 SCIP_Bool uselprows /**< should subproblem be created out of the rows in the LP rows? */ 77 ); 78 79 /** @} */ 80 81 #ifdef __cplusplus 82 } 83 #endif 84 85 #endif 86