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_nlpdiving.h 26 * @ingroup PRIMALHEURISTICS 27 * @brief NLP diving heuristic that chooses fixings w.r.t. the fractionalities 28 * @author Timo Berthold 29 * @author Stefan Vigerske 30 * 31 * Diving heuristic: Iteratively fixes some fractional variables and resolves the LP and NLP relaxations, thereby simulating a 32 * depth-first-search in the tree. Double Diving chooses the variable for which the sum of the distances from the relaxations' 33 * solutions to a common integer value is minimal and rounds it to thenearest integer. 34 * One-level backtracking is applied: If the NLP gets infeasible, the last fixing is undone, and the opposite fixing is tried. 35 * If this is infeasible, too, the procedure aborts. 36 */ 37 38 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 39 40 #ifndef __SCIP_HEUR_NLPDIVING_H__ 41 #define __SCIP_HEUR_NLPDIVING_H__ 42 43 #include "scip/def.h" 44 #include "scip/type_retcode.h" 45 #include "scip/type_scip.h" 46 47 #ifdef __cplusplus 48 extern "C" { 49 #endif 50 51 /** creates the fracdiving heuristic and includes it in SCIP 52 * 53 * @ingroup PrimalHeuristicIncludes 54 */ 55 SCIP_EXPORT 56 SCIP_RETCODE SCIPincludeHeurNlpdiving( 57 SCIP* scip /**< SCIP data structure */ 58 ); 59 60 #ifdef __cplusplus 61 } 62 #endif 63 64 #endif 65