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_rounding.h 26 * @ingroup PRIMALHEURISTICS 27 * @brief LP rounding heuristic that tries to recover from intermediate infeasibilities 28 * @author Tobias Achterberg 29 * 30 * Rounding heuristic that starts from an LP-feasible point and reduces the number of fractional variables by one in 31 * each step. As long as no LP row is violated, the algorithm iterates over the fractional variables and applies a 32 * rounding into the direction of fewer locks, updating the activities of the LP rows after each step. If there is a 33 * violated LP row, the heuristic will try to find a fractional variable that can be rounded in a direction such that 34 * the violation of the constraint is decreased, using the number of up- and down-locks as a tie breaker. If no 35 * rounding can decrease the violation of the constraint, the procedure is aborted. 36 */ 37 38 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 39 40 #ifndef __SCIP_HEUR_ROUNDING_H__ 41 #define __SCIP_HEUR_ROUNDING_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 rounding heuristic with infeasibility recovering and includes it in SCIP 52 * 53 * @ingroup PrimalHeuristicIncludes 54 */ 55 SCIP_EXPORT 56 SCIP_RETCODE SCIPincludeHeurRounding( 57 SCIP* scip /**< SCIP data structure */ 58 ); 59 60 #ifdef __cplusplus 61 } 62 #endif 63 64 #endif 65