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_randrounding.h 26 * @ingroup PRIMALHEURISTICS 27 * @brief randomized LP rounding heuristic which also generates conflicts via an auxiliary probing tree 28 * @author Gregor Hendel 29 * 30 * Randomized LP rounding uses a random variable from a uniform distribution 31 * over [0,1] to determine whether the fractional LP value x should be rounded 32 * up with probability x - floor(x) or down with probability ceil(x) - x. 33 * 34 * This implementation uses domain propagation techniques to tighten the variable domains after every 35 * rounding step. 36 * 37 * @see: The most relevant publication is Raghavan & Thompson, 38 * "Randomized rounding: A technique for provably good algorithms and algorithmic proofs", 39 * Combinatorica 7 (4): 365–374 40 * 1987 41 */ 42 43 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 44 45 #ifndef __SCIP_HEUR_RANDROUNDING_H__ 46 #define __SCIP_HEUR_RANDROUNDING_H__ 47 48 #include "scip/def.h" 49 #include "scip/type_retcode.h" 50 #include "scip/type_scip.h" 51 52 #ifdef __cplusplus 53 extern "C" { 54 #endif 55 56 /** creates the rand rounding heuristic and includes it in SCIP 57 * 58 * @ingroup PrimalHeuristicIncludes 59 */ 60 SCIP_EXPORT 61 SCIP_RETCODE SCIPincludeHeurRandrounding( 62 SCIP* scip /**< SCIP data structure */ 63 ); 64 65 #ifdef __cplusplus 66 } 67 #endif 68 69 #endif 70