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 cons_sos1.h 26 * @ingroup CONSHDLRS 27 * @brief constraint handler for SOS type 1 constraints 28 * @author Tobias Fischer 29 * @author Marc Pfetsch 30 * 31 */ 32 33 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 34 35 #ifndef __SCIP_CONS_SOS1_H__ 36 #define __SCIP_CONS_SOS1_H__ 37 38 39 #include "scip/def.h" 40 #include "scip/type_cons.h" 41 #include "scip/type_misc.h" 42 #include "scip/type_retcode.h" 43 #include "scip/type_scip.h" 44 #include "scip/type_sol.h" 45 #include "scip/type_var.h" 46 47 #ifdef __cplusplus 48 extern "C" { 49 #endif 50 51 /** creates the handler for SOS1 constraints and includes it in SCIP 52 * 53 * @ingroup ConshdlrIncludes 54 * */ 55 SCIP_EXPORT 56 SCIP_RETCODE SCIPincludeConshdlrSOS1( 57 SCIP* scip /**< SCIP data structure */ 58 ); 59 60 /**@addtogroup CONSHDLRS 61 * 62 * @{ 63 * 64 * @name Specially Ordered Set (SOS) Type 1 Constraints 65 * 66 * @{ 67 * 68 * A specially ordered set of type 1 (SOS1) is a sequence of variables such that at most one 69 * variable is nonzero. The special case of two variables arises, for instance, from equilibrium or 70 * complementary conditions like \f$x \cdot y = 0\f$. Note that it is in principle allowed that a 71 * variable appears twice, but it then can be fixed to 0. 72 */ 73 74 /** creates and captures an SOS1 constraint 75 * 76 * We set the constraint to not be modifable. If the weights are non 77 * NULL, the variables are ordered according to these weights (in 78 * ascending order). 79 * 80 * @note The constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons(). 81 */ 82 SCIP_EXPORT 83 SCIP_RETCODE SCIPcreateConsSOS1( 84 SCIP* scip, /**< SCIP data structure */ 85 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 86 const char* name, /**< name of constraint */ 87 int nvars, /**< number of variables in the constraint */ 88 SCIP_VAR** vars, /**< array with variables of constraint entries */ 89 SCIP_Real* weights, /**< weights determining the variable order, or NULL if natural order should be used */ 90 SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP? 91 * Usually set to TRUE. Set to FALSE for 'lazy constraints'. */ 92 SCIP_Bool separate, /**< should the constraint be separated during LP processing? 93 * Usually set to TRUE. */ 94 SCIP_Bool enforce, /**< should the constraint be enforced during node processing? 95 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 96 SCIP_Bool check, /**< should the constraint be checked for feasibility? 97 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 98 SCIP_Bool propagate, /**< should the constraint be propagated during node processing? 99 * Usually set to TRUE. */ 100 SCIP_Bool local, /**< is constraint only valid locally? 101 * Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints. */ 102 SCIP_Bool dynamic, /**< is constraint subject to aging? 103 * Usually set to FALSE. Set to TRUE for own cuts which 104 * are separated as constraints. */ 105 SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup? 106 * Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'. */ 107 SCIP_Bool stickingatnode /**< should the constraint always be kept at the node where it was added, even 108 * if it may be moved to a more global node? 109 * Usually set to FALSE. Set to TRUE to for constraints that represent node data. */ 110 ); 111 112 /** creates and captures an SOS1 constraint 113 * in its most basic variant, i. e., with all constraint flags set to their default values, which can be set 114 * afterwards using SCIPsetConsFLAGNAME() in scip.h 115 * 116 * @see SCIPcreateConsSOS1() for the default constraint flag configuration 117 * 118 * @warning Do NOT set the constraint to be modifiable manually, because this might lead 119 * to wrong results as the variable array will not be resorted 120 * 121 * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() 122 */ 123 SCIP_EXPORT 124 SCIP_RETCODE SCIPcreateConsBasicSOS1( 125 SCIP* scip, /**< SCIP data structure */ 126 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 127 const char* name, /**< name of constraint */ 128 int nvars, /**< number of variables in the constraint */ 129 SCIP_VAR** vars, /**< array with variables of constraint entries */ 130 SCIP_Real* weights /**< weights determining the variable order, or NULL if natural order should be used */ 131 ); 132 133 /** adds variable to SOS1 constraint, the position is determined by the given weight */ 134 SCIP_EXPORT 135 SCIP_RETCODE SCIPaddVarSOS1( 136 SCIP* scip, /**< SCIP data structure */ 137 SCIP_CONS* cons, /**< constraint */ 138 SCIP_VAR* var, /**< variable to add to the constraint */ 139 SCIP_Real weight /**< weight determining position of variable */ 140 ); 141 142 /** appends variable to SOS1 constraint */ 143 SCIP_EXPORT 144 SCIP_RETCODE SCIPappendVarSOS1( 145 SCIP* scip, /**< SCIP data structure */ 146 SCIP_CONS* cons, /**< constraint */ 147 SCIP_VAR* var /**< variable to add to the constraint */ 148 ); 149 150 /** gets number of variables in SOS1 constraint */ 151 SCIP_EXPORT 152 int SCIPgetNVarsSOS1( 153 SCIP* scip, /**< SCIP data structure */ 154 SCIP_CONS* cons /**< constraint */ 155 ); 156 157 /** gets array of variables in SOS1 constraint */ 158 SCIP_EXPORT 159 SCIP_VAR** SCIPgetVarsSOS1( 160 SCIP* scip, /**< SCIP data structure */ 161 SCIP_CONS* cons /**< constraint data */ 162 ); 163 164 /** gets array of weights in SOS1 constraint (or NULL if not existent) */ 165 SCIP_EXPORT 166 SCIP_Real* SCIPgetWeightsSOS1( 167 SCIP* scip, /**< SCIP data structure */ 168 SCIP_CONS* cons /**< constraint data */ 169 ); 170 171 /** gets conflict graph of SOS1 constraints (or NULL if not existent) 172 * 173 * @note The conflict graph is globally valid; local changes are not taken into account. 174 */ 175 SCIP_EXPORT 176 SCIP_DIGRAPH* SCIPgetConflictgraphSOS1( 177 SCIP_CONSHDLR* conshdlr /**< SOS1 constraint handler */ 178 ); 179 180 /** gets number of problem variables that are part of the SOS1 conflict graph */ 181 SCIP_EXPORT 182 int SCIPgetNSOS1Vars( 183 SCIP_CONSHDLR* conshdlr /**< SOS1 constraint handler */ 184 ); 185 186 /** returns whether variable is part of the SOS1 conflict graph */ 187 SCIP_EXPORT 188 SCIP_Bool SCIPvarIsSOS1( 189 SCIP_CONSHDLR* conshdlr, /**< SOS1 constraint handler */ 190 SCIP_VAR* var /**< variable */ 191 ); 192 193 /** returns node of variable in the conflict graph or -1 if variable is not part of the SOS1 conflict graph */ 194 SCIP_EXPORT 195 int SCIPvarGetNodeSOS1( 196 SCIP_CONSHDLR* conshdlr, /**< SOS1 constraint handler */ 197 SCIP_VAR* var /**< variable */ 198 ); 199 200 /** returns variable that belongs to a given node from the conflict graph */ 201 SCIP_EXPORT 202 SCIP_VAR* SCIPnodeGetVarSOS1( 203 SCIP_DIGRAPH* conflictgraph, /**< conflict graph */ 204 int node /**< node from the conflict graph */ 205 ); 206 207 /** based on solution values of the variables, fixes variables to zero to turn all SOS1 constraints feasible */ 208 SCIP_EXPORT 209 SCIP_RETCODE SCIPmakeSOS1sFeasible( 210 SCIP* scip, /**< SCIP pointer */ 211 SCIP_CONSHDLR* conshdlr, /**< SOS1 constraint handler */ 212 SCIP_SOL* sol, /**< solution */ 213 SCIP_Bool* changed, /**< pointer to store whether the solution has been changed */ 214 SCIP_Bool* success /**< pointer to store whether SOS1 constraints have been turned feasible and 215 * solution was good enough */ 216 ); 217 218 /** @} */ 219 220 /** @} */ 221 222 #ifdef __cplusplus 223 } 224 #endif 225 226 #endif 227