1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ 2 /* */ 3 /* This file is part of the program and library */ 4 /* SCIP --- Solving Constraint Integer Programs */ 5 /* */ 6 /* Copyright (C) 2002-2021 Konrad-Zuse-Zentrum */ 7 /* fuer Informationstechnik Berlin */ 8 /* */ 9 /* SCIP is distributed under the terms of the ZIB Academic License. */ 10 /* */ 11 /* You should have received a copy of the ZIB Academic License */ 12 /* along with SCIP; see the file COPYING. If not visit scipopt.org. */ 13 /* */ 14 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ 15 16 /**@file cons_sos1.h 17 * @ingroup CONSHDLRS 18 * @brief constraint handler for SOS type 1 constraints 19 * @author Tobias Fischer 20 * @author Marc Pfetsch 21 * 22 */ 23 24 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 25 26 #ifndef __SCIP_CONS_SOS1_H__ 27 #define __SCIP_CONS_SOS1_H__ 28 29 30 #include "scip/def.h" 31 #include "scip/type_cons.h" 32 #include "scip/type_misc.h" 33 #include "scip/type_retcode.h" 34 #include "scip/type_scip.h" 35 #include "scip/type_sol.h" 36 #include "scip/type_var.h" 37 38 #ifdef __cplusplus 39 extern "C" { 40 #endif 41 42 /** creates the handler for SOS1 constraints and includes it in SCIP 43 * 44 * @ingroup ConshdlrIncludes 45 * */ 46 SCIP_EXPORT 47 SCIP_RETCODE SCIPincludeConshdlrSOS1( 48 SCIP* scip /**< SCIP data structure */ 49 ); 50 51 /**@addtogroup CONSHDLRS 52 * 53 * @{ 54 * 55 * @name Specially Ordered Set (SOS) Type 1 Constraints 56 * 57 * @{ 58 * 59 * A specially ordered set of type 1 (SOS1) is a sequence of variables such that at most one 60 * variable is nonzero. The special case of two variables arises, for instance, from equilibrium or 61 * complementary conditions like \f$x \cdot y = 0\f$. Note that it is in principle allowed that a 62 * variable appears twice, but it then can be fixed to 0. 63 */ 64 65 /** creates and captures an SOS1 constraint 66 * 67 * We set the constraint to not be modifable. If the weights are non 68 * NULL, the variables are ordered according to these weights (in 69 * ascending order). 70 * 71 * @note The constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons(). 72 */ 73 SCIP_EXPORT 74 SCIP_RETCODE SCIPcreateConsSOS1( 75 SCIP* scip, /**< SCIP data structure */ 76 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 77 const char* name, /**< name of constraint */ 78 int nvars, /**< number of variables in the constraint */ 79 SCIP_VAR** vars, /**< array with variables of constraint entries */ 80 SCIP_Real* weights, /**< weights determining the variable order, or NULL if natural order should be used */ 81 SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP? 82 * Usually set to TRUE. Set to FALSE for 'lazy constraints'. */ 83 SCIP_Bool separate, /**< should the constraint be separated during LP processing? 84 * Usually set to TRUE. */ 85 SCIP_Bool enforce, /**< should the constraint be enforced during node processing? 86 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 87 SCIP_Bool check, /**< should the constraint be checked for feasibility? 88 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 89 SCIP_Bool propagate, /**< should the constraint be propagated during node processing? 90 * Usually set to TRUE. */ 91 SCIP_Bool local, /**< is constraint only valid locally? 92 * Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints. */ 93 SCIP_Bool dynamic, /**< is constraint subject to aging? 94 * Usually set to FALSE. Set to TRUE for own cuts which 95 * are separated as constraints. */ 96 SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup? 97 * Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'. */ 98 SCIP_Bool stickingatnode /**< should the constraint always be kept at the node where it was added, even 99 * if it may be moved to a more global node? 100 * Usually set to FALSE. Set to TRUE to for constraints that represent node data. */ 101 ); 102 103 /** creates and captures an SOS1 constraint 104 * in its most basic variant, i. e., with all constraint flags set to their default values, which can be set 105 * afterwards using SCIPsetConsFLAGNAME() in scip.h 106 * 107 * @see SCIPcreateConsSOS1() for the default constraint flag configuration 108 * 109 * @warning Do NOT set the constraint to be modifiable manually, because this might lead 110 * to wrong results as the variable array will not be resorted 111 * 112 * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() 113 */ 114 SCIP_EXPORT 115 SCIP_RETCODE SCIPcreateConsBasicSOS1( 116 SCIP* scip, /**< SCIP data structure */ 117 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 118 const char* name, /**< name of constraint */ 119 int nvars, /**< number of variables in the constraint */ 120 SCIP_VAR** vars, /**< array with variables of constraint entries */ 121 SCIP_Real* weights /**< weights determining the variable order, or NULL if natural order should be used */ 122 ); 123 124 /** adds variable to SOS1 constraint, the position is determined by the given weight */ 125 SCIP_EXPORT 126 SCIP_RETCODE SCIPaddVarSOS1( 127 SCIP* scip, /**< SCIP data structure */ 128 SCIP_CONS* cons, /**< constraint */ 129 SCIP_VAR* var, /**< variable to add to the constraint */ 130 SCIP_Real weight /**< weight determining position of variable */ 131 ); 132 133 /** appends variable to SOS1 constraint */ 134 SCIP_EXPORT 135 SCIP_RETCODE SCIPappendVarSOS1( 136 SCIP* scip, /**< SCIP data structure */ 137 SCIP_CONS* cons, /**< constraint */ 138 SCIP_VAR* var /**< variable to add to the constraint */ 139 ); 140 141 /** gets number of variables in SOS1 constraint */ 142 SCIP_EXPORT 143 int SCIPgetNVarsSOS1( 144 SCIP* scip, /**< SCIP data structure */ 145 SCIP_CONS* cons /**< constraint */ 146 ); 147 148 /** gets array of variables in SOS1 constraint */ 149 SCIP_EXPORT 150 SCIP_VAR** SCIPgetVarsSOS1( 151 SCIP* scip, /**< SCIP data structure */ 152 SCIP_CONS* cons /**< constraint data */ 153 ); 154 155 /** gets array of weights in SOS1 constraint (or NULL if not existent) */ 156 SCIP_EXPORT 157 SCIP_Real* SCIPgetWeightsSOS1( 158 SCIP* scip, /**< SCIP data structure */ 159 SCIP_CONS* cons /**< constraint data */ 160 ); 161 162 /** gets conflict graph of SOS1 constraints (or NULL if not existent) 163 * 164 * @note The conflict graph is globally valid; local changes are not taken into account. 165 */ 166 SCIP_EXPORT 167 SCIP_DIGRAPH* SCIPgetConflictgraphSOS1( 168 SCIP_CONSHDLR* conshdlr /**< SOS1 constraint handler */ 169 ); 170 171 /** gets number of problem variables that are part of the SOS1 conflict graph */ 172 SCIP_EXPORT 173 int SCIPgetNSOS1Vars( 174 SCIP_CONSHDLR* conshdlr /**< SOS1 constraint handler */ 175 ); 176 177 /** returns whether variable is part of the SOS1 conflict graph */ 178 SCIP_EXPORT 179 SCIP_Bool SCIPvarIsSOS1( 180 SCIP_CONSHDLR* conshdlr, /**< SOS1 constraint handler */ 181 SCIP_VAR* var /**< variable */ 182 ); 183 184 /** returns node of variable in the conflict graph or -1 if variable is not part of the SOS1 conflict graph */ 185 SCIP_EXPORT 186 int SCIPvarGetNodeSOS1( 187 SCIP_CONSHDLR* conshdlr, /**< SOS1 constraint handler */ 188 SCIP_VAR* var /**< variable */ 189 ); 190 191 /** returns variable that belongs to a given node from the conflict graph */ 192 SCIP_EXPORT 193 SCIP_VAR* SCIPnodeGetVarSOS1( 194 SCIP_DIGRAPH* conflictgraph, /**< conflict graph */ 195 int node /**< node from the conflict graph */ 196 ); 197 198 /** based on solution values of the variables, fixes variables to zero to turn all SOS1 constraints feasible */ 199 SCIP_EXPORT 200 SCIP_RETCODE SCIPmakeSOS1sFeasible( 201 SCIP* scip, /**< SCIP pointer */ 202 SCIP_CONSHDLR* conshdlr, /**< SOS1 constraint handler */ 203 SCIP_SOL* sol, /**< solution */ 204 SCIP_Bool* changed, /**< pointer to store whether the solution has been changed */ 205 SCIP_Bool* success /**< pointer to store whether SOS1 constraints have been turned feasible and 206 * solution was good enough */ 207 ); 208 209 /** @} */ 210 211 /** @} */ 212 213 #ifdef __cplusplus 214 } 215 #endif 216 217 #endif 218