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_linking.h 26 * @ingroup CONSHDLRS 27 * @brief constraint handler for linking binary variables to a linking (continuous or integer) variable 28 * @author Stefan Heinz 29 * @author Jens Schulz 30 * 31 */ 32 33 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ 34 35 #ifndef __SCIP_CONS_LINKING_H__ 36 #define __SCIP_CONS_LINKING_H__ 37 38 39 #include "scip/def.h" 40 #include "scip/type_cons.h" 41 #include "scip/type_retcode.h" 42 #include "scip/type_scip.h" 43 #include "scip/type_var.h" 44 45 #ifdef __cplusplus 46 extern "C" { 47 #endif 48 49 /** creates the handler for linking constraints and includes it in SCIP 50 * 51 * @ingroup ConshdlrIncludes 52 * */ 53 SCIP_EXPORT 54 SCIP_RETCODE SCIPincludeConshdlrLinking( 55 SCIP* scip /**< SCIP data structure */ 56 ); 57 58 /**@addtogroup CONSHDLRS 59 * 60 * @{ 61 * 62 * @name Linking Constraints 63 * 64 * @{ 65 * 66 * The constraints handler stores linking constraints between a linking variable (continuous or integer) and an array of binary variables. Such 67 * a linking constraint has the form: 68 * \f[ 69 * y = \sum_{i=1}^n {c_i * x_i} 70 * \f] 71 * with linking variable (continuous or integer) \f$ y \f$, binary variables \f$ x_1, \dots, x_n \f$ and offset \f$b \in Q\f$, and 72 * with the additional side condition that exactly one binary variable has to be one (set partitioning condition). 73 * 74 * This constraint can be created only with the linking variable, if it is an integer variable. In this case the binary variables are only created on 75 * demand. That is, whenever someone asks for the binary variables. Therefore, such constraints can be used to get a 76 * "binary representation" of the domain of the linking variable which will be dynamically created. 77 */ 78 79 /** creates and captures a linking constraint 80 * 81 * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() 82 */ 83 SCIP_EXPORT 84 SCIP_RETCODE SCIPcreateConsLinking( 85 SCIP* scip, /**< SCIP data structure */ 86 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 87 const char* name, /**< name of constraint */ 88 SCIP_VAR* linkvar, /**< linking variable (continuous or integer) which should be linked */ 89 SCIP_VAR** binvars, /**< binary variables */ 90 SCIP_Real* vals, /**< coefficients of the binary variables */ 91 int nbinvars, /**< number of binary starting variables */ 92 SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP? 93 * Usually set to TRUE. Set to FALSE for 'lazy constraints'. */ 94 SCIP_Bool separate, /**< should the constraint be separated during LP processing? 95 * Usually set to TRUE. */ 96 SCIP_Bool enforce, /**< should the constraint be enforced during node processing? 97 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 98 SCIP_Bool check, /**< should the constraint be checked for feasibility? 99 * TRUE for model constraints, FALSE for additional, redundant constraints. */ 100 SCIP_Bool propagate, /**< should the constraint be propagated during node processing? 101 * Usually set to TRUE. */ 102 SCIP_Bool local, /**< is constraint only valid locally? 103 * Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints. */ 104 SCIP_Bool modifiable, /**< is constraint modifiable (subject to column generation)? 105 * Usually set to FALSE. In column generation applications, set to TRUE if pricing 106 * adds coefficients to this constraint. */ 107 SCIP_Bool dynamic, /**< is constraint subject to aging? 108 * Usually set to FALSE. Set to TRUE for own cuts which 109 * are separated as constraints. */ 110 SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup? 111 * Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'. */ 112 SCIP_Bool stickingatnode /**< should the constraint always be kept at the node where it was added, even 113 * if it may be moved to a more global node? 114 * Usually set to FALSE. Set to TRUE to for constraints that represent node data. */ 115 ); 116 117 /** creates and captures a linking constraint 118 * in its most basic version, i. e., all constraint flags are set to their basic value as explained for the 119 * method SCIPcreateConsLinking(); all flags can be set via SCIPsetConsFLAGNAME-methods in scip.h 120 * 121 * @see SCIPcreateConsLinking() for information about the basic constraint flag configuration 122 * 123 * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() 124 */ 125 SCIP_EXPORT 126 SCIP_RETCODE SCIPcreateConsBasicLinking( 127 SCIP* scip, /**< SCIP data structure */ 128 SCIP_CONS** cons, /**< pointer to hold the created constraint */ 129 const char* name, /**< name of constraint */ 130 SCIP_VAR* linkvar, /**< linking variable (continuous or integer) which should be linked */ 131 SCIP_VAR** binvars, /**< binary variables, or NULL */ 132 SCIP_Real* vals, /**< coefficients of the binary variables */ 133 int nbinvars /**< number of binary variables */ 134 ); 135 136 137 /** checks if for the given linking variable (continuous or integer) a linking constraint exists */ 138 SCIP_EXPORT 139 SCIP_Bool SCIPexistsConsLinking( 140 SCIP* scip, /**< SCIP data structure */ 141 SCIP_VAR* linkvar /**< linking variable (continuous or integer) which should be linked */ 142 ); 143 144 /** returns the linking constraint belonging the given linking variable (continuous or integer) or NULL if it does not exist yet */ 145 SCIP_EXPORT 146 SCIP_CONS* SCIPgetConsLinking( 147 SCIP* scip, /**< SCIP data structure */ 148 SCIP_VAR* linkvar /**< linking variable (continuous or integer) which should be linked */ 149 ); 150 151 /** returns the linking variable (continuous or integer) of the linking constraint */ 152 SCIP_EXPORT 153 SCIP_VAR* SCIPgetLinkvarLinking( 154 SCIP* scip, /**< SCIP data structure */ 155 SCIP_CONS* cons /**< linking constraint */ 156 ); 157 158 /** returns the binary variables of the linking constraint */ 159 SCIP_EXPORT 160 SCIP_RETCODE SCIPgetBinvarsLinking( 161 SCIP* scip, /**< SCIP data structure */ 162 SCIP_CONS* cons, /**< linking constraint */ 163 SCIP_VAR*** binvars, /**< pointer to store the binary variables array pointer */ 164 int* nbinvars /**< pointer to store the number of returned binary variables */ 165 ); 166 167 /** returns the number of binary variables of the linking constraint */ 168 SCIP_EXPORT 169 int SCIPgetNBinvarsLinking( 170 SCIP* scip, /**< SCIP data structure */ 171 SCIP_CONS* cons /**< linking constraint */ 172 ); 173 174 /** returns the coefficients of the binary variables */ 175 SCIP_EXPORT 176 SCIP_Real* SCIPgetValsLinking( 177 SCIP* scip, /**< SCIP data structure */ 178 SCIP_CONS* cons /**< linking constraint */ 179 ); 180 181 /** return all binary variable information of the linking constraint */ 182 SCIP_EXPORT 183 SCIP_RETCODE SCIPgetBinvarsDataLinking( 184 SCIP_CONS* cons, /**< linking constraint */ 185 SCIP_VAR*** binvars, /**< pointer to store binary variables, or NULL */ 186 SCIP_Real** vals, /**< pointer to store the binary coefficients, or NULL */ 187 int* nbinvars /**< pointer to store the number of binary variables, or NULL */ 188 ); 189 190 /** @} */ 191 192 /** @} */ 193 194 #ifdef __cplusplus 195 } 196 #endif 197 198 #endif 199