/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ /* */ /* This file is part of the program and library */ /* SCIP --- Solving Constraint Integer Programs */ /* */ /* Copyright 2002-2022 Zuse Institute Berlin */ /* */ /* Licensed under the Apache License, Version 2.0 (the "License"); */ /* you may not use this file except in compliance with the License. */ /* You may obtain a copy of the License at */ /* */ /* http://www.apache.org/licenses/LICENSE-2.0 */ /* */ /* Unless required by applicable law or agreed to in writing, software */ /* distributed under the License is distributed on an "AS IS" BASIS, */ /* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */ /* See the License for the specific language governing permissions and */ /* limitations under the License. */ /* */ /* You should have received a copy of the Apache-2.0 license */ /* along with SCIP; see the file LICENSE. If not visit scipopt.org. */ /* */ /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ /**@file cons_linking.h * @ingroup CONSHDLRS * @brief constraint handler for linking binary variables to a linking (continuous or integer) variable * @author Stefan Heinz * @author Jens Schulz * */ /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/ #ifndef __SCIP_CONS_LINKING_H__ #define __SCIP_CONS_LINKING_H__ #include "scip/def.h" #include "scip/type_cons.h" #include "scip/type_retcode.h" #include "scip/type_scip.h" #include "scip/type_var.h" #ifdef __cplusplus extern "C" { #endif /** creates the handler for linking constraints and includes it in SCIP * * @ingroup ConshdlrIncludes * */ SCIP_EXPORT SCIP_RETCODE SCIPincludeConshdlrLinking( SCIP* scip /**< SCIP data structure */ ); /**@addtogroup CONSHDLRS * * @{ * * @name Linking Constraints * * @{ * * The constraints handler stores linking constraints between a linking variable (continuous or integer) and an array of binary variables. Such * a linking constraint has the form: * \f[ * y = \sum_{i=1}^n {c_i * x_i} * \f] * 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 * with the additional side condition that exactly one binary variable has to be one (set partitioning condition). * * 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 * demand. That is, whenever someone asks for the binary variables. Therefore, such constraints can be used to get a * "binary representation" of the domain of the linking variable which will be dynamically created. */ /** creates and captures a linking constraint * * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() */ SCIP_EXPORT SCIP_RETCODE SCIPcreateConsLinking( SCIP* scip, /**< SCIP data structure */ SCIP_CONS** cons, /**< pointer to hold the created constraint */ const char* name, /**< name of constraint */ SCIP_VAR* linkvar, /**< linking variable (continuous or integer) which should be linked */ SCIP_VAR** binvars, /**< binary variables */ SCIP_Real* vals, /**< coefficients of the binary variables */ int nbinvars, /**< number of binary starting variables */ SCIP_Bool initial, /**< should the LP relaxation of constraint be in the initial LP? * Usually set to TRUE. Set to FALSE for 'lazy constraints'. */ SCIP_Bool separate, /**< should the constraint be separated during LP processing? * Usually set to TRUE. */ SCIP_Bool enforce, /**< should the constraint be enforced during node processing? * TRUE for model constraints, FALSE for additional, redundant constraints. */ SCIP_Bool check, /**< should the constraint be checked for feasibility? * TRUE for model constraints, FALSE for additional, redundant constraints. */ SCIP_Bool propagate, /**< should the constraint be propagated during node processing? * Usually set to TRUE. */ SCIP_Bool local, /**< is constraint only valid locally? * Usually set to FALSE. Has to be set to TRUE, e.g., for branching constraints. */ SCIP_Bool modifiable, /**< is constraint modifiable (subject to column generation)? * Usually set to FALSE. In column generation applications, set to TRUE if pricing * adds coefficients to this constraint. */ SCIP_Bool dynamic, /**< is constraint subject to aging? * Usually set to FALSE. Set to TRUE for own cuts which * are separated as constraints. */ SCIP_Bool removable, /**< should the relaxation be removed from the LP due to aging or cleanup? * Usually set to FALSE. Set to TRUE for 'lazy constraints' and 'user cuts'. */ SCIP_Bool stickingatnode /**< should the constraint always be kept at the node where it was added, even * if it may be moved to a more global node? * Usually set to FALSE. Set to TRUE to for constraints that represent node data. */ ); /** creates and captures a linking constraint * in its most basic version, i. e., all constraint flags are set to their basic value as explained for the * method SCIPcreateConsLinking(); all flags can be set via SCIPsetConsFLAGNAME-methods in scip.h * * @see SCIPcreateConsLinking() for information about the basic constraint flag configuration * * @note the constraint gets captured, hence at one point you have to release it using the method SCIPreleaseCons() */ SCIP_EXPORT SCIP_RETCODE SCIPcreateConsBasicLinking( SCIP* scip, /**< SCIP data structure */ SCIP_CONS** cons, /**< pointer to hold the created constraint */ const char* name, /**< name of constraint */ SCIP_VAR* linkvar, /**< linking variable (continuous or integer) which should be linked */ SCIP_VAR** binvars, /**< binary variables, or NULL */ SCIP_Real* vals, /**< coefficients of the binary variables */ int nbinvars /**< number of binary variables */ ); /** checks if for the given linking variable (continuous or integer) a linking constraint exists */ SCIP_EXPORT SCIP_Bool SCIPexistsConsLinking( SCIP* scip, /**< SCIP data structure */ SCIP_VAR* linkvar /**< linking variable (continuous or integer) which should be linked */ ); /** returns the linking constraint belonging the given linking variable (continuous or integer) or NULL if it does not exist yet */ SCIP_EXPORT SCIP_CONS* SCIPgetConsLinking( SCIP* scip, /**< SCIP data structure */ SCIP_VAR* linkvar /**< linking variable (continuous or integer) which should be linked */ ); /** returns the linking variable (continuous or integer) of the linking constraint */ SCIP_EXPORT SCIP_VAR* SCIPgetLinkvarLinking( SCIP* scip, /**< SCIP data structure */ SCIP_CONS* cons /**< linking constraint */ ); /** returns the binary variables of the linking constraint */ SCIP_EXPORT SCIP_RETCODE SCIPgetBinvarsLinking( SCIP* scip, /**< SCIP data structure */ SCIP_CONS* cons, /**< linking constraint */ SCIP_VAR*** binvars, /**< pointer to store the binary variables array pointer */ int* nbinvars /**< pointer to store the number of returned binary variables */ ); /** returns the number of binary variables of the linking constraint */ SCIP_EXPORT int SCIPgetNBinvarsLinking( SCIP* scip, /**< SCIP data structure */ SCIP_CONS* cons /**< linking constraint */ ); /** returns the coefficients of the binary variables */ SCIP_EXPORT SCIP_Real* SCIPgetValsLinking( SCIP* scip, /**< SCIP data structure */ SCIP_CONS* cons /**< linking constraint */ ); /** return all binary variable information of the linking constraint */ SCIP_EXPORT SCIP_RETCODE SCIPgetBinvarsDataLinking( SCIP_CONS* cons, /**< linking constraint */ SCIP_VAR*** binvars, /**< pointer to store binary variables, or NULL */ SCIP_Real** vals, /**< pointer to store the binary coefficients, or NULL */ int* nbinvars /**< pointer to store the number of binary variables, or NULL */ ); /** @} */ /** @} */ #ifdef __cplusplus } #endif #endif