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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* */
/* 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