scip_pricer.c

Go to the documentation of this file.

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*                                                                           */
/*                  This file is part of the program and library             */
/*         SCIP --- Solving Constraint Integer Programs                      */
/*                                                                           */
/*  Copyright (c) 2002-2024 Zuse Institute Berlin (ZIB)                      */
/*                                                                           */
/*  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   scip_pricer.c
 * @ingroup OTHER_CFILES
 * @brief  public methods for variable pricer plugins
 * @author Tobias Achterberg
 * @author Timo Berthold
 * @author Gerald Gamrath
 * @author Leona Gottwald
 * @author Stefan Heinz
 * @author Gregor Hendel
 * @author Thorsten Koch
 * @author Alexander Martin
 * @author Marc Pfetsch
 * @author Michael Winkler
 * @author Kati Wolter
 *
 * @todo check all SCIP_STAGE_* switches, and include the new stages TRANSFORMED and INITSOLVE
 */

/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/

#include "scip/debug.h"
#include "scip/pricer.h"
#include "scip/pub_message.h"
#include "scip/scip_pricer.h"
#include "scip/set.h"
#include "scip/struct_mem.h"
#include "scip/struct_scip.h"
#include "scip/struct_set.h"

/** creates a variable pricer and includes it in SCIP
 *  To use the variable pricer for solving a problem, it first has to be activated with a call to SCIPactivatePricer().
 *  This should be done during the problem creation stage.
 *
 *  @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
 *          SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
 *
 *  @pre This method can be called if SCIP is in one of the following stages:
 *       - \ref SCIP_STAGE_INIT
 *       - \ref SCIP_STAGE_PROBLEM
 *
 *  @note method has all pricer callbacks as arguments and is thus changed every time a new callback is added
 *        in future releases; consider using SCIPincludePricerBasic() and setter functions
 *        if you seek for a method which is less likely to change in future releases
 */
SCIP_RETCODE SCIPincludePricer(
   SCIP*                 scip,               /**< SCIP data structure */
   const char*           name,               /**< name of variable pricer */
   const char*           desc,               /**< description of variable pricer */
   int                   priority,           /**< priority of the variable pricer */
   SCIP_Bool             delay,              /**< should the pricer be delayed until no other pricers or already existing
                                              *   problem variables with negative reduced costs are found?
                                              *   if this is set to FALSE it may happen that the pricer produces columns
                                              *   that already exist in the problem (which are also priced in by the
                                              *   default problem variable pricing in the same round) */
   SCIP_DECL_PRICERCOPY  ((*pricercopy)),    /**< copy method of variable pricer or NULL if you don't want to copy your plugin into sub-SCIPs */
   SCIP_DECL_PRICERFREE  ((*pricerfree)),    /**< destructor of variable pricer */
   SCIP_DECL_PRICERINIT  ((*pricerinit)),    /**< initialize variable pricer */
   SCIP_DECL_PRICEREXIT  ((*pricerexit)),    /**< deinitialize variable pricer */
   SCIP_DECL_PRICERINITSOL((*pricerinitsol)),/**< solving process initialization method of variable pricer */
   SCIP_DECL_PRICEREXITSOL((*pricerexitsol)),/**< solving process deinitialization method of variable pricer */
   SCIP_DECL_PRICERREDCOST((*pricerredcost)),/**< reduced cost pricing method of variable pricer for feasible LPs */
   SCIP_DECL_PRICERFARKAS((*pricerfarkas)),  /**< Farkas pricing method of variable pricer for infeasible LPs */
   SCIP_PRICERDATA*      pricerdata          /**< variable pricer data */
   )
{
   SCIP_PRICER* pricer;

   SCIP_CALL( SCIPcheckStage(scip, "SCIPincludePricer", TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE) );

   /* check whether pricer is already present */
   if( SCIPfindPricer(scip, name) != NULL )
   {
      SCIPerrorMessage("pricer <%s> already included.\n", name);
      return SCIP_INVALIDDATA;
   }

   SCIP_CALL( SCIPpricerCreate(&pricer, scip->set, scip->messagehdlr, scip->mem->setmem,
         name, desc, priority, delay,
         pricercopy,
         pricerfree, pricerinit, pricerexit, pricerinitsol, pricerexitsol, pricerredcost, pricerfarkas, pricerdata) );
   SCIP_CALL( SCIPsetIncludePricer(scip->set, pricer) );

   return SCIP_OKAY;
}

/** creates a variable pricer and includes it in SCIP with all non-fundamental callbacks set to NULL;
 *  if needed, these can be added afterwards via setter functions SCIPsetPricerCopy(), SCIPsetPricerFree(),
 *  SCIPsetPricerInity(), SCIPsetPricerExit(), SCIPsetPricerInitsol(), SCIPsetPricerExitsol(),
 *  SCIPsetPricerFarkas();
 *
 *  To use the variable pricer for solving a problem, it first has to be activated with a call to SCIPactivatePricer().
 *  This should be done during the problem creation stage.
 *
 *  @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
 *          SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
 *
 *  @pre This method can be called if SCIP is in one of the following stages:
 *       - \ref SCIP_STAGE_INIT
 *       - \ref SCIP_STAGE_PROBLEM
 *
 *  @note if you want to set all callbacks with a single method call, consider using SCIPincludePricer() instead
 */
SCIP_RETCODE SCIPincludePricerBasic(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_PRICER**         pricerptr,          /**< reference to a pricer, or NULL */
   const char*           name,               /**< name of variable pricer */
   const char*           desc,               /**< description of variable pricer */
   int                   priority,           /**< priority of the variable pricer */
   SCIP_Bool             delay,              /**< should the pricer be delayed until no other pricers or already existing
                                              *   problem variables with negative reduced costs are found?
                                              *   if this is set to FALSE it may happen that the pricer produces columns
                                              *   that already exist in the problem (which are also priced in by the
                                              *   default problem variable pricing in the same round) */
   SCIP_DECL_PRICERREDCOST((*pricerredcost)),/**< reduced cost pricing method of variable pricer for feasible LPs */
   SCIP_DECL_PRICERFARKAS((*pricerfarkas)),  /**< Farkas pricing method of variable pricer for infeasible LPs */
   SCIP_PRICERDATA*      pricerdata          /**< variable pricer data */
   )
{
   SCIP_PRICER* pricer;

   SCIP_CALL( SCIPcheckStage(scip, "SCIPincludePricerBasic", TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE) );

   /* check whether pricer is already present */
   if( SCIPfindPricer(scip, name) != NULL )
   {
      SCIPerrorMessage("pricer <%s> already included.\n", name);
      return SCIP_INVALIDDATA;
   }

   SCIP_CALL( SCIPpricerCreate(&pricer, scip->set, scip->messagehdlr, scip->mem->setmem,
         name, desc, priority, delay,
         NULL,
         NULL, NULL, NULL, NULL, NULL, pricerredcost, pricerfarkas, pricerdata) );
   SCIP_CALL( SCIPsetIncludePricer(scip->set, pricer) );

   if( pricerptr != NULL )
      *pricerptr = pricer;

   return SCIP_OKAY;
}

/** sets copy method of pricer
 *
 *  @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
 *          SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
 *
 *  @pre This method can be called if SCIP is in one of the following stages:
 *       - \ref SCIP_STAGE_INIT
 *       - \ref SCIP_STAGE_PROBLEM
 */
SCIP_RETCODE SCIPsetPricerCopy(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_PRICER*          pricer,             /**< pricer */
   SCIP_DECL_PRICERCOPY ((*pricercopy))     /**< copy method of pricer or NULL if you don't want to copy your plugin into sub-SCIPs */
   )
{
   SCIP_CALL( SCIPcheckStage(scip, "SCIPsetPricerCopy", TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE) );

   assert(pricer != NULL);

   SCIPpricerSetCopy(pricer, pricercopy);

   return SCIP_OKAY;
}

/** sets destructor method of pricer
 *
 *  @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
 *          SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
 *
 *  @pre This method can be called if SCIP is in one of the following stages:
 *       - \ref SCIP_STAGE_INIT
 *       - \ref SCIP_STAGE_PROBLEM
 */
SCIP_RETCODE SCIPsetPricerFree(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_PRICER*          pricer,             /**< pricer */
   SCIP_DECL_PRICERFREE ((*pricerfree))      /**< destructor of pricer */
   )
{
   SCIP_CALL( SCIPcheckStage(scip, "SCIPsetPricerFree", TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE) );

   assert(pricer != NULL);

   SCIPpricerSetFree(pricer, pricerfree);

   return SCIP_OKAY;
}

/** sets initialization method of pricer
 *
 *  @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
 *          SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
 *
 *  @pre This method can be called if SCIP is in one of the following stages:
 *       - \ref SCIP_STAGE_INIT
 *       - \ref SCIP_STAGE_PROBLEM
 */
SCIP_RETCODE SCIPsetPricerInit(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_PRICER*          pricer,             /**< pricer */
   SCIP_DECL_PRICERINIT  ((*pricerinit))     /**< initialize pricer */
   )
{
   SCIP_CALL( SCIPcheckStage(scip, "SCIPsetPricerInit", TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE) );

   assert(pricer != NULL);

   SCIPpricerSetInit(pricer, pricerinit);

   return SCIP_OKAY;
}

/** sets deinitialization method of pricer
 *
 *  @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
 *          SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
 *
 *  @pre This method can be called if SCIP is in one of the following stages:
 *       - \ref SCIP_STAGE_INIT
 *       - \ref SCIP_STAGE_PROBLEM
 */
SCIP_RETCODE SCIPsetPricerExit(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_PRICER*          pricer,             /**< pricer */
   SCIP_DECL_PRICEREXIT  ((*pricerexit))     /**< deinitialize pricer */
   )
{
   SCIP_CALL( SCIPcheckStage(scip, "SCIPsetPricerExit", TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE) );

   assert(pricer != NULL);

   SCIPpricerSetExit(pricer, pricerexit);

   return SCIP_OKAY;
}

/** sets solving process initialization method of pricer
 *
 *  @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
 *          SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
 *
 *  @pre This method can be called if SCIP is in one of the following stages:
 *       - \ref SCIP_STAGE_INIT
 *       - \ref SCIP_STAGE_PROBLEM
 */
SCIP_RETCODE SCIPsetPricerInitsol(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_PRICER*          pricer,             /**< pricer */
   SCIP_DECL_PRICERINITSOL ((*pricerinitsol))/**< solving process initialization method of pricer */
   )
{
   SCIP_CALL( SCIPcheckStage(scip, "SCIPsetPricerInitsol", TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE) );

   assert(pricer != NULL);

   SCIPpricerSetInitsol(pricer, pricerinitsol);

   return SCIP_OKAY;
}

/** sets solving process deinitialization method of pricer
 *
 *  @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
 *          SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
 *
 *  @pre This method can be called if SCIP is in one of the following stages:
 *       - \ref SCIP_STAGE_INIT
 *       - \ref SCIP_STAGE_PROBLEM
 */
SCIP_RETCODE SCIPsetPricerExitsol(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_PRICER*          pricer,             /**< pricer */
   SCIP_DECL_PRICEREXITSOL((*pricerexitsol)) /**< solving process deinitialization method of pricer */
   )
{
   SCIP_CALL( SCIPcheckStage(scip, "SCIPsetPricerExitsol", TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE) );

   assert(pricer != NULL);

   SCIPpricerSetExitsol(pricer, pricerexitsol);

   return SCIP_OKAY;
}

/** returns the variable pricer of the given name, or NULL if not existing */
SCIP_PRICER* SCIPfindPricer(
   SCIP*                 scip,               /**< SCIP data structure */
   const char*           name                /**< name of variable pricer */
   )
{
   assert(scip != NULL);
   assert(scip->set != NULL);
   assert(name != NULL);

   return SCIPsetFindPricer(scip->set, name);
}

/** returns the array of currently available variable pricers; active pricers are in the first slots of the array */
SCIP_PRICER** SCIPgetPricers(
   SCIP*                 scip                /**< SCIP data structure */
   )
{
   assert(scip != NULL);
   assert(scip->set != NULL);

   SCIPsetSortPricers(scip->set);

   return scip->set->pricers;
}

/** returns the number of currently available variable pricers */
int SCIPgetNPricers(
   SCIP*                 scip                /**< SCIP data structure */
   )
{
   assert(scip != NULL);
   assert(scip->set != NULL);

   return scip->set->npricers;
}

/** returns the number of currently active variable pricers, that are used in the LP solving loop */
int SCIPgetNActivePricers(
   SCIP*                 scip                /**< SCIP data structure */
   )
{
   assert(scip != NULL);
   assert(scip->set != NULL);

   return scip->set->nactivepricers;
}

/** sets the priority priority of a variable pricer */
SCIP_RETCODE SCIPsetPricerPriority(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_PRICER*          pricer,             /**< variable pricer */
   int                   priority            /**< new priority of the variable pricer */
   )
{
   assert(scip != NULL);
   assert(scip->set != NULL);

   SCIPpricerSetPriority(pricer, scip->set, priority);

   return SCIP_OKAY;
}

/** activates pricer to be used for the current problem
 *  This method should be called during the problem creation stage for all pricers that are necessary to solve
 *  the problem model.
 *  The pricers are automatically deactivated when the problem is freed.
 *
 *  @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
 *          SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
 *
 *  @pre This method can be called if SCIP is in one of the following stages:
 *       - \ref SCIP_STAGE_PROBLEM
 */
SCIP_RETCODE SCIPactivatePricer(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_PRICER*          pricer              /**< variable pricer */
   )
{
   SCIP_CALL( SCIPcheckStage(scip, "SCIPactivatePricer", FALSE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE) );

   SCIP_CALL( SCIPpricerActivate(pricer, scip->set) );

   return SCIP_OKAY;
}

/** deactivates pricer
 *
 *  @return \ref SCIP_OKAY is returned if everything worked. Otherwise a suitable error code is passed. See \ref
 *          SCIP_Retcode "SCIP_RETCODE" for a complete list of error codes.
 *
 *  @pre This method can be called if SCIP is in one of the following stages:
 *       - \ref SCIP_STAGE_PROBLEM
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_EXITSOLVE
 */
SCIP_RETCODE SCIPdeactivatePricer(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_PRICER*          pricer              /**< variable pricer */
   )
{
   SCIP_CALL( SCIPcheckStage(scip, "SCIPdeactivatePricer", FALSE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE, FALSE, TRUE, FALSE, FALSE) );

   SCIP_CALL( SCIPpricerDeactivate(pricer, scip->set) );

   return SCIP_OKAY;
}