scip_solve.h

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/*         SCIP --- Solving Constraint Integer Programs                      */
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/**@file   scip_solve.h
 * @ingroup PUBLICCOREAPI
 * @brief  public solving methods
 * @author Tobias Achterberg
 * @author Timo Berthold
 * @author Thorsten Koch
 * @author Alexander Martin
 * @author Marc Pfetsch
 * @author Kati Wolter
 * @author Gregor Hendel
 * @author Leona Gottwald
 */

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

#ifndef __SCIP_SCIP_SOLVE_H__
#define __SCIP_SCIP_SOLVE_H__


#include "scip/def.h"
#include "scip/type_retcode.h"
#include "scip/type_scip.h"
#include "scip/type_sol.h"
#include "scip/type_tree.h"
#include "scip/type_var.h"

#ifdef __cplusplus
extern "C" {
#endif

/**@addtogroup PublicSolveMethods
 *
 * @{
 */

/** initializes solving data structures and transforms problem
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_PROBLEM
 *       - \ref SCIP_STAGE_TRANSFORMED
 *       - \ref SCIP_STAGE_INITPRESOLVE
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_EXITPRESOLVE
 *       - \ref SCIP_STAGE_PRESOLVED
 *       - \ref SCIP_STAGE_INITSOLVE
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_SOLVED
 *       - \ref SCIP_STAGE_EXITSOLVE
 *       - \ref SCIP_STAGE_FREETRANS
 *       - \ref SCIP_STAGE_FREE
 *
 *  @post When calling this method in the \ref SCIP_STAGE_PROBLEM stage, the \SCIP stage is changed to \ref
 *        SCIP_STAGE_TRANSFORMED; otherwise, the stage is not changed
 *
 *  See \ref SCIP_Stage "SCIP_STAGE" for a complete list of all possible solving stages.
 */
SCIP_EXPORT
SCIP_RETCODE SCIPtransformProb(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** transforms and presolves problem
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_PROBLEM
 *       - \ref SCIP_STAGE_TRANSFORMED
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_PRESOLVED
 *       - \ref SCIP_STAGE_SOLVED
 *
 *  @post After calling this method \SCIP reaches one of the following stages:
 *        - \ref SCIP_STAGE_PRESOLVING if the presolving process was interrupted
 *        - \ref SCIP_STAGE_PRESOLVED if the presolving process was finished and did not solve the problem
 *        - \ref SCIP_STAGE_SOLVED if the problem was solved during presolving
 *
 *  See \ref SCIP_Stage "SCIP_STAGE" for a complete list of all possible solving stages.
 */
SCIP_EXPORT
SCIP_RETCODE SCIPpresolve(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** transforms, presolves, and solves problem
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_PROBLEM
 *       - \ref SCIP_STAGE_TRANSFORMED
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_PRESOLVED
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_SOLVED
 *
 *  @post After calling this method \SCIP reaches one of the following stages depending on if and when the solution
 *        process was interrupted:

 *        - \ref SCIP_STAGE_PRESOLVING if the solution process was interrupted during presolving
 *        - \ref SCIP_STAGE_SOLVING if the solution process was interrupted during the tree search
 *        - \ref SCIP_STAGE_SOLVED if the solving process was not interrupted
 *
 *  See \ref SCIP_Stage "SCIP_STAGE" for a complete list of all possible solving stages.
 */
SCIP_EXPORT
SCIP_RETCODE SCIPsolve(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** transforms, presolves, and solves problem using additional solvers which emphasize on
 *  finding solutions.
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_PROBLEM
 *       - \ref SCIP_STAGE_TRANSFORMED
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_PRESOLVED
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_SOLVED
 *
 *  @post After calling this method \SCIP reaches one of the following stages depending on if and when the solution
 *        process was interrupted:
 *        - \ref SCIP_STAGE_PRESOLVING if the solution process was interrupted during presolving
 *        - \ref SCIP_STAGE_SOLVING if the solution process was interrupted during the tree search
 *        - \ref SCIP_STAGE_SOLVED if the solving process was not interrupted
 *
 *  See \ref SCIP_Stage "SCIP_STAGE" for a complete list of all possible solving stages.
 *
 *  @deprecated Please use SCIPsolveConcurrent() instead.
 */
SCIP_EXPORT
SCIP_RETCODE SCIPsolveParallel(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** transforms, presolves, and solves problem using additional solvers which emphasize on
 *  finding solutions.
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_PROBLEM
 *       - \ref SCIP_STAGE_TRANSFORMED
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_PRESOLVED
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_SOLVED
 *
 *  @post After calling this method \SCIP reaches one of the following stages depending on if and when the solution
 *        process was interrupted:
 *        - \ref SCIP_STAGE_PRESOLVING if the solution process was interrupted during presolving
 *        - \ref SCIP_STAGE_SOLVING if the solution process was interrupted during the tree search
 *        - \ref SCIP_STAGE_SOLVED if the solving process was not interrupted
 *
 *  See \ref SCIP_Stage "SCIP_STAGE" for a complete list of all possible solving stages.
 */
SCIP_EXPORT
SCIP_RETCODE SCIPsolveConcurrent(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** frees branch and bound tree and all solution process data; statistics, presolving data and transformed problem is
 *  preserved
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_INIT
 *       - \ref SCIP_STAGE_PROBLEM
 *       - \ref SCIP_STAGE_TRANSFORMED
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_PRESOLVED
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_SOLVED
 *
 *  @post If this method is called in \SCIP stage \ref SCIP_STAGE_INIT or \ref SCIP_STAGE_PROBLEM, the stage of
 *        \SCIP is not changed; otherwise, the \SCIP stage is changed to \ref SCIP_STAGE_TRANSFORMED
 *
 *  See \ref SCIP_Stage "SCIP_STAGE" for a complete list of all possible solving stages.
 */
SCIP_EXPORT
SCIP_RETCODE SCIPfreeSolve(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_Bool             restart             /**< should certain data be preserved for improved restarting? */
   );

/** frees all solution process data including presolving and transformed problem, only original problem is kept
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_INIT
 *       - \ref SCIP_STAGE_PROBLEM
 *       - \ref SCIP_STAGE_TRANSFORMED
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_PRESOLVED
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_SOLVED
 *
 *  @post After calling this method \SCIP reaches one of the following stages:
 *        - \ref SCIP_STAGE_INIT if the method was called from \SCIP stage \ref SCIP_STAGE_INIT
 *        - \ref SCIP_STAGE_PROBLEM if the method was called from any other of the allowed stages
 *
 *  See \ref SCIP_Stage "SCIP_STAGE" for a complete list of all possible solving stages.
 */
SCIP_EXPORT
SCIP_RETCODE SCIPfreeTransform(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** informs \SCIP that the solving process should be interrupted as soon as possible (e.g., after the current node has
 *   been solved)
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_PROBLEM
 *       - \ref SCIP_STAGE_TRANSFORMING
 *       - \ref SCIP_STAGE_TRANSFORMED
 *       - \ref SCIP_STAGE_INITPRESOLVE
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_EXITPRESOLVE
 *       - \ref SCIP_STAGE_PRESOLVED
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_SOLVED
 *       - \ref SCIP_STAGE_EXITSOLVE
 *       - \ref SCIP_STAGE_FREETRANS
 *
 *  @note the \SCIP stage does not get changed
 */
SCIP_EXPORT
SCIP_RETCODE SCIPinterruptSolve(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** indicates whether \SCIP has been informed that the solving process should be interrupted as soon as possible
 *
 *  This function returns whether SCIPinterruptSolve() has been called, which is different from SCIPinterrupted(),
 *  which returns whether a SIGINT signal has been received by the SCIP signal handler.
 *
 *  @pre This method can be called if @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_PROBLEM
 *       - \ref SCIP_STAGE_TRANSFORMING
 *       - \ref SCIP_STAGE_TRANSFORMED
 *       - \ref SCIP_STAGE_INITPRESOLVE
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_EXITPRESOLVE
 *       - \ref SCIP_STAGE_PRESOLVED
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_SOLVED
 *       - \ref SCIP_STAGE_EXITSOLVE
 *       - \ref SCIP_STAGE_FREETRANS
 *
 *  @note the \SCIP stage does not get changed
 */
SCIP_EXPORT
SCIP_Bool SCIPisSolveInterrupted(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** informs SCIP that the solving process should be restarted as soon as possible (e.g., after the current node has
 *  been solved)
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_INITPRESOLVE
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_EXITPRESOLVE
 *       - \ref SCIP_STAGE_SOLVING
 *
 *  @note the \SCIP stage does not get changed
 */
SCIP_EXPORT
SCIP_RETCODE SCIPrestartSolve(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** returns whether we are in the restarting phase
 *
 *  @return TRUE, if we are in the restarting phase; FALSE, otherwise
 *
 *  @pre This method can be called if @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_INITPRESOLVE
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_EXITPRESOLVE
 *       - \ref SCIP_STAGE_PRESOLVED
 *       - \ref SCIP_STAGE_INITSOLVE
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_SOLVED
 *       - \ref SCIP_STAGE_EXITSOLVE
 *       - \ref SCIP_STAGE_FREETRANS
 */
SCIP_EXPORT
SCIP_Bool SCIPisInRestart(
   SCIP*                 scip                /**< SCIP data structure */
   );

/**@} */

/**@addtogroup PublicReoptimizationMethods
 *
 * @{
 */

/** frees branch and bound tree and all solution process data; statistics, presolving data and transformed problem is
 *  preserved
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_INIT
 *       - \ref SCIP_STAGE_PROBLEM
 *       - \ref SCIP_STAGE_TRANSFORMED
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_PRESOLVED
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_SOLVED
 *
 *  @post If this method is called in \SCIP stage \ref SCIP_STAGE_INIT or \ref SCIP_STAGE_PROBLEM, the stage of
 *        \SCIP is not changed; otherwise, the \SCIP stage is changed to \ref SCIP_STAGE_PRESOLVED.
 *
 *  See \ref SCIP_Stage "SCIP_STAGE" for a complete list of all possible solving stages.
 */
SCIP_EXPORT
SCIP_RETCODE SCIPfreeReoptSolve(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** include specific heuristics and branching rules for reoptimization
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_PROBLEM
 */
SCIP_EXPORT
SCIP_RETCODE SCIPenableReoptimization(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_Bool             enable              /**< enable reoptimization (TRUE) or disable it (FALSE) */
   );

/** returns whether reoptimization is enabled or not */
SCIP_EXPORT
SCIP_Bool SCIPisReoptEnabled(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** returns the stored solutions corresponding to a given run */
SCIP_EXPORT
SCIP_RETCODE SCIPgetReoptSolsRun(
   SCIP*                 scip,               /**< SCIP data structue */
   int                   run,                /**< number of the run */
   SCIP_SOL**            sols,               /**< array to store solutions */
   int                   allocmem,           /**< allocated size of the array */
   int*                  nsols               /**< number of solutions */
   );

/** mark all stored solutions as not updated */
SCIP_EXPORT
void SCIPresetReoptSolMarks(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** check if the reoptimization process should be restarted
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_TRANSFORMED
 *       - \ref SCIP_STAGE_SOLVING
 */
SCIP_EXPORT
SCIP_RETCODE SCIPcheckReoptRestart(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_NODE*            node,               /**< current node of the branch and bound tree (or NULL) */
   SCIP_Bool*            restart             /**< pointer to store of the reoptimitation process should be restarted */
   );

/** save bound change based on dual information in the reoptimization tree
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_SOLVING
 *       - \ref SCIP_STAGE_SOLVED
 */
SCIP_EXPORT
SCIP_RETCODE SCIPaddReoptDualBndchg(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_NODE*            node,               /**< node of the search tree */
   SCIP_VAR*             var,                /**< variable whose bound changed */
   SCIP_Real             newbound,           /**< new bound of the variable */
   SCIP_Real             oldbound            /**< old bound of the variable */
   );

/** returns the optimal solution of the last iteration or NULL of none exists */
SCIP_EXPORT
SCIP_SOL* SCIPgetReoptLastOptSol(
   SCIP*                 scip                /**< SCIP data structure */
   );

/** returns the objective coefficent of a given variable in a previous iteration
 *
 *  @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 @p scip is in one of the following stages:
 *       - \ref SCIP_STAGE_PRESOLVING
 *       - \ref SCIP_STAGE_SOLVING
 */
SCIP_EXPORT
SCIP_RETCODE SCIPgetReoptOldObjCoef(
   SCIP*                 scip,               /**< SCIP data structure */
   SCIP_VAR*             var,                /**< variable */
   int                   run,                /**< number of the run */
   SCIP_Real*            objcoef             /**< pointer to store the objective coefficient */
   );

/**@} */

#ifdef __cplusplus
}
#endif

#endif