dualascent.h

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/*         SCIP --- Solving Constraint Integer Programs                      */
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/*    Copyright (C) 2002-2022 Konrad-Zuse-Zentrum                            */
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/**@file   dualascent.h
 * @brief  Includes dual-ascent for classic Steiner tree and some variants.
 * @author Daniel Rehfeldt
 *
 *
 */

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

#ifndef APPLICATIONS_STP_SRC_DUALASCENT_H_
#define APPLICATIONS_STP_SRC_DUALASCENT_H_

#include "scip/scip.h"
#include "graph.h"


#ifdef __cplusplus
extern "C" {
#endif



/** reduced cost parameters */
typedef struct reduce_cost_parameters
{
   SCIP_Bool             addcuts;            /**< should dual ascent add Steiner cuts? */
   SCIP_Bool             ascendandprune;     /**< should the ascent-and-prune heuristic be executed? */
   int                   root;               /**< the root */
   SCIP_Bool             is_pseudoroot;      /**< is the root a pseudo root? */
   SCIP_Real             damaxdeviation;      /**< maximum deviation for dual-ascent ( -1.0 for default) */
} DAPARAMS;


/** dual ascent heuristic */
SCIP_RETCODE dualascent_exec(
   SCIP*                 scip,               /**< SCIP data structure */
   const GRAPH*          g,                  /**< graph data structure */
   const int*            result,             /**< solution array or NULL */
   const DAPARAMS*       daparams,           /**< parameter */
   SCIP_Real* RESTRICT   redcost,            /**< array to store reduced costs or NULL */
   SCIP_Real*            objval              /**< pointer to store objective value */
   );


/** dual-ascent for reduced costs */
SCIP_RETCODE dualascent_execDegCons(
   SCIP*                 scip,               /**< SCIP data structure */
   const GRAPH*          g,                  /**< graph data structure */
   const int*            result,             /**< solution array or NULL */
   const DAPARAMS*       daparams,           /**< parameter */
   SCIP_Real* RESTRICT   redcost,            /**< array to store reduced costs or NULL */
   SCIP_Real*            objval
   );


/** updates reduced costs with dual ascent heuristic */
SCIP_RETCODE dualascent_update(
   SCIP*                 scip,               /**< SCIP data structure */
   const GRAPH*          g,                  /**< graph data structure */
   const int*            result,             /**< solution array or NULL */
   const DAPARAMS*       daparams,           /**< parameter */
   SCIP_Real* RESTRICT   redcost,            /**< array to store reduced costs */
   SCIP_Real*            objval              /**< pointer to store objective value */
);


/** dual ascent heuristic for the PCSPG and the MWCSP */
SCIP_RETCODE dualascent_execPcMw(
   SCIP*                 scip,               /**< SCIP data structure */
   GRAPH*                g,                  /**< graph data structure */
   SCIP_Real*            redcost,            /**< array to store reduced costs or NULL */
   SCIP_Real*            objval,             /**< pointer to store objective value */
   SCIP_Bool             addcuts,            /**< should dual ascent add Steiner cuts? */
   SCIP_Bool             ascendandprune,     /**< perform ascend-and-prune and add solution? */
   int                   nruns               /**< number of dual ascent runs */
   );


/** path based dual ascent heuristic */
SCIP_RETCODE dualascent_pathsPcMw(
   SCIP*                 scip,               /**< SCIP data structure */
   const GRAPH*          transgraph,         /**< transformed SAP graph */
   SCIP_Real* RESTRICT   redcost,            /**< array to store reduced costs */
   SCIP_Real*            objval,             /**< pointer to store (dual) objective value */
   const int*            result              /**< solution array or NULL */
   );


/** path based dual ascent heuristic */
SCIP_RETCODE dualascent_paths(
   SCIP*                 scip,               /**< SCIP data structure */
   GRAPH*                graph,              /**< graph */
   SCIP_Real* RESTRICT   redcost,            /**< array to store reduced costs */
   SCIP_Real*            objval,             /**< pointer to store (dual) objective value */
   const int*            result              /**< solution array or NULL */
   );


/** can all terminal be reached via reduced costs from given root? */
SCIP_Bool dualascent_allTermsReachable(
   SCIP*                 scip,               /**< SCIP */
   const GRAPH*          g,                  /**< graph */
   int                   root,               /**< root for reduced costs */
   const SCIP_Real*      redcost             /**< reduced costs */
);



#ifdef __cplusplus
}
#endif


#endif /* APPLICATIONS_STP_SRC_DUALASCENT_H_ */