Detailed Description

type definitions for conflict analysis

Author: Tobias Achterberg

This file defines the interface for conflict handler implemented in C.

#include "scip/def.h"
#include "scip/type_retcode.h"
#include "scip/type_result.h"
#include "scip/type_var.h"

Macros
#define	SCIP_DECL_CONFLICTCOPY(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

#define	SCIP_DECL_CONFLICTFREE(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

#define	SCIP_DECL_CONFLICTINIT(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

#define	SCIP_DECL_CONFLICTEXIT(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

#define	SCIP_DECL_CONFLICTINITSOL(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

#define	SCIP_DECL_CONFLICTEXITSOL(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

#define	SCIP_DECL_CONFLICTEXEC(x)

Typedefs
typedef struct SCIP_Conflicthdlr	SCIP_CONFLICTHDLR

typedef struct SCIP_ConflicthdlrData	SCIP_CONFLICTHDLRDATA

typedef struct SCIP_ConflictSet	SCIP_CONFLICTSET

typedef struct SCIP_LPBdChgs	SCIP_LPBDCHGS

typedef struct SCIP_Conflict	SCIP_CONFLICT

Macro Definition Documentation

#define SCIP_DECL_CONFLICTCOPY ( x ) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

copy method for conflict handler plugins (called when SCIP copies plugins)

input:

scip : SCIP main data structure
conflicthdlr : the conflict handler itself

Definition at line 52 of file type_conflict.h.

#define SCIP_DECL_CONFLICTFREE ( x ) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

destructor of conflict handler to free conflict handler data (called when SCIP is exiting)

input:

scip : SCIP main data structure
conflicthdlr : the conflict handler itself

Definition at line 60 of file type_conflict.h.

#define SCIP_DECL_CONFLICTINIT ( x ) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

initialization method of conflict handler (called after problem was transformed)

input:

scip : SCIP main data structure
conflicthdlr : the conflict handler itself

Definition at line 68 of file type_conflict.h.

#define SCIP_DECL_CONFLICTEXIT ( x ) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

deinitialization method of conflict handler (called before transformed problem is freed)

input:

scip : SCIP main data structure
conflicthdlr : the conflict handler itself

Definition at line 76 of file type_conflict.h.

#define SCIP_DECL_CONFLICTINITSOL ( x ) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

solving process initialization method of conflict handler (called when branch and bound process is about to begin)

This method is called when the presolving was finished and the branch and bound process is about to begin. The conflict handler may use this call to initialize its branch and bound specific data.

input:

scip : SCIP main data structure
conflicthdlr : the conflict handler itself

Definition at line 87 of file type_conflict.h.

#define SCIP_DECL_CONFLICTEXITSOL ( x ) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)

solving process deinitialization method of conflict handler (called before branch and bound process data is freed)

This method is called before the branch and bound process is freed. The conflict handler should use this call to clean up its branch and bound data.

input:

scip : SCIP main data structure
conflicthdlr : the conflict handler itself

Definition at line 98 of file type_conflict.h.

#define SCIP_DECL_CONFLICTEXEC ( x )

Value:

SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr, SCIP_NODE* node, \
      SCIP_NODE* validnode, SCIP_BDCHGINFO** bdchginfos, SCIP_Real* relaxedbds, int nbdchginfos, \
      SCIP_Bool separate, SCIP_Bool local, SCIP_Bool dynamic, SCIP_Bool removable, SCIP_Bool resolved, SCIP_RESULT* result)

conflict processing method of conflict handler (called when conflict was found)

This method is called, when the conflict analysis found a conflict on variable bounds. The conflict handler may update its data accordingly and create a constraint out of the conflict set. If the parameter "resolved" is set, the conflict handler should not create a constraint, because a different conflict handler with higher priority already created a constraint. The bounds in the conflict set lead to a conflict (i.e. an infeasibility) when all enforced at the same time. Thus, a feasible conflict constraint must demand that at least one of the variables in the conflict set violates its corresponding bound, i.e., fulfills the negation of the bound change in the conflict set. For continuous variables, the negation has to be defined in a relaxed way: if, e.g., the bound in the conflict set is "x <= u", the negation to be used has to be "x >= u", and not "x > u". The given "bdchginfos" array representing the conflict set is only a reference to an internal buffer, that may be modified at any time by SCIP. The user must copy the needed information from the "bdchginfos" array to own data structures, if (s)he wants to use the information later. (S)he should not keep a pointer to the array or pointers to the single bdchginfos in the array, because these may get invalid afterwards.

input:

scip : SCIP main data structure
conflicthdlr : the conflict handler itself
node : node to add resulting conflict constraint to (with SCIPaddConsNode())
validnode : node at which the conflict constraint is valid (should be passed to SCIPaddConsNode())
bdchginfos : array with bound changes that lead to a conflict
relaxedbds : array with relaxed bounds which are efficient to create a valid conflict
nbdchginfos : number of bound changes in the conflict set
separate : should the conflict constraint be separated?
local : is the conflict set only valid locally, i.e., should the constraint be created as local constraint?
dynamic : should the conflict constraint be made subject to aging?
removable : should the conflict's relaxation be made subject to LP aging and cleanup?
resolved : is the conflict set already used to create a constraint?
result : pointer to store the result of the conflict processing call

possible return values for *result:

SCIP_CONSADDED : the conflict handler created a constraint out of the conflict set
SCIP_DIDNOTFIND : the conflict handler could not create a constraint out of the conflict set
SCIP_DIDNOTRUN : the conflict handler was skipped

Definition at line 137 of file type_conflict.h.