Scippy

SCIP

Solving Constraint Integer Programs

type_conflict.h
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4/* SCIP --- Solving Constraint Integer Programs */
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24
25/**@file type_conflict.h
26 * @ingroup TYPEDEFINITIONS
27 * @brief type definitions for conflict analysis
28 * @author Tobias Achterberg
29 *
30 * This file defines the interface for conflict handler implemented in C.
31 *
32 */
33
34/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
35
36#ifndef __SCIP_TYPE_CONFLICT_H__
37#define __SCIP_TYPE_CONFLICT_H__
38
39#include "scip/def.h"
40#include "scip/type_scip.h"
41#include "scip/type_retcode.h"
42#include "scip/type_result.h"
43#include "scip/type_tree.h"
44
45#ifdef __cplusplus
46extern "C" {
47#endif
48
49typedef struct SCIP_Conflicthdlr SCIP_CONFLICTHDLR; /**< conflict handler to process conflict sets */
50typedef struct SCIP_ConflicthdlrData SCIP_CONFLICTHDLRDATA; /**< conflict handler data */
51typedef struct SCIP_ConflictSet SCIP_CONFLICTSET; /**< set of conflicting bound changes */
52typedef struct SCIP_ProofSet SCIP_PROOFSET; /**< set of variables and coefficients describing a proof-constraint of type a^Tx <= rhs */
53typedef struct SCIP_LPBdChgs SCIP_LPBDCHGS; /**< set of LP bound changes */
54typedef struct SCIP_Conflict SCIP_CONFLICT; /**< conflict analysis data structure */
55
56/** types of conflicts */
58{
59 SCIP_CONFTYPE_UNKNOWN = 0, /**< unknown type */
60 SCIP_CONFTYPE_PROPAGATION = 1, /**< conflict results from propagation */
61 SCIP_CONFTYPE_INFEASLP = 2, /**< conflict results from an infeasible LP relaxation */
62 SCIP_CONFTYPE_BNDEXCEEDING = 3, /**< conflict results from a boundexceeding LP relaxation */
63 SCIP_CONFTYPE_ALTINFPROOF = 4, /**< alternative proof of an infeasible LP relaxation */
64 SCIP_CONFTYPE_ALTBNDPROOF = 5 /**< alternative proof of a boundexceeding LP relaxation */
65};
67
68/** dualray presolving strategy */
70{
71 SCIP_CONFPRES_DISABLED = 0, /**< no presolving */
72 SCIP_CONFPRES_ONLYLOCAL = 1, /**< keep variables contributing with its local bound */
73 SCIP_CONFPRES_ONLYGLOBAL = 2, /**< keep variables contributing with its global bound */
74 SCIP_CONFPRES_BOTH = 3 /**< keep variables contributing with its global bound and add a few
75 * variables contributing with its local bound such that the
76 * constraint is not globally redundant
77 */
78};
80
81/** copy method for conflict handler plugins (called when SCIP copies plugins)
82 *
83 * input:
84 * - scip : SCIP main data structure
85 * - conflicthdlr : the conflict handler itself
86 */
87#define SCIP_DECL_CONFLICTCOPY(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)
88
89/** destructor of conflict handler to free conflict handler data (called when SCIP is exiting)
90 *
91 * input:
92 * - scip : SCIP main data structure
93 * - conflicthdlr : the conflict handler itself
94 */
95#define SCIP_DECL_CONFLICTFREE(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)
96
97/** initialization method of conflict handler (called after problem was transformed)
98 *
99 * input:
100 * - scip : SCIP main data structure
101 * - conflicthdlr : the conflict handler itself
102 */
103#define SCIP_DECL_CONFLICTINIT(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)
104
105/** deinitialization method of conflict handler (called before transformed problem is freed)
106 *
107 * input:
108 * - scip : SCIP main data structure
109 * - conflicthdlr : the conflict handler itself
110 */
111#define SCIP_DECL_CONFLICTEXIT(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)
112
113/** solving process initialization method of conflict handler (called when branch and bound process is about to begin)
114 *
115 * This method is called when the presolving was finished and the branch and bound process is about to begin.
116 * The conflict handler may use this call to initialize its branch and bound specific data.
117 *
118 * input:
119 * - scip : SCIP main data structure
120 * - conflicthdlr : the conflict handler itself
121 */
122#define SCIP_DECL_CONFLICTINITSOL(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)
123
124/** solving process deinitialization method of conflict handler (called before branch and bound process data is freed)
125 *
126 * This method is called before the branch and bound process is freed.
127 * The conflict handler should use this call to clean up its branch and bound data.
128 *
129 * input:
130 * - scip : SCIP main data structure
131 * - conflicthdlr : the conflict handler itself
132 */
133#define SCIP_DECL_CONFLICTEXITSOL(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr)
134
135/** conflict processing method of conflict handler (called when conflict was found)
136 *
137 * This method is called, when the conflict analysis found a conflict on variable bounds.
138 * The conflict handler may update its data accordingly and create a constraint out of the conflict set.
139 * If the parameter "resolved" is set, the conflict handler should not create a constraint, because
140 * a different conflict handler with higher priority already created a constraint.
141 * The bounds in the conflict set lead to a conflict (i.e. an infeasibility) when all enforced at the same time.
142 * Thus, a feasible conflict constraint must demand that at least one of the variables in the conflict
143 * set violates its corresponding bound, i.e., fulfills the negation of the bound change in the conflict set.
144 * For continuous variables, the negation has to be defined in a relaxed way: if, e.g., the bound in the conflict
145 * set is "x <= u", the negation to be used has to be "x >= u", and not "x > u".
146 * The given "bdchginfos" array representing the conflict set is only a reference to an internal
147 * buffer, that may be modified at any time by SCIP. The user must copy the needed information from the
148 * "bdchginfos" array to own data structures, if (s)he wants to use the information later.
149 * (S)he should not keep a pointer to the array or pointers to the single bdchginfos in the array, because these
150 * may get invalid afterwards.
151 *
152 * input:
153 * - scip : SCIP main data structure
154 * - conflicthdlr : the conflict handler itself
155 * - node : node to add resulting conflict constraint to (with SCIPaddConsNode())
156 * - validnode : node at which the conflict constraint is valid (should be passed to SCIPaddConsNode())
157 * - bdchginfos : array with bound changes that lead to a conflict
158 * - relaxedbds : array with relaxed bounds which are efficient to create a valid conflict
159 * - nbdchginfos : number of bound changes in the conflict set
160 * -.primalbound : the current primal bound, or -infininity if the conflict arises from an infeasible LP
161 * - separate : should the conflict constraint be separated?
162 * - local : is the conflict set only valid locally, i.e., should the constraint be created as local constraint?
163 * - dynamic : should the conflict constraint be made subject to aging?
164 * - removable : should the conflict's relaxation be made subject to LP aging and cleanup?
165 * - resolved : is the conflict set already used to create a constraint?
166 * - result : pointer to store the result of the conflict processing call
167 *
168 * possible return values for *result:
169 * - SCIP_CONSADDED : the conflict handler created a constraint out of the conflict set
170 * - SCIP_DIDNOTFIND : the conflict handler could not create a constraint out of the conflict set
171 * - SCIP_DIDNOTRUN : the conflict handler was skipped
172 */
173#define SCIP_DECL_CONFLICTEXEC(x) SCIP_RETCODE x (SCIP* scip, SCIP_CONFLICTHDLR* conflicthdlr, SCIP_NODE* node, \
174 SCIP_NODE* validnode, SCIP_BDCHGINFO** bdchginfos, SCIP_Real* relaxedbds, int nbdchginfos, SCIP_CONFTYPE conftype, \
175 SCIP_Bool cutoffinvolved, SCIP_Bool separate, SCIP_Bool local, SCIP_Bool dynamic, SCIP_Bool removable, \
176 SCIP_Bool resolved, SCIP_RESULT* result)
177
178#ifdef __cplusplus
179}
180#endif
181
182#endif
common defines and data types used in all packages of SCIP
enum SCIP_ConflictPresolStrat SCIP_CONFPRES
Definition: type_conflict.h:79
SCIP_ConflictType
Definition: type_conflict.h:58
@ SCIP_CONFTYPE_ALTINFPROOF
Definition: type_conflict.h:63
@ SCIP_CONFTYPE_BNDEXCEEDING
Definition: type_conflict.h:62
@ SCIP_CONFTYPE_PROPAGATION
Definition: type_conflict.h:60
@ SCIP_CONFTYPE_ALTBNDPROOF
Definition: type_conflict.h:64
@ SCIP_CONFTYPE_INFEASLP
Definition: type_conflict.h:61
@ SCIP_CONFTYPE_UNKNOWN
Definition: type_conflict.h:59
enum SCIP_ConflictType SCIP_CONFTYPE
Definition: type_conflict.h:66
SCIP_ConflictPresolStrat
Definition: type_conflict.h:70
@ SCIP_CONFPRES_ONLYLOCAL
Definition: type_conflict.h:72
@ SCIP_CONFPRES_ONLYGLOBAL
Definition: type_conflict.h:73
@ SCIP_CONFPRES_DISABLED
Definition: type_conflict.h:71
@ SCIP_CONFPRES_BOTH
Definition: type_conflict.h:74
struct SCIP_ConflicthdlrData SCIP_CONFLICTHDLRDATA
Definition: type_conflict.h:50
result codes for SCIP callback methods
type definitions for return codes for SCIP methods
type definitions for SCIP's main datastructure
type definitions for branch and bound tree