Scippy

SCIP

Solving Constraint Integer Programs

prop_probing.h
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1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
2 /* */
3 /* This file is part of the program and library */
4 /* SCIP --- Solving Constraint Integer Programs */
5 /* */
6 /* Copyright (C) 2002-2014 Konrad-Zuse-Zentrum */
7 /* fuer Informationstechnik Berlin */
8 /* */
9 /* SCIP is distributed under the terms of the ZIB Academic License. */
10 /* */
11 /* You should have received a copy of the ZIB Academic License */
12 /* along with SCIP; see the file COPYING. If not email to scip@zib.de. */
13 /* */
14 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
15 
16 /**@file prop_probing.h
17  * @ingroup PROPAGATORS
18  * @brief probing propagator
19  * @author Tobias Achterberg
20  */
21 
22 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
23 
24 #ifndef __SCIP_PROP_PROBING_H__
25 #define __SCIP_PROP_PROBING_H__
26 
27 
28 #include "scip/scip.h"
29 
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33 
34 /** creates the probing propagator and includes it in SCIP */
35 extern
36 SCIP_RETCODE SCIPincludePropProbing(
37  SCIP* scip /**< SCIP data structure */
38  );
39 
40 /** applies and evaluates probing of a single variable in the given direction and bound */
41 extern
42 SCIP_RETCODE SCIPapplyProbingVar(
43  SCIP* scip, /**< SCIP data structure */
44  SCIP_VAR** vars, /**< problem variables */
45  int nvars, /**< number of problem variables */
46  int probingpos, /**< variable number to apply probing on */
47  SCIP_BOUNDTYPE boundtype, /**< which bound should be changed */
48  SCIP_Real bound, /**< whioch bound should be set */
49  int maxproprounds, /**< maximal number of propagation rounds (-1: no limit, 0: parameter settings) */
50  SCIP_Real* impllbs, /**< array to store lower bounds after applying implications and cliques */
51  SCIP_Real* implubs, /**< array to store upper bounds after applying implications and cliques */
52  SCIP_Real* proplbs, /**< array to store lower bounds after full propagation */
53  SCIP_Real* propubs, /**< array to store upper bounds after full propagation */
54  SCIP_Bool* cutoff /**< pointer to store whether the probing direction is infeasible */
55  );
56 
57 /** analyses boundchanges resulting from probing on a variable and performs deduced fixations, aggregations, and domain tightenings
58  *
59  * Given a variable probingvar with domain [l,u] and bound tightening results from reducing the
60  * domain once to [l,leftub] and once to [rightlb,u], the method computes and applies resulting
61  * variable fixations, aggregations, implications, and bound changes. Variable probingvar does not
62  * need to be binary. The whole domain of probingvar need to be covered by the left and right
63  * branches, i.e., we assume leftub >= rightlb for continuous variables or floor(leftub) >=
64  * ceil(rightlb)-1 for discrete variables. Bounds after applying implications and cliques do not
65  * need to be provided, but if they are omitted and probingvar is a binary variable, then already
66  * existing implications may be added.
67  */
68 extern
69 SCIP_RETCODE SCIPanalyzeDeductionsProbing(
70  SCIP* scip, /**< SCIP data structure */
71  SCIP_VAR* probingvar, /**< the probing variable */
72  SCIP_Real leftub, /**< upper bound of probing variable in left branch */
73  SCIP_Real rightlb, /**< lower bound of probing variable in right branch */
74  int nvars, /**< number of variables which bound changes should be analyzed */
75  SCIP_VAR** vars, /**< variables which bound changes should be analyzed */
76  SCIP_Real* leftimpllbs, /**< lower bounds after applying implications and cliques in left branch, or NULL */
77  SCIP_Real* leftimplubs, /**< upper bounds after applying implications and cliques in left branch, or NULL */
78  SCIP_Real* leftproplbs, /**< lower bounds after applying domain propagation in left branch */
79  SCIP_Real* leftpropubs, /**< upper bounds after applying domain propagation in left branch */
80  SCIP_Real* rightimpllbs, /**< lower bounds after applying implications and cliques in right branch, or NULL */
81  SCIP_Real* rightimplubs, /**< upper bounds after applying implications and cliques in right branch, or NULL */
82  SCIP_Real* rightproplbs, /**< lower bounds after applying domain propagation in right branch */
83  SCIP_Real* rightpropubs, /**< upper bounds after applying domain propagation in right branch */
84  int* nfixedvars, /**< pointer to counter which is increased by the number of deduced variable fixations */
85  int* naggrvars, /**< pointer to counter which is increased by the number of deduced variable aggregations */
86  int* nimplications, /**< pointer to counter which is increased by the number of deduced implications */
87  int* nchgbds, /**< pointer to counter which is increased by the number of deduced bound tightenings */
88  SCIP_Bool* cutoff /**< buffer to store whether a cutoff is detected */
89  );
90 
91 #ifdef __cplusplus
92 }
93 #endif
94 
95 #endif
96