source: trunk/Cbc/src/CbcEventHandler.hpp @ 1632

Last change on this file since 1632 was 1632, checked in by forrest, 8 years ago

change NULL to 0 for gcc 4.6!

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
File size: 6.1 KB
Line 
1/*
2  Copyright (C) 2006, International Business Machines Corporation and others.
3  All Rights Reserved.
4
5  This code is licensed under the terms of the Eclipse Public License (EPL).
6
7  $Id: CbcEventHandler.hpp 1632 2011-03-29 14:40:46Z forrest $
8*/
9
10#ifndef CbcEventHandler_H
11#define CbcEventHandler_H
12
13/*! \file CbcEventHandler.hpp
14    \brief Event handling for cbc
15
16  This file contains the declaration of CbcEventHandler, used for event
17  handling in cbc.
18
19  The central method is CbcEventHandler::event(). The default semantics of
20  this call are `ask for the action to take in reponse to this event'. The
21  call is made at the point in the code where the event occurs (<i>e.g.</i>,
22  when a solution is found, or when a node is added to or removed from the
23  search tree). The return value specifies the action to perform in response
24  to the event (<i>e.g.</i>, continue, or stop).
25
26  This is a lazy class. Initially, it knows nothing about specific events,
27  and returns dfltAction_ for any event. This makes for a trivial constructor
28  and fast startup. The only place where the list of known events or actions
29  is hardwired is in the enum definitions for CbcEvent and CbcAction,
30  respectively.
31
32  At the first call to setAction, a map is created to hold (Event,Action)
33  pairs, and this map will be consulted ever after. Events not in the map
34  will still return the default value.
35
36  For serious extensions, derive a subclass and replace event() with a
37  function that suits you better.  The function has access to the CbcModel
38  via a pointer held in the CbcEventHandler object, and can do as much
39  thinking as it likes before returning an answer.  You can also print as
40  much information as you want. The model is held as a const, however, so
41  you can't alter reality.
42
43  The design of the class deliberately matches ClpEventHandler, so that other
44  solvers can participate in cbc without breaking the patterns set by
45  clp-specific code.
46
47*/
48
49#include <map>
50
51/* May well already be declared, but can't hurt. */
52
53class CbcModel ;
54
55/*
56  cvs/svn: $Id: CbcEventHandler.hpp 1632 2011-03-29 14:40:46Z forrest $
57*/
58
59/*! \class CbcEventHandler
60    \brief Base class for Cbc event handling.
61
62  Up front: We're not talking about unanticipated events here. We're talking
63  about anticipated events, in the sense that the code is going to make a call
64  to event() and is prepared to obey the return value that it receives.
65
66  The general pattern for usage is as follows:
67  <ol>
68    <li> Create a CbcEventHandler object. This will be initialised with a set
69         of default actions for every recognised event.
70
71    <li> Attach the event handler to the CbcModel object.
72
73    <li> When execution reaches the point where an event occurs, call the
74         event handler as CbcEventHandler::event(the event). The return value
75         will specify what the code should do in response to the event.
76  </ol>
77
78  The return value associated with an event can be changed at any time.
79*/
80
81class CbcEventHandler {
82
83public:
84
85    /*! \brief Events known to cbc */
86
87    enum CbcEvent { /*! Processing of the current node is complete. */
88        node = 200,
89        /*! A tree status interval has arrived. */
90        treeStatus,
91        /*! A solution has been found. */
92        solution,
93        /*! A heuristic solution has been found. */
94        heuristicSolution,
95        /*! A solution will be found unless user takes action (first check). */
96        beforeSolution1,
97        /*! A solution will be found unless user takes action (thorough check). */
98        beforeSolution2,
99        /*! After failed heuristic. */
100        afterHeuristic,
101        /*! End of search. */
102        endSearch
103    } ;
104
105    /*! \brief Action codes returned by the event handler.
106
107        Specific values are chosen to match ClpEventHandler return codes.
108    */
109
110    enum CbcAction { /*! Continue --- no action required. */
111        noAction = -1,
112        /*! Stop --- abort the current run at the next opportunity. */
113        stop = 0,
114        /*! Restart --- restart branch-and-cut search; do not undo root node
115        processing.
116        */
117        restart,
118        /*! RestartRoot --- undo root node and start branch-and-cut afresh. */
119        restartRoot,
120        /*! Add special cuts. */
121        addCuts,
122        /*! Pretend solution never happened. */
123        killSolution
124
125    } ;
126
127    /*! \brief Data type for event/action pairs */
128
129    typedef std::map<CbcEvent, CbcAction> eaMapPair ;
130
131
132    /*! \name Event Processing */
133    //@{
134
135    /*! \brief Return the action to be taken for an event.
136
137      Return the action that should be taken in response to the event passed as
138      the parameter. The default implementation simply reads a return code
139      from a map.
140    */
141    virtual CbcAction event(CbcEvent whichEvent) ;
142
143    //@}
144
145
146    /*! \name Constructors and destructors */
147    //@{
148
149    /*! \brief Default constructor. */
150
151    CbcEventHandler(CbcModel *model = 0 /* was NULL but 4.6 complains */) ;
152
153    /*! \brief Copy constructor. */
154
155    CbcEventHandler(const CbcEventHandler &orig) ;
156
157    /*! \brief Assignment. */
158
159    CbcEventHandler& operator=(const CbcEventHandler &rhs) ;
160
161    /*! \brief Clone (virtual) constructor. */
162
163    virtual CbcEventHandler* clone() const ;
164
165    /*! \brief Destructor. */
166
167    virtual ~CbcEventHandler() ;
168
169    //@}
170
171    /*! \name Set/Get methods */
172    //@{
173
174    /*! \brief Set model. */
175
176    inline void setModel(CbcModel *model) {
177        model_ = model ;
178    }
179
180    /*! \brief Get model. */
181
182    inline const CbcModel* getModel() const {
183        return model_ ;
184    }
185
186    /*! \brief Set the default action */
187
188    inline void setDfltAction(CbcAction action) {
189        dfltAction_ = action ;
190    }
191
192    /*! \brief Set the action code associated with an event */
193
194    inline void setAction(CbcEvent event, CbcAction action) {
195        if (eaMap_ == 0) {
196            eaMap_ = new eaMapPair ;
197        }
198        (*eaMap_)[event] = action ;
199    }
200
201    //@}
202
203
204protected:
205
206    /*! \name Data members
207
208       Protected (as opposed to private) to allow access by derived classes.
209    */
210    //@{
211
212    /*! \brief Pointer to associated CbcModel */
213
214    CbcModel *model_ ;
215
216    /*! \brief Default action */
217
218    CbcAction dfltAction_ ;
219
220    /*! \brief Pointer to a map that holds non-default event/action pairs */
221
222    eaMapPair *eaMap_ ;
223
224    //@}
225} ;
226
227#endif
228
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