source: stable/2.7/Cbc/src/CbcEventHandler.hpp @ 1664

Last change on this file since 1664 was 1664, checked in by forrest, 8 years ago

changes for bonmin (and gcc 4.6)

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
File size: 6.0 KB
Line 
1/*! \legal
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 1664 2011-06-10 16:03:06Z 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 1664 2011-06-10 16:03:06Z 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        /*! End of search. */
100        endSearch
101    } ;
102
103    /*! \brief Action codes returned by the event handler.
104
105        Specific values are chosen to match ClpEventHandler return codes.
106    */
107
108    enum CbcAction { /*! Continue --- no action required. */
109        noAction = -1,
110        /*! Stop --- abort the current run at the next opportunity. */
111        stop = 0,
112        /*! Restart --- restart branch-and-cut search; do not undo root node
113        processing.
114        */
115        restart,
116        /*! RestartRoot --- undo root node and start branch-and-cut afresh. */
117        restartRoot,
118        /*! Add special cuts. */
119        addCuts,
120        /*! Pretend solution never happened. */
121        killSolution
122
123    } ;
124
125    /*! \brief Data type for event/action pairs */
126
127    typedef std::map<CbcEvent, CbcAction> eaMapPair ;
128
129
130    /*! \name Event Processing */
131    //@{
132
133    /*! \brief Return the action to be taken for an event.
134
135      Return the action that should be taken in response to the event passed as
136      the parameter. The default implementation simply reads a return code
137      from a map.
138    */
139    virtual CbcAction event(CbcEvent whichEvent) ;
140
141    //@}
142
143
144    /*! \name Constructors and destructors */
145    //@{
146
147    /*! \brief Default constructor. */
148
149    CbcEventHandler(CbcModel *model = 0) ;
150
151    /*! \brief Copy constructor. */
152
153    CbcEventHandler(const CbcEventHandler &orig) ;
154
155    /*! \brief Assignment. */
156
157    CbcEventHandler& operator=(const CbcEventHandler &rhs) ;
158
159    /*! \brief Clone (virtual) constructor. */
160
161    virtual CbcEventHandler* clone() const ;
162
163    /*! \brief Destructor. */
164
165    virtual ~CbcEventHandler() ;
166
167    //@}
168
169    /*! \name Set/Get methods */
170    //@{
171
172    /*! \brief Set model. */
173
174    inline void setModel(CbcModel *model) {
175        model_ = model ;
176    }
177
178    /*! \brief Get model. */
179
180    inline const CbcModel* getModel() const {
181        return model_ ;
182    }
183
184    /*! \brief Set the default action */
185
186    inline void setDfltAction(CbcAction action) {
187        dfltAction_ = action ;
188    }
189
190    /*! \brief Set the action code associated with an event */
191
192    inline void setAction(CbcEvent event, CbcAction action) {
193        if (eaMap_ == 0) {
194            eaMap_ = new eaMapPair ;
195        }
196        (*eaMap_)[event] = action ;
197    }
198
199    //@}
200
201
202protected:
203
204    /*! \name Data members
205
206       Protected (as opposed to private) to allow access by derived classes.
207    */
208    //@{
209
210    /*! \brief Pointer to associated CbcModel */
211
212    CbcModel *model_ ;
213
214    /*! \brief Default action */
215
216    CbcAction dfltAction_ ;
217
218    /*! \brief Pointer to a map that holds non-default event/action pairs */
219
220    eaMapPair *eaMap_ ;
221
222    //@}
223} ;
224
225#endif
226
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