Improved documentation...
[libdai.git] / include / dai / var.h
1 /* Copyright (C) 2006-2008 Joris Mooij [joris dot mooij at tuebingen dot mpg dot de]
2 Radboud University Nijmegen, The Netherlands /
3 Max Planck Institute for Biological Cybernetics, Germany
4
5 Copyright (C) 2002 Martijn Leisink [martijn@mbfys.kun.nl]
6 Radboud University Nijmegen, The Netherlands
7
8 This file is part of libDAI.
9
10 libDAI is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2 of the License, or
13 (at your option) any later version.
14
15 libDAI is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
19
20 You should have received a copy of the GNU General Public License
21 along with libDAI; if not, write to the Free Software
22 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25
26 /// \file
27 /// \brief Defines class Var
28
29
30 #ifndef __defined_libdai_var_h
31 #define __defined_libdai_var_h
32
33
34 #include <iostream>
35
36
37 namespace dai {
38
39
40 /// Represents a discrete random variable.
41 /** A Var stores the \a label of the variable (an integer-valued unique ID)
42 * and the number of possible values (\a states) of that variable. Two
43 * Var objects with the same label are assumed to be identical (i.e., it
44 * is assumed that their states are also the same).
45 *
46 * In this manual, we use the following notational conventions. The discrete
47 * random variable with label \f$l\f$ is denoted as \f$x_l\f$, and the number
48 * of possible values of this variable as \f$S_l\f$; this is represented in
49 * code by the object Var(\f$l\f$,\f$S_l\f$).
50 */
51 class Var {
52 private:
53 /// Label of the variable (its unique ID)
54 long _label;
55
56 /// Number of possible values
57 size_t _states;
58
59 public:
60 /// Default constructor
61 Var() : _label(-1), _states(0) {}
62 /// Constructor
63 Var( long label, size_t states ) : _label(label), _states(states) {}
64
65 /// Returns the label
66 long label() const { return _label; }
67 /// Returns reference to label
68 long & label() { return _label; }
69
70 /// Returns the number of states
71 size_t states () const { return _states; }
72 /// Returns reference to number of states
73 size_t& states () { return _states; }
74
75 /// Smaller-than operator (compares only labels)
76 bool operator < ( const Var& n ) const { return( _label < n._label ); }
77 /// Larger-than operator (compares only labels)
78 bool operator > ( const Var& n ) const { return( _label > n._label ); }
79 /// Smaller-than-or-equal-to operator (compares only labels)
80 bool operator <= ( const Var& n ) const { return( _label <= n._label ); }
81 /// Larger-than-or-equal-to operator (compares only labels)
82 bool operator >= ( const Var& n ) const { return( _label >= n._label ); }
83 /// Not-equal-to operator (compares only labels)
84 bool operator != ( const Var& n ) const { return( _label != n._label ); }
85 /// Equal-to operator (compares only labels)
86 bool operator == ( const Var& n ) const { return( _label == n._label ); }
87
88 /// Writes a Var to an output stream
89 friend std::ostream& operator << ( std::ostream& os, const Var& n ) {
90 return( os << "x" << n.label() );
91 }
92 };
93
94
95 } // end of namespace dai
96
97
98 #endif