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 /** It contains the \a label of the variable (an integer-valued unique ID)
  42  *  and the number of possible values (\a states) of the variable.
  43  */
  44 class Var {
  45     private:
  46         /// Label of the variable (its unique ID)
  47         long    _label;
  48
  49         /// Number of possible values
  50         size_t  _states;
  51
  52     public:
  53         /// Default constructor
  54         Var() : _label(-1), _states(0) {}
  55         /// Constructor
  56         Var( long label, size_t states ) : _label(label), _states(states) {}
  57
  58         /// Returns the label
  59         long label() const { return _label; }
  60         /// Returns reference to label
  61         long & label() { return _label; }
  62
  63         /// Returns the number of states
  64         size_t states () const { return _states; }
  65         /// Returns reference to number of states
  66         size_t& states () { return _states; }
  67
  68         /// Smaller-than operator (only compares labels)
  69         bool operator < ( const Var& n ) const { return( _label <  n._label ); }
  70         /// Larger-than operator (only compares labels)
  71         bool operator > ( const Var& n ) const { return( _label >  n._label ); }
  72         /// Smaller-than-or-equal-to operator (only compares labels)
  73         bool operator <= ( const Var& n ) const { return( _label <= n._label ); }
  74         /// Larger-than-or-equal-to operator (only compares labels)
  75         bool operator >= ( const Var& n ) const { return( _label >= n._label ); }
  76         /// Not-equal-to operator (only compares labels)
  77         bool operator != ( const Var& n ) const { return( _label != n._label ); }
  78         /// Equal-to operator (only compares labels)
  79         bool operator == ( const Var& n ) const { return( _label == n._label ); }
  80
  81         /// Writes a Var to an output stream
  82         friend std::ostream& operator << ( std::ostream& os, const Var& n ) {
  83             return( os << "[" << n.label() << "]" );
  84         }
  85 };
  86
  87
  88 } // end of namespace dai
  89
  90
  91 #endif