include/dai/var.h

   1 /*  Copyright (C) 2006-2008  Joris Mooij  [j dot mooij at science dot ru dot nl]
   2     Copyright (C) 2002  Martijn Leisink  [martijn@mbfys.kun.nl]
   3     Radboud University Nijmegen, The Netherlands
   4
   5     This file is part of libDAI.
   6
   7     libDAI is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     libDAI is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License
  18     along with libDAI; if not, write to the Free Software
  19     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  20 */
  21
  22
  23 #ifndef __defined_libdai_var_h
  24 #define __defined_libdai_var_h
  25
  26
  27 #include <iostream>
  28
  29
  30 namespace dai {
  31
  32
  33 /// Represents a discrete variable.
  34 /**  It contains the label of the variable, an integer-valued
  35  *  unique ID for that variable, and the number of possible
  36  *  values ("states") of the variable.
  37  */
  38 class Var {
  39     private:
  40         /// Label of the variable (its unique ID)
  41         long    _label;
  42
  43         /// Number of possible values
  44         size_t  _states;
  45
  46     public:
  47         /// Default constructor
  48         Var() : _label(-1), _states(0) {}
  49         /// Constructor
  50         Var( long label, size_t states ) : _label(label), _states(states) {}
  51
  52         /// Returns the label
  53         long label() const { return _label; }
  54         /// Returns reference to label
  55         long & label() { return _label; }
  56
  57         /// Returns the number of states
  58         size_t states () const { return _states; }
  59         /// Returns reference to number of states
  60         size_t& states () { return _states; }
  61
  62         /// Smaller-than operator (only compares labels)
  63         bool operator < ( const Var& n ) const { return( _label <  n._label ); }
  64         /// Larger-than operator (only compares labels)
  65         bool operator > ( const Var& n ) const { return( _label >  n._label ); }
  66         /// Smaller-than-or-equal-to operator (only compares labels)
  67         bool operator <= ( const Var& n ) const { return( _label <= n._label ); }
  68         /// Larger-than-or-equal-to operator (only compares labels)
  69         bool operator >= ( const Var& n ) const { return( _label >= n._label ); }
  70         /// Not-equal-to operator (only compares labels)
  71         bool operator != ( const Var& n ) const { return( _label != n._label ); }
  72         /// Equal-to operator (only compares labels)
  73         bool operator == ( const Var& n ) const { return( _label == n._label ); }
  74
  75         /// Write a Var to output stream
  76         friend std::ostream& operator << ( std::ostream& os, const Var& n ) {
  77             return( os << "[" << n.label() << "]" );
  78         }
  79 };
  80
  81
  82 } // end of namespace dai
  83
  84
  85 #endif