1.1 --- a/lemon/bellman_ford.h	Sun Feb 28 19:23:01 2010 +0100
     1.2 +++ b/lemon/bellman_ford.h	Sun Feb 28 19:38:29 2010 +0100
     1.3 @@ -28,24 +28,27 @@
     1.4  #include <lemon/core.h>
     1.5  #include <lemon/error.h>
     1.6  #include <lemon/maps.h>
     1.7 +#include <lemon/tolerance.h>
     1.8  #include <lemon/path.h>
     1.9  
    1.10  #include <limits>
    1.11  
    1.12  namespace lemon {
    1.13  
    1.14 -  /// \brief Default OperationTraits for the BellmanFord algorithm class.
    1.15 +  /// \brief Default operation traits for the BellmanFord algorithm class.
    1.16    ///  
    1.17    /// This operation traits class defines all computational operations
    1.18    /// and constants that are used in the Bellman-Ford algorithm.
    1.19    /// The default implementation is based on the \c numeric_limits class.
    1.20    /// If the numeric type does not have infinity value, then the maximum
    1.21    /// value is used as extremal infinity value.
    1.22 +  ///
    1.23 +  /// \see BellmanFordToleranceOperationTraits
    1.24    template <
    1.25      typename V, 
    1.26      bool has_inf = std::numeric_limits<V>::has_infinity>
    1.27    struct BellmanFordDefaultOperationTraits {
    1.28 -    /// \e
    1.29 +    /// \brief Value type for the algorithm.
    1.30      typedef V Value;
    1.31      /// \brief Gives back the zero value of the type.
    1.32      static Value zero() {
    1.33 @@ -84,6 +87,51 @@
    1.34      }
    1.35    };
    1.36    
    1.37 +  /// \brief Operation traits for the BellmanFord algorithm class
    1.38 +  /// using tolerance.
    1.39 +  ///
    1.40 +  /// This operation traits class defines all computational operations
    1.41 +  /// and constants that are used in the Bellman-Ford algorithm.
    1.42 +  /// The only difference between this implementation and
    1.43 +  /// \ref BellmanFordDefaultOperationTraits is that this class uses
    1.44 +  /// the \ref Tolerance "tolerance technique" in its \ref less()
    1.45 +  /// function.
    1.46 +  ///
    1.47 +  /// \tparam V The value type.
    1.48 +  /// \tparam eps The epsilon value for the \ref less() function.
    1.49 +  /// By default, it is the epsilon value used by \ref Tolerance
    1.50 +  /// "Tolerance<V>".
    1.51 +  ///
    1.52 +  /// \see BellmanFordDefaultOperationTraits
    1.53 +#ifdef DOXYGEN
    1.54 +  template <typename V, V eps>
    1.55 +#else
    1.56 +  template <
    1.57 +    typename V,
    1.58 +    V eps = Tolerance<V>::def_epsilon>
    1.59 +#endif
    1.60 +  struct BellmanFordToleranceOperationTraits {
    1.61 +    /// \brief Value type for the algorithm.
    1.62 +    typedef V Value;
    1.63 +    /// \brief Gives back the zero value of the type.
    1.64 +    static Value zero() {
    1.65 +      return static_cast<Value>(0);
    1.66 +    }
    1.67 +    /// \brief Gives back the positive infinity value of the type.
    1.68 +    static Value infinity() {
    1.69 +      return std::numeric_limits<Value>::infinity();
    1.70 +    }
    1.71 +    /// \brief Gives back the sum of the given two elements.
    1.72 +    static Value plus(const Value& left, const Value& right) {
    1.73 +      return left + right;
    1.74 +    }
    1.75 +    /// \brief Gives back \c true only if the first value is less than
    1.76 +    /// the second.
    1.77 +    static bool less(const Value& left, const Value& right) {
    1.78 +      return left + eps < right;
    1.79 +    }
    1.80 +  };
    1.81 +
    1.82    /// \brief Default traits class of BellmanFord class.
    1.83    ///
    1.84    /// Default traits class of BellmanFord class.
    1.85 @@ -107,7 +155,8 @@
    1.86      ///
    1.87      /// It defines the used operations and the infinity value for the
    1.88      /// given \c Value type.
    1.89 -    /// \see BellmanFordDefaultOperationTraits
    1.90 +    /// \see BellmanFordDefaultOperationTraits,
    1.91 +    /// BellmanFordToleranceOperationTraits
    1.92      typedef BellmanFordDefaultOperationTraits<Value> OperationTraits;
    1.93   
    1.94      /// \brief The type of the map that stores the last arcs of the 
    1.95 @@ -837,7 +886,8 @@
    1.96      ///
    1.97      /// It defines the used operations and the infinity value for the
    1.98      /// given \c Value type.
    1.99 -    /// \see BellmanFordDefaultOperationTraits
   1.100 +    /// \see BellmanFordDefaultOperationTraits,
   1.101 +    /// BellmanFordToleranceOperationTraits
   1.102      typedef BellmanFordDefaultOperationTraits<Value> OperationTraits;
   1.103  
   1.104      /// \brief The type of the map that stores the last

     2.1 --- a/test/bellman_ford_test.cc	Sun Feb 28 19:23:01 2010 +0100
     2.2 +++ b/test/bellman_ford_test.cc	Sun Feb 28 19:38:29 2010 +0100
     2.3 @@ -104,6 +104,7 @@
     2.4      BF::SetPredMap<concepts::ReadWriteMap<Node,Arc> >
     2.5        ::SetDistMap<concepts::ReadWriteMap<Node,Value> >
     2.6        ::SetOperationTraits<BellmanFordDefaultOperationTraits<Value> >
     2.7 +      ::SetOperationTraits<BellmanFordToleranceOperationTraits<Value, 0> >
     2.8        ::Create bf_test(gr,length);
     2.9  
    2.10      LengthMap length_map;