lemon/maps.h
author Peter Kovacs <kpeter@inf.elte.hu>
Thu, 09 Oct 2008 22:41:29 +0200
changeset 318 1e2d6ca80793
parent 313 64f8f7cc6168
child 327 12626fc94ccf
child 463 88ed40ad0d4f
permissions -rw-r--r--
Doc improvements
     1 /* -*- mode: C++; indent-tabs-mode: nil; -*-
     2  *
     3  * This file is a part of LEMON, a generic C++ optimization library.
     4  *
     5  * Copyright (C) 2003-2008
     6  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     7  * (Egervary Research Group on Combinatorial Optimization, EGRES).
     8  *
     9  * Permission to use, modify and distribute this software is granted
    10  * provided that this copyright notice appears in all copies. For
    11  * precise terms see the accompanying LICENSE file.
    12  *
    13  * This software is provided "AS IS" with no warranty of any kind,
    14  * express or implied, and with no claim as to its suitability for any
    15  * purpose.
    16  *
    17  */
    18 
    19 #ifndef LEMON_MAPS_H
    20 #define LEMON_MAPS_H
    21 
    22 #include <iterator>
    23 #include <functional>
    24 #include <vector>
    25 
    26 #include <lemon/core.h>
    27 
    28 ///\file
    29 ///\ingroup maps
    30 ///\brief Miscellaneous property maps
    31 
    32 #include <map>
    33 
    34 namespace lemon {
    35 
    36   /// \addtogroup maps
    37   /// @{
    38 
    39   /// Base class of maps.
    40 
    41   /// Base class of maps. It provides the necessary type definitions
    42   /// required by the map %concepts.
    43   template<typename K, typename V>
    44   class MapBase {
    45   public:
    46     /// \brief The key type of the map.
    47     typedef K Key;
    48     /// \brief The value type of the map.
    49     /// (The type of objects associated with the keys).
    50     typedef V Value;
    51   };
    52 
    53 
    54   /// Null map. (a.k.a. DoNothingMap)
    55 
    56   /// This map can be used if you have to provide a map only for
    57   /// its type definitions, or if you have to provide a writable map,
    58   /// but data written to it is not required (i.e. it will be sent to
    59   /// <tt>/dev/null</tt>).
    60   /// It conforms the \ref concepts::ReadWriteMap "ReadWriteMap" concept.
    61   ///
    62   /// \sa ConstMap
    63   template<typename K, typename V>
    64   class NullMap : public MapBase<K, V> {
    65   public:
    66     typedef MapBase<K, V> Parent;
    67     typedef typename Parent::Key Key;
    68     typedef typename Parent::Value Value;
    69 
    70     /// Gives back a default constructed element.
    71     Value operator[](const Key&) const { return Value(); }
    72     /// Absorbs the value.
    73     void set(const Key&, const Value&) {}
    74   };
    75 
    76   /// Returns a \c NullMap class
    77 
    78   /// This function just returns a \c NullMap class.
    79   /// \relates NullMap
    80   template <typename K, typename V>
    81   NullMap<K, V> nullMap() {
    82     return NullMap<K, V>();
    83   }
    84 
    85 
    86   /// Constant map.
    87 
    88   /// This \ref concepts::ReadMap "readable map" assigns a specified
    89   /// value to each key.
    90   ///
    91   /// In other aspects it is equivalent to \c NullMap.
    92   /// So it conforms the \ref concepts::ReadWriteMap "ReadWriteMap"
    93   /// concept, but it absorbs the data written to it.
    94   ///
    95   /// The simplest way of using this map is through the constMap()
    96   /// function.
    97   ///
    98   /// \sa NullMap
    99   /// \sa IdentityMap
   100   template<typename K, typename V>
   101   class ConstMap : public MapBase<K, V> {
   102   private:
   103     V _value;
   104   public:
   105     typedef MapBase<K, V> Parent;
   106     typedef typename Parent::Key Key;
   107     typedef typename Parent::Value Value;
   108 
   109     /// Default constructor
   110 
   111     /// Default constructor.
   112     /// The value of the map will be default constructed.
   113     ConstMap() {}
   114 
   115     /// Constructor with specified initial value
   116 
   117     /// Constructor with specified initial value.
   118     /// \param v The initial value of the map.
   119     ConstMap(const Value &v) : _value(v) {}
   120 
   121     /// Gives back the specified value.
   122     Value operator[](const Key&) const { return _value; }
   123 
   124     /// Absorbs the value.
   125     void set(const Key&, const Value&) {}
   126 
   127     /// Sets the value that is assigned to each key.
   128     void setAll(const Value &v) {
   129       _value = v;
   130     }
   131 
   132     template<typename V1>
   133     ConstMap(const ConstMap<K, V1> &, const Value &v) : _value(v) {}
   134   };
   135 
   136   /// Returns a \c ConstMap class
   137 
   138   /// This function just returns a \c ConstMap class.
   139   /// \relates ConstMap
   140   template<typename K, typename V>
   141   inline ConstMap<K, V> constMap(const V &v) {
   142     return ConstMap<K, V>(v);
   143   }
   144 
   145   template<typename K, typename V>
   146   inline ConstMap<K, V> constMap() {
   147     return ConstMap<K, V>();
   148   }
   149 
   150 
   151   template<typename T, T v>
   152   struct Const {};
   153 
   154   /// Constant map with inlined constant value.
   155 
   156   /// This \ref concepts::ReadMap "readable map" assigns a specified
   157   /// value to each key.
   158   ///
   159   /// In other aspects it is equivalent to \c NullMap.
   160   /// So it conforms the \ref concepts::ReadWriteMap "ReadWriteMap"
   161   /// concept, but it absorbs the data written to it.
   162   ///
   163   /// The simplest way of using this map is through the constMap()
   164   /// function.
   165   ///
   166   /// \sa NullMap
   167   /// \sa IdentityMap
   168   template<typename K, typename V, V v>
   169   class ConstMap<K, Const<V, v> > : public MapBase<K, V> {
   170   public:
   171     typedef MapBase<K, V> Parent;
   172     typedef typename Parent::Key Key;
   173     typedef typename Parent::Value Value;
   174 
   175     /// Constructor.
   176     ConstMap() {}
   177 
   178     /// Gives back the specified value.
   179     Value operator[](const Key&) const { return v; }
   180 
   181     /// Absorbs the value.
   182     void set(const Key&, const Value&) {}
   183   };
   184 
   185   /// Returns a \c ConstMap class with inlined constant value
   186 
   187   /// This function just returns a \c ConstMap class with inlined
   188   /// constant value.
   189   /// \relates ConstMap
   190   template<typename K, typename V, V v>
   191   inline ConstMap<K, Const<V, v> > constMap() {
   192     return ConstMap<K, Const<V, v> >();
   193   }
   194 
   195 
   196   /// Identity map.
   197 
   198   /// This \ref concepts::ReadMap "read-only map" gives back the given
   199   /// key as value without any modification.
   200   ///
   201   /// \sa ConstMap
   202   template <typename T>
   203   class IdentityMap : public MapBase<T, T> {
   204   public:
   205     typedef MapBase<T, T> Parent;
   206     typedef typename Parent::Key Key;
   207     typedef typename Parent::Value Value;
   208 
   209     /// Gives back the given value without any modification.
   210     Value operator[](const Key &k) const {
   211       return k;
   212     }
   213   };
   214 
   215   /// Returns an \c IdentityMap class
   216 
   217   /// This function just returns an \c IdentityMap class.
   218   /// \relates IdentityMap
   219   template<typename T>
   220   inline IdentityMap<T> identityMap() {
   221     return IdentityMap<T>();
   222   }
   223 
   224 
   225   /// \brief Map for storing values for integer keys from the range
   226   /// <tt>[0..size-1]</tt>.
   227   ///
   228   /// This map is essentially a wrapper for \c std::vector. It assigns
   229   /// values to integer keys from the range <tt>[0..size-1]</tt>.
   230   /// It can be used with some data structures, for example
   231   /// \c UnionFind, \c BinHeap, when the used items are small
   232   /// integers. This map conforms the \ref concepts::ReferenceMap
   233   /// "ReferenceMap" concept.
   234   ///
   235   /// The simplest way of using this map is through the rangeMap()
   236   /// function.
   237   template <typename V>
   238   class RangeMap : public MapBase<int, V> {
   239     template <typename V1>
   240     friend class RangeMap;
   241   private:
   242 
   243     typedef std::vector<V> Vector;
   244     Vector _vector;
   245 
   246   public:
   247 
   248     typedef MapBase<int, V> Parent;
   249     /// Key type
   250     typedef typename Parent::Key Key;
   251     /// Value type
   252     typedef typename Parent::Value Value;
   253     /// Reference type
   254     typedef typename Vector::reference Reference;
   255     /// Const reference type
   256     typedef typename Vector::const_reference ConstReference;
   257 
   258     typedef True ReferenceMapTag;
   259 
   260   public:
   261 
   262     /// Constructor with specified default value.
   263     RangeMap(int size = 0, const Value &value = Value())
   264       : _vector(size, value) {}
   265 
   266     /// Constructs the map from an appropriate \c std::vector.
   267     template <typename V1>
   268     RangeMap(const std::vector<V1>& vector)
   269       : _vector(vector.begin(), vector.end()) {}
   270 
   271     /// Constructs the map from another \c RangeMap.
   272     template <typename V1>
   273     RangeMap(const RangeMap<V1> &c)
   274       : _vector(c._vector.begin(), c._vector.end()) {}
   275 
   276     /// Returns the size of the map.
   277     int size() {
   278       return _vector.size();
   279     }
   280 
   281     /// Resizes the map.
   282 
   283     /// Resizes the underlying \c std::vector container, so changes the
   284     /// keyset of the map.
   285     /// \param size The new size of the map. The new keyset will be the
   286     /// range <tt>[0..size-1]</tt>.
   287     /// \param value The default value to assign to the new keys.
   288     void resize(int size, const Value &value = Value()) {
   289       _vector.resize(size, value);
   290     }
   291 
   292   private:
   293 
   294     RangeMap& operator=(const RangeMap&);
   295 
   296   public:
   297 
   298     ///\e
   299     Reference operator[](const Key &k) {
   300       return _vector[k];
   301     }
   302 
   303     ///\e
   304     ConstReference operator[](const Key &k) const {
   305       return _vector[k];
   306     }
   307 
   308     ///\e
   309     void set(const Key &k, const Value &v) {
   310       _vector[k] = v;
   311     }
   312   };
   313 
   314   /// Returns a \c RangeMap class
   315 
   316   /// This function just returns a \c RangeMap class.
   317   /// \relates RangeMap
   318   template<typename V>
   319   inline RangeMap<V> rangeMap(int size = 0, const V &value = V()) {
   320     return RangeMap<V>(size, value);
   321   }
   322 
   323   /// \brief Returns a \c RangeMap class created from an appropriate
   324   /// \c std::vector
   325 
   326   /// This function just returns a \c RangeMap class created from an
   327   /// appropriate \c std::vector.
   328   /// \relates RangeMap
   329   template<typename V>
   330   inline RangeMap<V> rangeMap(const std::vector<V> &vector) {
   331     return RangeMap<V>(vector);
   332   }
   333 
   334 
   335   /// Map type based on \c std::map
   336 
   337   /// This map is essentially a wrapper for \c std::map with addition
   338   /// that you can specify a default value for the keys that are not
   339   /// stored actually. This value can be different from the default
   340   /// contructed value (i.e. \c %Value()).
   341   /// This type conforms the \ref concepts::ReferenceMap "ReferenceMap"
   342   /// concept.
   343   ///
   344   /// This map is useful if a default value should be assigned to most of
   345   /// the keys and different values should be assigned only to a few
   346   /// keys (i.e. the map is "sparse").
   347   /// The name of this type also refers to this important usage.
   348   ///
   349   /// Apart form that this map can be used in many other cases since it
   350   /// is based on \c std::map, which is a general associative container.
   351   /// However keep in mind that it is usually not as efficient as other
   352   /// maps.
   353   ///
   354   /// The simplest way of using this map is through the sparseMap()
   355   /// function.
   356   template <typename K, typename V, typename Compare = std::less<K> >
   357   class SparseMap : public MapBase<K, V> {
   358     template <typename K1, typename V1, typename C1>
   359     friend class SparseMap;
   360   public:
   361 
   362     typedef MapBase<K, V> Parent;
   363     /// Key type
   364     typedef typename Parent::Key Key;
   365     /// Value type
   366     typedef typename Parent::Value Value;
   367     /// Reference type
   368     typedef Value& Reference;
   369     /// Const reference type
   370     typedef const Value& ConstReference;
   371 
   372     typedef True ReferenceMapTag;
   373 
   374   private:
   375 
   376     typedef std::map<K, V, Compare> Map;
   377     Map _map;
   378     Value _value;
   379 
   380   public:
   381 
   382     /// \brief Constructor with specified default value.
   383     SparseMap(const Value &value = Value()) : _value(value) {}
   384     /// \brief Constructs the map from an appropriate \c std::map, and
   385     /// explicitly specifies a default value.
   386     template <typename V1, typename Comp1>
   387     SparseMap(const std::map<Key, V1, Comp1> &map,
   388               const Value &value = Value())
   389       : _map(map.begin(), map.end()), _value(value) {}
   390 
   391     /// \brief Constructs the map from another \c SparseMap.
   392     template<typename V1, typename Comp1>
   393     SparseMap(const SparseMap<Key, V1, Comp1> &c)
   394       : _map(c._map.begin(), c._map.end()), _value(c._value) {}
   395 
   396   private:
   397 
   398     SparseMap& operator=(const SparseMap&);
   399 
   400   public:
   401 
   402     ///\e
   403     Reference operator[](const Key &k) {
   404       typename Map::iterator it = _map.lower_bound(k);
   405       if (it != _map.end() && !_map.key_comp()(k, it->first))
   406         return it->second;
   407       else
   408         return _map.insert(it, std::make_pair(k, _value))->second;
   409     }
   410 
   411     ///\e
   412     ConstReference operator[](const Key &k) const {
   413       typename Map::const_iterator it = _map.find(k);
   414       if (it != _map.end())
   415         return it->second;
   416       else
   417         return _value;
   418     }
   419 
   420     ///\e
   421     void set(const Key &k, const Value &v) {
   422       typename Map::iterator it = _map.lower_bound(k);
   423       if (it != _map.end() && !_map.key_comp()(k, it->first))
   424         it->second = v;
   425       else
   426         _map.insert(it, std::make_pair(k, v));
   427     }
   428 
   429     ///\e
   430     void setAll(const Value &v) {
   431       _value = v;
   432       _map.clear();
   433     }
   434   };
   435 
   436   /// Returns a \c SparseMap class
   437 
   438   /// This function just returns a \c SparseMap class with specified
   439   /// default value.
   440   /// \relates SparseMap
   441   template<typename K, typename V, typename Compare>
   442   inline SparseMap<K, V, Compare> sparseMap(const V& value = V()) {
   443     return SparseMap<K, V, Compare>(value);
   444   }
   445 
   446   template<typename K, typename V>
   447   inline SparseMap<K, V, std::less<K> > sparseMap(const V& value = V()) {
   448     return SparseMap<K, V, std::less<K> >(value);
   449   }
   450 
   451   /// \brief Returns a \c SparseMap class created from an appropriate
   452   /// \c std::map
   453 
   454   /// This function just returns a \c SparseMap class created from an
   455   /// appropriate \c std::map.
   456   /// \relates SparseMap
   457   template<typename K, typename V, typename Compare>
   458   inline SparseMap<K, V, Compare>
   459     sparseMap(const std::map<K, V, Compare> &map, const V& value = V())
   460   {
   461     return SparseMap<K, V, Compare>(map, value);
   462   }
   463 
   464   /// @}
   465 
   466   /// \addtogroup map_adaptors
   467   /// @{
   468 
   469   /// Composition of two maps
   470 
   471   /// This \ref concepts::ReadMap "read-only map" returns the
   472   /// composition of two given maps. That is to say, if \c m1 is of
   473   /// type \c M1 and \c m2 is of \c M2, then for
   474   /// \code
   475   ///   ComposeMap<M1, M2> cm(m1,m2);
   476   /// \endcode
   477   /// <tt>cm[x]</tt> will be equal to <tt>m1[m2[x]]</tt>.
   478   ///
   479   /// The \c Key type of the map is inherited from \c M2 and the
   480   /// \c Value type is from \c M1.
   481   /// \c M2::Value must be convertible to \c M1::Key.
   482   ///
   483   /// The simplest way of using this map is through the composeMap()
   484   /// function.
   485   ///
   486   /// \sa CombineMap
   487   template <typename M1, typename M2>
   488   class ComposeMap : public MapBase<typename M2::Key, typename M1::Value> {
   489     const M1 &_m1;
   490     const M2 &_m2;
   491   public:
   492     typedef MapBase<typename M2::Key, typename M1::Value> Parent;
   493     typedef typename Parent::Key Key;
   494     typedef typename Parent::Value Value;
   495 
   496     /// Constructor
   497     ComposeMap(const M1 &m1, const M2 &m2) : _m1(m1), _m2(m2) {}
   498 
   499     /// \e
   500     typename MapTraits<M1>::ConstReturnValue
   501     operator[](const Key &k) const { return _m1[_m2[k]]; }
   502   };
   503 
   504   /// Returns a \c ComposeMap class
   505 
   506   /// This function just returns a \c ComposeMap class.
   507   ///
   508   /// If \c m1 and \c m2 are maps and the \c Value type of \c m2 is
   509   /// convertible to the \c Key of \c m1, then <tt>composeMap(m1,m2)[x]</tt>
   510   /// will be equal to <tt>m1[m2[x]]</tt>.
   511   ///
   512   /// \relates ComposeMap
   513   template <typename M1, typename M2>
   514   inline ComposeMap<M1, M2> composeMap(const M1 &m1, const M2 &m2) {
   515     return ComposeMap<M1, M2>(m1, m2);
   516   }
   517 
   518 
   519   /// Combination of two maps using an STL (binary) functor.
   520 
   521   /// This \ref concepts::ReadMap "read-only map" takes two maps and a
   522   /// binary functor and returns the combination of the two given maps
   523   /// using the functor.
   524   /// That is to say, if \c m1 is of type \c M1 and \c m2 is of \c M2
   525   /// and \c f is of \c F, then for
   526   /// \code
   527   ///   CombineMap<M1,M2,F,V> cm(m1,m2,f);
   528   /// \endcode
   529   /// <tt>cm[x]</tt> will be equal to <tt>f(m1[x],m2[x])</tt>.
   530   ///
   531   /// The \c Key type of the map is inherited from \c M1 (\c M1::Key
   532   /// must be convertible to \c M2::Key) and the \c Value type is \c V.
   533   /// \c M2::Value and \c M1::Value must be convertible to the
   534   /// corresponding input parameter of \c F and the return type of \c F
   535   /// must be convertible to \c V.
   536   ///
   537   /// The simplest way of using this map is through the combineMap()
   538   /// function.
   539   ///
   540   /// \sa ComposeMap
   541   template<typename M1, typename M2, typename F,
   542            typename V = typename F::result_type>
   543   class CombineMap : public MapBase<typename M1::Key, V> {
   544     const M1 &_m1;
   545     const M2 &_m2;
   546     F _f;
   547   public:
   548     typedef MapBase<typename M1::Key, V> Parent;
   549     typedef typename Parent::Key Key;
   550     typedef typename Parent::Value Value;
   551 
   552     /// Constructor
   553     CombineMap(const M1 &m1, const M2 &m2, const F &f = F())
   554       : _m1(m1), _m2(m2), _f(f) {}
   555     /// \e
   556     Value operator[](const Key &k) const { return _f(_m1[k],_m2[k]); }
   557   };
   558 
   559   /// Returns a \c CombineMap class
   560 
   561   /// This function just returns a \c CombineMap class.
   562   ///
   563   /// For example, if \c m1 and \c m2 are both maps with \c double
   564   /// values, then
   565   /// \code
   566   ///   combineMap(m1,m2,std::plus<double>())
   567   /// \endcode
   568   /// is equivalent to
   569   /// \code
   570   ///   addMap(m1,m2)
   571   /// \endcode
   572   ///
   573   /// This function is specialized for adaptable binary function
   574   /// classes and C++ functions.
   575   ///
   576   /// \relates CombineMap
   577   template<typename M1, typename M2, typename F, typename V>
   578   inline CombineMap<M1, M2, F, V>
   579   combineMap(const M1 &m1, const M2 &m2, const F &f) {
   580     return CombineMap<M1, M2, F, V>(m1,m2,f);
   581   }
   582 
   583   template<typename M1, typename M2, typename F>
   584   inline CombineMap<M1, M2, F, typename F::result_type>
   585   combineMap(const M1 &m1, const M2 &m2, const F &f) {
   586     return combineMap<M1, M2, F, typename F::result_type>(m1,m2,f);
   587   }
   588 
   589   template<typename M1, typename M2, typename K1, typename K2, typename V>
   590   inline CombineMap<M1, M2, V (*)(K1, K2), V>
   591   combineMap(const M1 &m1, const M2 &m2, V (*f)(K1, K2)) {
   592     return combineMap<M1, M2, V (*)(K1, K2), V>(m1,m2,f);
   593   }
   594 
   595 
   596   /// Converts an STL style (unary) functor to a map
   597 
   598   /// This \ref concepts::ReadMap "read-only map" returns the value
   599   /// of a given functor. Actually, it just wraps the functor and
   600   /// provides the \c Key and \c Value typedefs.
   601   ///
   602   /// Template parameters \c K and \c V will become its \c Key and
   603   /// \c Value. In most cases they have to be given explicitly because
   604   /// a functor typically does not provide \c argument_type and
   605   /// \c result_type typedefs.
   606   /// Parameter \c F is the type of the used functor.
   607   ///
   608   /// The simplest way of using this map is through the functorToMap()
   609   /// function.
   610   ///
   611   /// \sa MapToFunctor
   612   template<typename F,
   613            typename K = typename F::argument_type,
   614            typename V = typename F::result_type>
   615   class FunctorToMap : public MapBase<K, V> {
   616     F _f;
   617   public:
   618     typedef MapBase<K, V> Parent;
   619     typedef typename Parent::Key Key;
   620     typedef typename Parent::Value Value;
   621 
   622     /// Constructor
   623     FunctorToMap(const F &f = F()) : _f(f) {}
   624     /// \e
   625     Value operator[](const Key &k) const { return _f(k); }
   626   };
   627 
   628   /// Returns a \c FunctorToMap class
   629 
   630   /// This function just returns a \c FunctorToMap class.
   631   ///
   632   /// This function is specialized for adaptable binary function
   633   /// classes and C++ functions.
   634   ///
   635   /// \relates FunctorToMap
   636   template<typename K, typename V, typename F>
   637   inline FunctorToMap<F, K, V> functorToMap(const F &f) {
   638     return FunctorToMap<F, K, V>(f);
   639   }
   640 
   641   template <typename F>
   642   inline FunctorToMap<F, typename F::argument_type, typename F::result_type>
   643     functorToMap(const F &f)
   644   {
   645     return FunctorToMap<F, typename F::argument_type,
   646       typename F::result_type>(f);
   647   }
   648 
   649   template <typename K, typename V>
   650   inline FunctorToMap<V (*)(K), K, V> functorToMap(V (*f)(K)) {
   651     return FunctorToMap<V (*)(K), K, V>(f);
   652   }
   653 
   654 
   655   /// Converts a map to an STL style (unary) functor
   656 
   657   /// This class converts a map to an STL style (unary) functor.
   658   /// That is it provides an <tt>operator()</tt> to read its values.
   659   ///
   660   /// For the sake of convenience it also works as a usual
   661   /// \ref concepts::ReadMap "readable map", i.e. <tt>operator[]</tt>
   662   /// and the \c Key and \c Value typedefs also exist.
   663   ///
   664   /// The simplest way of using this map is through the mapToFunctor()
   665   /// function.
   666   ///
   667   ///\sa FunctorToMap
   668   template <typename M>
   669   class MapToFunctor : public MapBase<typename M::Key, typename M::Value> {
   670     const M &_m;
   671   public:
   672     typedef MapBase<typename M::Key, typename M::Value> Parent;
   673     typedef typename Parent::Key Key;
   674     typedef typename Parent::Value Value;
   675 
   676     typedef typename Parent::Key argument_type;
   677     typedef typename Parent::Value result_type;
   678 
   679     /// Constructor
   680     MapToFunctor(const M &m) : _m(m) {}
   681     /// \e
   682     Value operator()(const Key &k) const { return _m[k]; }
   683     /// \e
   684     Value operator[](const Key &k) const { return _m[k]; }
   685   };
   686 
   687   /// Returns a \c MapToFunctor class
   688 
   689   /// This function just returns a \c MapToFunctor class.
   690   /// \relates MapToFunctor
   691   template<typename M>
   692   inline MapToFunctor<M> mapToFunctor(const M &m) {
   693     return MapToFunctor<M>(m);
   694   }
   695 
   696 
   697   /// \brief Map adaptor to convert the \c Value type of a map to
   698   /// another type using the default conversion.
   699 
   700   /// Map adaptor to convert the \c Value type of a \ref concepts::ReadMap
   701   /// "readable map" to another type using the default conversion.
   702   /// The \c Key type of it is inherited from \c M and the \c Value
   703   /// type is \c V.
   704   /// This type conforms the \ref concepts::ReadMap "ReadMap" concept.
   705   ///
   706   /// The simplest way of using this map is through the convertMap()
   707   /// function.
   708   template <typename M, typename V>
   709   class ConvertMap : public MapBase<typename M::Key, V> {
   710     const M &_m;
   711   public:
   712     typedef MapBase<typename M::Key, V> Parent;
   713     typedef typename Parent::Key Key;
   714     typedef typename Parent::Value Value;
   715 
   716     /// Constructor
   717 
   718     /// Constructor.
   719     /// \param m The underlying map.
   720     ConvertMap(const M &m) : _m(m) {}
   721 
   722     /// \e
   723     Value operator[](const Key &k) const { return _m[k]; }
   724   };
   725 
   726   /// Returns a \c ConvertMap class
   727 
   728   /// This function just returns a \c ConvertMap class.
   729   /// \relates ConvertMap
   730   template<typename V, typename M>
   731   inline ConvertMap<M, V> convertMap(const M &map) {
   732     return ConvertMap<M, V>(map);
   733   }
   734 
   735 
   736   /// Applies all map setting operations to two maps
   737 
   738   /// This map has two \ref concepts::WriteMap "writable map" parameters
   739   /// and each write request will be passed to both of them.
   740   /// If \c M1 is also \ref concepts::ReadMap "readable", then the read
   741   /// operations will return the corresponding values of \c M1.
   742   ///
   743   /// The \c Key and \c Value types are inherited from \c M1.
   744   /// The \c Key and \c Value of \c M2 must be convertible from those
   745   /// of \c M1.
   746   ///
   747   /// The simplest way of using this map is through the forkMap()
   748   /// function.
   749   template<typename  M1, typename M2>
   750   class ForkMap : public MapBase<typename M1::Key, typename M1::Value> {
   751     M1 &_m1;
   752     M2 &_m2;
   753   public:
   754     typedef MapBase<typename M1::Key, typename M1::Value> Parent;
   755     typedef typename Parent::Key Key;
   756     typedef typename Parent::Value Value;
   757 
   758     /// Constructor
   759     ForkMap(M1 &m1, M2 &m2) : _m1(m1), _m2(m2) {}
   760     /// Returns the value associated with the given key in the first map.
   761     Value operator[](const Key &k) const { return _m1[k]; }
   762     /// Sets the value associated with the given key in both maps.
   763     void set(const Key &k, const Value &v) { _m1.set(k,v); _m2.set(k,v); }
   764   };
   765 
   766   /// Returns a \c ForkMap class
   767 
   768   /// This function just returns a \c ForkMap class.
   769   /// \relates ForkMap
   770   template <typename M1, typename M2>
   771   inline ForkMap<M1,M2> forkMap(M1 &m1, M2 &m2) {
   772     return ForkMap<M1,M2>(m1,m2);
   773   }
   774 
   775 
   776   /// Sum of two maps
   777 
   778   /// This \ref concepts::ReadMap "read-only map" returns the sum
   779   /// of the values of the two given maps.
   780   /// Its \c Key and \c Value types are inherited from \c M1.
   781   /// The \c Key and \c Value of \c M2 must be convertible to those of
   782   /// \c M1.
   783   ///
   784   /// If \c m1 is of type \c M1 and \c m2 is of \c M2, then for
   785   /// \code
   786   ///   AddMap<M1,M2> am(m1,m2);
   787   /// \endcode
   788   /// <tt>am[x]</tt> will be equal to <tt>m1[x]+m2[x]</tt>.
   789   ///
   790   /// The simplest way of using this map is through the addMap()
   791   /// function.
   792   ///
   793   /// \sa SubMap, MulMap, DivMap
   794   /// \sa ShiftMap, ShiftWriteMap
   795   template<typename M1, typename M2>
   796   class AddMap : public MapBase<typename M1::Key, typename M1::Value> {
   797     const M1 &_m1;
   798     const M2 &_m2;
   799   public:
   800     typedef MapBase<typename M1::Key, typename M1::Value> Parent;
   801     typedef typename Parent::Key Key;
   802     typedef typename Parent::Value Value;
   803 
   804     /// Constructor
   805     AddMap(const M1 &m1, const M2 &m2) : _m1(m1), _m2(m2) {}
   806     /// \e
   807     Value operator[](const Key &k) const { return _m1[k]+_m2[k]; }
   808   };
   809 
   810   /// Returns an \c AddMap class
   811 
   812   /// This function just returns an \c AddMap class.
   813   ///
   814   /// For example, if \c m1 and \c m2 are both maps with \c double
   815   /// values, then <tt>addMap(m1,m2)[x]</tt> will be equal to
   816   /// <tt>m1[x]+m2[x]</tt>.
   817   ///
   818   /// \relates AddMap
   819   template<typename M1, typename M2>
   820   inline AddMap<M1, M2> addMap(const M1 &m1, const M2 &m2) {
   821     return AddMap<M1, M2>(m1,m2);
   822   }
   823 
   824 
   825   /// Difference of two maps
   826 
   827   /// This \ref concepts::ReadMap "read-only map" returns the difference
   828   /// of the values of the two given maps.
   829   /// Its \c Key and \c Value types are inherited from \c M1.
   830   /// The \c Key and \c Value of \c M2 must be convertible to those of
   831   /// \c M1.
   832   ///
   833   /// If \c m1 is of type \c M1 and \c m2 is of \c M2, then for
   834   /// \code
   835   ///   SubMap<M1,M2> sm(m1,m2);
   836   /// \endcode
   837   /// <tt>sm[x]</tt> will be equal to <tt>m1[x]-m2[x]</tt>.
   838   ///
   839   /// The simplest way of using this map is through the subMap()
   840   /// function.
   841   ///
   842   /// \sa AddMap, MulMap, DivMap
   843   template<typename M1, typename M2>
   844   class SubMap : public MapBase<typename M1::Key, typename M1::Value> {
   845     const M1 &_m1;
   846     const M2 &_m2;
   847   public:
   848     typedef MapBase<typename M1::Key, typename M1::Value> Parent;
   849     typedef typename Parent::Key Key;
   850     typedef typename Parent::Value Value;
   851 
   852     /// Constructor
   853     SubMap(const M1 &m1, const M2 &m2) : _m1(m1), _m2(m2) {}
   854     /// \e
   855     Value operator[](const Key &k) const { return _m1[k]-_m2[k]; }
   856   };
   857 
   858   /// Returns a \c SubMap class
   859 
   860   /// This function just returns a \c SubMap class.
   861   ///
   862   /// For example, if \c m1 and \c m2 are both maps with \c double
   863   /// values, then <tt>subMap(m1,m2)[x]</tt> will be equal to
   864   /// <tt>m1[x]-m2[x]</tt>.
   865   ///
   866   /// \relates SubMap
   867   template<typename M1, typename M2>
   868   inline SubMap<M1, M2> subMap(const M1 &m1, const M2 &m2) {
   869     return SubMap<M1, M2>(m1,m2);
   870   }
   871 
   872 
   873   /// Product of two maps
   874 
   875   /// This \ref concepts::ReadMap "read-only map" returns the product
   876   /// of the values of the two given maps.
   877   /// Its \c Key and \c Value types are inherited from \c M1.
   878   /// The \c Key and \c Value of \c M2 must be convertible to those of
   879   /// \c M1.
   880   ///
   881   /// If \c m1 is of type \c M1 and \c m2 is of \c M2, then for
   882   /// \code
   883   ///   MulMap<M1,M2> mm(m1,m2);
   884   /// \endcode
   885   /// <tt>mm[x]</tt> will be equal to <tt>m1[x]*m2[x]</tt>.
   886   ///
   887   /// The simplest way of using this map is through the mulMap()
   888   /// function.
   889   ///
   890   /// \sa AddMap, SubMap, DivMap
   891   /// \sa ScaleMap, ScaleWriteMap
   892   template<typename M1, typename M2>
   893   class MulMap : public MapBase<typename M1::Key, typename M1::Value> {
   894     const M1 &_m1;
   895     const M2 &_m2;
   896   public:
   897     typedef MapBase<typename M1::Key, typename M1::Value> Parent;
   898     typedef typename Parent::Key Key;
   899     typedef typename Parent::Value Value;
   900 
   901     /// Constructor
   902     MulMap(const M1 &m1,const M2 &m2) : _m1(m1), _m2(m2) {}
   903     /// \e
   904     Value operator[](const Key &k) const { return _m1[k]*_m2[k]; }
   905   };
   906 
   907   /// Returns a \c MulMap class
   908 
   909   /// This function just returns a \c MulMap class.
   910   ///
   911   /// For example, if \c m1 and \c m2 are both maps with \c double
   912   /// values, then <tt>mulMap(m1,m2)[x]</tt> will be equal to
   913   /// <tt>m1[x]*m2[x]</tt>.
   914   ///
   915   /// \relates MulMap
   916   template<typename M1, typename M2>
   917   inline MulMap<M1, M2> mulMap(const M1 &m1,const M2 &m2) {
   918     return MulMap<M1, M2>(m1,m2);
   919   }
   920 
   921 
   922   /// Quotient of two maps
   923 
   924   /// This \ref concepts::ReadMap "read-only map" returns the quotient
   925   /// of the values of the two given maps.
   926   /// Its \c Key and \c Value types are inherited from \c M1.
   927   /// The \c Key and \c Value of \c M2 must be convertible to those of
   928   /// \c M1.
   929   ///
   930   /// If \c m1 is of type \c M1 and \c m2 is of \c M2, then for
   931   /// \code
   932   ///   DivMap<M1,M2> dm(m1,m2);
   933   /// \endcode
   934   /// <tt>dm[x]</tt> will be equal to <tt>m1[x]/m2[x]</tt>.
   935   ///
   936   /// The simplest way of using this map is through the divMap()
   937   /// function.
   938   ///
   939   /// \sa AddMap, SubMap, MulMap
   940   template<typename M1, typename M2>
   941   class DivMap : public MapBase<typename M1::Key, typename M1::Value> {
   942     const M1 &_m1;
   943     const M2 &_m2;
   944   public:
   945     typedef MapBase<typename M1::Key, typename M1::Value> Parent;
   946     typedef typename Parent::Key Key;
   947     typedef typename Parent::Value Value;
   948 
   949     /// Constructor
   950     DivMap(const M1 &m1,const M2 &m2) : _m1(m1), _m2(m2) {}
   951     /// \e
   952     Value operator[](const Key &k) const { return _m1[k]/_m2[k]; }
   953   };
   954 
   955   /// Returns a \c DivMap class
   956 
   957   /// This function just returns a \c DivMap class.
   958   ///
   959   /// For example, if \c m1 and \c m2 are both maps with \c double
   960   /// values, then <tt>divMap(m1,m2)[x]</tt> will be equal to
   961   /// <tt>m1[x]/m2[x]</tt>.
   962   ///
   963   /// \relates DivMap
   964   template<typename M1, typename M2>
   965   inline DivMap<M1, M2> divMap(const M1 &m1,const M2 &m2) {
   966     return DivMap<M1, M2>(m1,m2);
   967   }
   968 
   969 
   970   /// Shifts a map with a constant.
   971 
   972   /// This \ref concepts::ReadMap "read-only map" returns the sum of
   973   /// the given map and a constant value (i.e. it shifts the map with
   974   /// the constant). Its \c Key and \c Value are inherited from \c M.
   975   ///
   976   /// Actually,
   977   /// \code
   978   ///   ShiftMap<M> sh(m,v);
   979   /// \endcode
   980   /// is equivalent to
   981   /// \code
   982   ///   ConstMap<M::Key, M::Value> cm(v);
   983   ///   AddMap<M, ConstMap<M::Key, M::Value> > sh(m,cm);
   984   /// \endcode
   985   ///
   986   /// The simplest way of using this map is through the shiftMap()
   987   /// function.
   988   ///
   989   /// \sa ShiftWriteMap
   990   template<typename M, typename C = typename M::Value>
   991   class ShiftMap : public MapBase<typename M::Key, typename M::Value> {
   992     const M &_m;
   993     C _v;
   994   public:
   995     typedef MapBase<typename M::Key, typename M::Value> Parent;
   996     typedef typename Parent::Key Key;
   997     typedef typename Parent::Value Value;
   998 
   999     /// Constructor
  1000 
  1001     /// Constructor.
  1002     /// \param m The undelying map.
  1003     /// \param v The constant value.
  1004     ShiftMap(const M &m, const C &v) : _m(m), _v(v) {}
  1005     /// \e
  1006     Value operator[](const Key &k) const { return _m[k]+_v; }
  1007   };
  1008 
  1009   /// Shifts a map with a constant (read-write version).
  1010 
  1011   /// This \ref concepts::ReadWriteMap "read-write map" returns the sum
  1012   /// of the given map and a constant value (i.e. it shifts the map with
  1013   /// the constant). Its \c Key and \c Value are inherited from \c M.
  1014   /// It makes also possible to write the map.
  1015   ///
  1016   /// The simplest way of using this map is through the shiftWriteMap()
  1017   /// function.
  1018   ///
  1019   /// \sa ShiftMap
  1020   template<typename M, typename C = typename M::Value>
  1021   class ShiftWriteMap : public MapBase<typename M::Key, typename M::Value> {
  1022     M &_m;
  1023     C _v;
  1024   public:
  1025     typedef MapBase<typename M::Key, typename M::Value> Parent;
  1026     typedef typename Parent::Key Key;
  1027     typedef typename Parent::Value Value;
  1028 
  1029     /// Constructor
  1030 
  1031     /// Constructor.
  1032     /// \param m The undelying map.
  1033     /// \param v The constant value.
  1034     ShiftWriteMap(M &m, const C &v) : _m(m), _v(v) {}
  1035     /// \e
  1036     Value operator[](const Key &k) const { return _m[k]+_v; }
  1037     /// \e
  1038     void set(const Key &k, const Value &v) { _m.set(k, v-_v); }
  1039   };
  1040 
  1041   /// Returns a \c ShiftMap class
  1042 
  1043   /// This function just returns a \c ShiftMap class.
  1044   ///
  1045   /// For example, if \c m is a map with \c double values and \c v is
  1046   /// \c double, then <tt>shiftMap(m,v)[x]</tt> will be equal to
  1047   /// <tt>m[x]+v</tt>.
  1048   ///
  1049   /// \relates ShiftMap
  1050   template<typename M, typename C>
  1051   inline ShiftMap<M, C> shiftMap(const M &m, const C &v) {
  1052     return ShiftMap<M, C>(m,v);
  1053   }
  1054 
  1055   /// Returns a \c ShiftWriteMap class
  1056 
  1057   /// This function just returns a \c ShiftWriteMap class.
  1058   ///
  1059   /// For example, if \c m is a map with \c double values and \c v is
  1060   /// \c double, then <tt>shiftWriteMap(m,v)[x]</tt> will be equal to
  1061   /// <tt>m[x]+v</tt>.
  1062   /// Moreover it makes also possible to write the map.
  1063   ///
  1064   /// \relates ShiftWriteMap
  1065   template<typename M, typename C>
  1066   inline ShiftWriteMap<M, C> shiftWriteMap(M &m, const C &v) {
  1067     return ShiftWriteMap<M, C>(m,v);
  1068   }
  1069 
  1070 
  1071   /// Scales a map with a constant.
  1072 
  1073   /// This \ref concepts::ReadMap "read-only map" returns the value of
  1074   /// the given map multiplied from the left side with a constant value.
  1075   /// Its \c Key and \c Value are inherited from \c M.
  1076   ///
  1077   /// Actually,
  1078   /// \code
  1079   ///   ScaleMap<M> sc(m,v);
  1080   /// \endcode
  1081   /// is equivalent to
  1082   /// \code
  1083   ///   ConstMap<M::Key, M::Value> cm(v);
  1084   ///   MulMap<ConstMap<M::Key, M::Value>, M> sc(cm,m);
  1085   /// \endcode
  1086   ///
  1087   /// The simplest way of using this map is through the scaleMap()
  1088   /// function.
  1089   ///
  1090   /// \sa ScaleWriteMap
  1091   template<typename M, typename C = typename M::Value>
  1092   class ScaleMap : public MapBase<typename M::Key, typename M::Value> {
  1093     const M &_m;
  1094     C _v;
  1095   public:
  1096     typedef MapBase<typename M::Key, typename M::Value> Parent;
  1097     typedef typename Parent::Key Key;
  1098     typedef typename Parent::Value Value;
  1099 
  1100     /// Constructor
  1101 
  1102     /// Constructor.
  1103     /// \param m The undelying map.
  1104     /// \param v The constant value.
  1105     ScaleMap(const M &m, const C &v) : _m(m), _v(v) {}
  1106     /// \e
  1107     Value operator[](const Key &k) const { return _v*_m[k]; }
  1108   };
  1109 
  1110   /// Scales a map with a constant (read-write version).
  1111 
  1112   /// This \ref concepts::ReadWriteMap "read-write map" returns the value of
  1113   /// the given map multiplied from the left side with a constant value.
  1114   /// Its \c Key and \c Value are inherited from \c M.
  1115   /// It can also be used as write map if the \c / operator is defined
  1116   /// between \c Value and \c C and the given multiplier is not zero.
  1117   ///
  1118   /// The simplest way of using this map is through the scaleWriteMap()
  1119   /// function.
  1120   ///
  1121   /// \sa ScaleMap
  1122   template<typename M, typename C = typename M::Value>
  1123   class ScaleWriteMap : public MapBase<typename M::Key, typename M::Value> {
  1124     M &_m;
  1125     C _v;
  1126   public:
  1127     typedef MapBase<typename M::Key, typename M::Value> Parent;
  1128     typedef typename Parent::Key Key;
  1129     typedef typename Parent::Value Value;
  1130 
  1131     /// Constructor
  1132 
  1133     /// Constructor.
  1134     /// \param m The undelying map.
  1135     /// \param v The constant value.
  1136     ScaleWriteMap(M &m, const C &v) : _m(m), _v(v) {}
  1137     /// \e
  1138     Value operator[](const Key &k) const { return _v*_m[k]; }
  1139     /// \e
  1140     void set(const Key &k, const Value &v) { _m.set(k, v/_v); }
  1141   };
  1142 
  1143   /// Returns a \c ScaleMap class
  1144 
  1145   /// This function just returns a \c ScaleMap class.
  1146   ///
  1147   /// For example, if \c m is a map with \c double values and \c v is
  1148   /// \c double, then <tt>scaleMap(m,v)[x]</tt> will be equal to
  1149   /// <tt>v*m[x]</tt>.
  1150   ///
  1151   /// \relates ScaleMap
  1152   template<typename M, typename C>
  1153   inline ScaleMap<M, C> scaleMap(const M &m, const C &v) {
  1154     return ScaleMap<M, C>(m,v);
  1155   }
  1156 
  1157   /// Returns a \c ScaleWriteMap class
  1158 
  1159   /// This function just returns a \c ScaleWriteMap class.
  1160   ///
  1161   /// For example, if \c m is a map with \c double values and \c v is
  1162   /// \c double, then <tt>scaleWriteMap(m,v)[x]</tt> will be equal to
  1163   /// <tt>v*m[x]</tt>.
  1164   /// Moreover it makes also possible to write the map.
  1165   ///
  1166   /// \relates ScaleWriteMap
  1167   template<typename M, typename C>
  1168   inline ScaleWriteMap<M, C> scaleWriteMap(M &m, const C &v) {
  1169     return ScaleWriteMap<M, C>(m,v);
  1170   }
  1171 
  1172 
  1173   /// Negative of a map
  1174 
  1175   /// This \ref concepts::ReadMap "read-only map" returns the negative
  1176   /// of the values of the given map (using the unary \c - operator).
  1177   /// Its \c Key and \c Value are inherited from \c M.
  1178   ///
  1179   /// If M::Value is \c int, \c double etc., then
  1180   /// \code
  1181   ///   NegMap<M> neg(m);
  1182   /// \endcode
  1183   /// is equivalent to
  1184   /// \code
  1185   ///   ScaleMap<M> neg(m,-1);
  1186   /// \endcode
  1187   ///
  1188   /// The simplest way of using this map is through the negMap()
  1189   /// function.
  1190   ///
  1191   /// \sa NegWriteMap
  1192   template<typename M>
  1193   class NegMap : public MapBase<typename M::Key, typename M::Value> {
  1194     const M& _m;
  1195   public:
  1196     typedef MapBase<typename M::Key, typename M::Value> Parent;
  1197     typedef typename Parent::Key Key;
  1198     typedef typename Parent::Value Value;
  1199 
  1200     /// Constructor
  1201     NegMap(const M &m) : _m(m) {}
  1202     /// \e
  1203     Value operator[](const Key &k) const { return -_m[k]; }
  1204   };
  1205 
  1206   /// Negative of a map (read-write version)
  1207 
  1208   /// This \ref concepts::ReadWriteMap "read-write map" returns the
  1209   /// negative of the values of the given map (using the unary \c -
  1210   /// operator).
  1211   /// Its \c Key and \c Value are inherited from \c M.
  1212   /// It makes also possible to write the map.
  1213   ///
  1214   /// If M::Value is \c int, \c double etc., then
  1215   /// \code
  1216   ///   NegWriteMap<M> neg(m);
  1217   /// \endcode
  1218   /// is equivalent to
  1219   /// \code
  1220   ///   ScaleWriteMap<M> neg(m,-1);
  1221   /// \endcode
  1222   ///
  1223   /// The simplest way of using this map is through the negWriteMap()
  1224   /// function.
  1225   ///
  1226   /// \sa NegMap
  1227   template<typename M>
  1228   class NegWriteMap : public MapBase<typename M::Key, typename M::Value> {
  1229     M &_m;
  1230   public:
  1231     typedef MapBase<typename M::Key, typename M::Value> Parent;
  1232     typedef typename Parent::Key Key;
  1233     typedef typename Parent::Value Value;
  1234 
  1235     /// Constructor
  1236     NegWriteMap(M &m) : _m(m) {}
  1237     /// \e
  1238     Value operator[](const Key &k) const { return -_m[k]; }
  1239     /// \e
  1240     void set(const Key &k, const Value &v) { _m.set(k, -v); }
  1241   };
  1242 
  1243   /// Returns a \c NegMap class
  1244 
  1245   /// This function just returns a \c NegMap class.
  1246   ///
  1247   /// For example, if \c m is a map with \c double values, then
  1248   /// <tt>negMap(m)[x]</tt> will be equal to <tt>-m[x]</tt>.
  1249   ///
  1250   /// \relates NegMap
  1251   template <typename M>
  1252   inline NegMap<M> negMap(const M &m) {
  1253     return NegMap<M>(m);
  1254   }
  1255 
  1256   /// Returns a \c NegWriteMap class
  1257 
  1258   /// This function just returns a \c NegWriteMap class.
  1259   ///
  1260   /// For example, if \c m is a map with \c double values, then
  1261   /// <tt>negWriteMap(m)[x]</tt> will be equal to <tt>-m[x]</tt>.
  1262   /// Moreover it makes also possible to write the map.
  1263   ///
  1264   /// \relates NegWriteMap
  1265   template <typename M>
  1266   inline NegWriteMap<M> negWriteMap(M &m) {
  1267     return NegWriteMap<M>(m);
  1268   }
  1269 
  1270 
  1271   /// Absolute value of a map
  1272 
  1273   /// This \ref concepts::ReadMap "read-only map" returns the absolute
  1274   /// value of the values of the given map.
  1275   /// Its \c Key and \c Value are inherited from \c M.
  1276   /// \c Value must be comparable to \c 0 and the unary \c -
  1277   /// operator must be defined for it, of course.
  1278   ///
  1279   /// The simplest way of using this map is through the absMap()
  1280   /// function.
  1281   template<typename M>
  1282   class AbsMap : public MapBase<typename M::Key, typename M::Value> {
  1283     const M &_m;
  1284   public:
  1285     typedef MapBase<typename M::Key, typename M::Value> Parent;
  1286     typedef typename Parent::Key Key;
  1287     typedef typename Parent::Value Value;
  1288 
  1289     /// Constructor
  1290     AbsMap(const M &m) : _m(m) {}
  1291     /// \e
  1292     Value operator[](const Key &k) const {
  1293       Value tmp = _m[k];
  1294       return tmp >= 0 ? tmp : -tmp;
  1295     }
  1296 
  1297   };
  1298 
  1299   /// Returns an \c AbsMap class
  1300 
  1301   /// This function just returns an \c AbsMap class.
  1302   ///
  1303   /// For example, if \c m is a map with \c double values, then
  1304   /// <tt>absMap(m)[x]</tt> will be equal to <tt>m[x]</tt> if
  1305   /// it is positive or zero and <tt>-m[x]</tt> if <tt>m[x]</tt> is
  1306   /// negative.
  1307   ///
  1308   /// \relates AbsMap
  1309   template<typename M>
  1310   inline AbsMap<M> absMap(const M &m) {
  1311     return AbsMap<M>(m);
  1312   }
  1313 
  1314   /// @}
  1315 
  1316   // Logical maps and map adaptors:
  1317 
  1318   /// \addtogroup maps
  1319   /// @{
  1320 
  1321   /// Constant \c true map.
  1322 
  1323   /// This \ref concepts::ReadMap "read-only map" assigns \c true to
  1324   /// each key.
  1325   ///
  1326   /// Note that
  1327   /// \code
  1328   ///   TrueMap<K> tm;
  1329   /// \endcode
  1330   /// is equivalent to
  1331   /// \code
  1332   ///   ConstMap<K,bool> tm(true);
  1333   /// \endcode
  1334   ///
  1335   /// \sa FalseMap
  1336   /// \sa ConstMap
  1337   template <typename K>
  1338   class TrueMap : public MapBase<K, bool> {
  1339   public:
  1340     typedef MapBase<K, bool> Parent;
  1341     typedef typename Parent::Key Key;
  1342     typedef typename Parent::Value Value;
  1343 
  1344     /// Gives back \c true.
  1345     Value operator[](const Key&) const { return true; }
  1346   };
  1347 
  1348   /// Returns a \c TrueMap class
  1349 
  1350   /// This function just returns a \c TrueMap class.
  1351   /// \relates TrueMap
  1352   template<typename K>
  1353   inline TrueMap<K> trueMap() {
  1354     return TrueMap<K>();
  1355   }
  1356 
  1357 
  1358   /// Constant \c false map.
  1359 
  1360   /// This \ref concepts::ReadMap "read-only map" assigns \c false to
  1361   /// each key.
  1362   ///
  1363   /// Note that
  1364   /// \code
  1365   ///   FalseMap<K> fm;
  1366   /// \endcode
  1367   /// is equivalent to
  1368   /// \code
  1369   ///   ConstMap<K,bool> fm(false);
  1370   /// \endcode
  1371   ///
  1372   /// \sa TrueMap
  1373   /// \sa ConstMap
  1374   template <typename K>
  1375   class FalseMap : public MapBase<K, bool> {
  1376   public:
  1377     typedef MapBase<K, bool> Parent;
  1378     typedef typename Parent::Key Key;
  1379     typedef typename Parent::Value Value;
  1380 
  1381     /// Gives back \c false.
  1382     Value operator[](const Key&) const { return false; }
  1383   };
  1384 
  1385   /// Returns a \c FalseMap class
  1386 
  1387   /// This function just returns a \c FalseMap class.
  1388   /// \relates FalseMap
  1389   template<typename K>
  1390   inline FalseMap<K> falseMap() {
  1391     return FalseMap<K>();
  1392   }
  1393 
  1394   /// @}
  1395 
  1396   /// \addtogroup map_adaptors
  1397   /// @{
  1398 
  1399   /// Logical 'and' of two maps
  1400 
  1401   /// This \ref concepts::ReadMap "read-only map" returns the logical
  1402   /// 'and' of the values of the two given maps.
  1403   /// Its \c Key type is inherited from \c M1 and its \c Value type is
  1404   /// \c bool. \c M2::Key must be convertible to \c M1::Key.
  1405   ///
  1406   /// If \c m1 is of type \c M1 and \c m2 is of \c M2, then for
  1407   /// \code
  1408   ///   AndMap<M1,M2> am(m1,m2);
  1409   /// \endcode
  1410   /// <tt>am[x]</tt> will be equal to <tt>m1[x]&&m2[x]</tt>.
  1411   ///
  1412   /// The simplest way of using this map is through the andMap()
  1413   /// function.
  1414   ///
  1415   /// \sa OrMap
  1416   /// \sa NotMap, NotWriteMap
  1417   template<typename M1, typename M2>
  1418   class AndMap : public MapBase<typename M1::Key, bool> {
  1419     const M1 &_m1;
  1420     const M2 &_m2;
  1421   public:
  1422     typedef MapBase<typename M1::Key, bool> Parent;
  1423     typedef typename Parent::Key Key;
  1424     typedef typename Parent::Value Value;
  1425 
  1426     /// Constructor
  1427     AndMap(const M1 &m1, const M2 &m2) : _m1(m1), _m2(m2) {}
  1428     /// \e
  1429     Value operator[](const Key &k) const { return _m1[k]&&_m2[k]; }
  1430   };
  1431 
  1432   /// Returns an \c AndMap class
  1433 
  1434   /// This function just returns an \c AndMap class.
  1435   ///
  1436   /// For example, if \c m1 and \c m2 are both maps with \c bool values,
  1437   /// then <tt>andMap(m1,m2)[x]</tt> will be equal to
  1438   /// <tt>m1[x]&&m2[x]</tt>.
  1439   ///
  1440   /// \relates AndMap
  1441   template<typename M1, typename M2>
  1442   inline AndMap<M1, M2> andMap(const M1 &m1, const M2 &m2) {
  1443     return AndMap<M1, M2>(m1,m2);
  1444   }
  1445 
  1446 
  1447   /// Logical 'or' of two maps
  1448 
  1449   /// This \ref concepts::ReadMap "read-only map" returns the logical
  1450   /// 'or' of the values of the two given maps.
  1451   /// Its \c Key type is inherited from \c M1 and its \c Value type is
  1452   /// \c bool. \c M2::Key must be convertible to \c M1::Key.
  1453   ///
  1454   /// If \c m1 is of type \c M1 and \c m2 is of \c M2, then for
  1455   /// \code
  1456   ///   OrMap<M1,M2> om(m1,m2);
  1457   /// \endcode
  1458   /// <tt>om[x]</tt> will be equal to <tt>m1[x]||m2[x]</tt>.
  1459   ///
  1460   /// The simplest way of using this map is through the orMap()
  1461   /// function.
  1462   ///
  1463   /// \sa AndMap
  1464   /// \sa NotMap, NotWriteMap
  1465   template<typename M1, typename M2>
  1466   class OrMap : public MapBase<typename M1::Key, bool> {
  1467     const M1 &_m1;
  1468     const M2 &_m2;
  1469   public:
  1470     typedef MapBase<typename M1::Key, bool> Parent;
  1471     typedef typename Parent::Key Key;
  1472     typedef typename Parent::Value Value;
  1473 
  1474     /// Constructor
  1475     OrMap(const M1 &m1, const M2 &m2) : _m1(m1), _m2(m2) {}
  1476     /// \e
  1477     Value operator[](const Key &k) const { return _m1[k]||_m2[k]; }
  1478   };
  1479 
  1480   /// Returns an \c OrMap class
  1481 
  1482   /// This function just returns an \c OrMap class.
  1483   ///
  1484   /// For example, if \c m1 and \c m2 are both maps with \c bool values,
  1485   /// then <tt>orMap(m1,m2)[x]</tt> will be equal to
  1486   /// <tt>m1[x]||m2[x]</tt>.
  1487   ///
  1488   /// \relates OrMap
  1489   template<typename M1, typename M2>
  1490   inline OrMap<M1, M2> orMap(const M1 &m1, const M2 &m2) {
  1491     return OrMap<M1, M2>(m1,m2);
  1492   }
  1493 
  1494 
  1495   /// Logical 'not' of a map
  1496 
  1497   /// This \ref concepts::ReadMap "read-only map" returns the logical
  1498   /// negation of the values of the given map.
  1499   /// Its \c Key is inherited from \c M and its \c Value is \c bool.
  1500   ///
  1501   /// The simplest way of using this map is through the notMap()
  1502   /// function.
  1503   ///
  1504   /// \sa NotWriteMap
  1505   template <typename M>
  1506   class NotMap : public MapBase<typename M::Key, bool> {
  1507     const M &_m;
  1508   public:
  1509     typedef MapBase<typename M::Key, bool> Parent;
  1510     typedef typename Parent::Key Key;
  1511     typedef typename Parent::Value Value;
  1512 
  1513     /// Constructor
  1514     NotMap(const M &m) : _m(m) {}
  1515     /// \e
  1516     Value operator[](const Key &k) const { return !_m[k]; }
  1517   };
  1518 
  1519   /// Logical 'not' of a map (read-write version)
  1520 
  1521   /// This \ref concepts::ReadWriteMap "read-write map" returns the
  1522   /// logical negation of the values of the given map.
  1523   /// Its \c Key is inherited from \c M and its \c Value is \c bool.
  1524   /// It makes also possible to write the map. When a value is set,
  1525   /// the opposite value is set to the original map.
  1526   ///
  1527   /// The simplest way of using this map is through the notWriteMap()
  1528   /// function.
  1529   ///
  1530   /// \sa NotMap
  1531   template <typename M>
  1532   class NotWriteMap : public MapBase<typename M::Key, bool> {
  1533     M &_m;
  1534   public:
  1535     typedef MapBase<typename M::Key, bool> Parent;
  1536     typedef typename Parent::Key Key;
  1537     typedef typename Parent::Value Value;
  1538 
  1539     /// Constructor
  1540     NotWriteMap(M &m) : _m(m) {}
  1541     /// \e
  1542     Value operator[](const Key &k) const { return !_m[k]; }
  1543     /// \e
  1544     void set(const Key &k, bool v) { _m.set(k, !v); }
  1545   };
  1546 
  1547   /// Returns a \c NotMap class
  1548 
  1549   /// This function just returns a \c NotMap class.
  1550   ///
  1551   /// For example, if \c m is a map with \c bool values, then
  1552   /// <tt>notMap(m)[x]</tt> will be equal to <tt>!m[x]</tt>.
  1553   ///
  1554   /// \relates NotMap
  1555   template <typename M>
  1556   inline NotMap<M> notMap(const M &m) {
  1557     return NotMap<M>(m);
  1558   }
  1559 
  1560   /// Returns a \c NotWriteMap class
  1561 
  1562   /// This function just returns a \c NotWriteMap class.
  1563   ///
  1564   /// For example, if \c m is a map with \c bool values, then
  1565   /// <tt>notWriteMap(m)[x]</tt> will be equal to <tt>!m[x]</tt>.
  1566   /// Moreover it makes also possible to write the map.
  1567   ///
  1568   /// \relates NotWriteMap
  1569   template <typename M>
  1570   inline NotWriteMap<M> notWriteMap(M &m) {
  1571     return NotWriteMap<M>(m);
  1572   }
  1573 
  1574 
  1575   /// Combination of two maps using the \c == operator
  1576 
  1577   /// This \ref concepts::ReadMap "read-only map" assigns \c true to
  1578   /// the keys for which the corresponding values of the two maps are
  1579   /// equal.
  1580   /// Its \c Key type is inherited from \c M1 and its \c Value type is
  1581   /// \c bool. \c M2::Key must be convertible to \c M1::Key.
  1582   ///
  1583   /// If \c m1 is of type \c M1 and \c m2 is of \c M2, then for
  1584   /// \code
  1585   ///   EqualMap<M1,M2> em(m1,m2);
  1586   /// \endcode
  1587   /// <tt>em[x]</tt> will be equal to <tt>m1[x]==m2[x]</tt>.
  1588   ///
  1589   /// The simplest way of using this map is through the equalMap()
  1590   /// function.
  1591   ///
  1592   /// \sa LessMap
  1593   template<typename M1, typename M2>
  1594   class EqualMap : public MapBase<typename M1::Key, bool> {
  1595     const M1 &_m1;
  1596     const M2 &_m2;
  1597   public:
  1598     typedef MapBase<typename M1::Key, bool> Parent;
  1599     typedef typename Parent::Key Key;
  1600     typedef typename Parent::Value Value;
  1601 
  1602     /// Constructor
  1603     EqualMap(const M1 &m1, const M2 &m2) : _m1(m1), _m2(m2) {}
  1604     /// \e
  1605     Value operator[](const Key &k) const { return _m1[k]==_m2[k]; }
  1606   };
  1607 
  1608   /// Returns an \c EqualMap class
  1609 
  1610   /// This function just returns an \c EqualMap class.
  1611   ///
  1612   /// For example, if \c m1 and \c m2 are maps with keys and values of
  1613   /// the same type, then <tt>equalMap(m1,m2)[x]</tt> will be equal to
  1614   /// <tt>m1[x]==m2[x]</tt>.
  1615   ///
  1616   /// \relates EqualMap
  1617   template<typename M1, typename M2>
  1618   inline EqualMap<M1, M2> equalMap(const M1 &m1, const M2 &m2) {
  1619     return EqualMap<M1, M2>(m1,m2);
  1620   }
  1621 
  1622 
  1623   /// Combination of two maps using the \c < operator
  1624 
  1625   /// This \ref concepts::ReadMap "read-only map" assigns \c true to
  1626   /// the keys for which the corresponding value of the first map is
  1627   /// less then the value of the second map.
  1628   /// Its \c Key type is inherited from \c M1 and its \c Value type is
  1629   /// \c bool. \c M2::Key must be convertible to \c M1::Key.
  1630   ///
  1631   /// If \c m1 is of type \c M1 and \c m2 is of \c M2, then for
  1632   /// \code
  1633   ///   LessMap<M1,M2> lm(m1,m2);
  1634   /// \endcode
  1635   /// <tt>lm[x]</tt> will be equal to <tt>m1[x]<m2[x]</tt>.
  1636   ///
  1637   /// The simplest way of using this map is through the lessMap()
  1638   /// function.
  1639   ///
  1640   /// \sa EqualMap
  1641   template<typename M1, typename M2>
  1642   class LessMap : public MapBase<typename M1::Key, bool> {
  1643     const M1 &_m1;
  1644     const M2 &_m2;
  1645   public:
  1646     typedef MapBase<typename M1::Key, bool> Parent;
  1647     typedef typename Parent::Key Key;
  1648     typedef typename Parent::Value Value;
  1649 
  1650     /// Constructor
  1651     LessMap(const M1 &m1, const M2 &m2) : _m1(m1), _m2(m2) {}
  1652     /// \e
  1653     Value operator[](const Key &k) const { return _m1[k]<_m2[k]; }
  1654   };
  1655 
  1656   /// Returns an \c LessMap class
  1657 
  1658   /// This function just returns an \c LessMap class.
  1659   ///
  1660   /// For example, if \c m1 and \c m2 are maps with keys and values of
  1661   /// the same type, then <tt>lessMap(m1,m2)[x]</tt> will be equal to
  1662   /// <tt>m1[x]<m2[x]</tt>.
  1663   ///
  1664   /// \relates LessMap
  1665   template<typename M1, typename M2>
  1666   inline LessMap<M1, M2> lessMap(const M1 &m1, const M2 &m2) {
  1667     return LessMap<M1, M2>(m1,m2);
  1668   }
  1669 
  1670   namespace _maps_bits {
  1671 
  1672     template <typename _Iterator, typename Enable = void>
  1673     struct IteratorTraits {
  1674       typedef typename std::iterator_traits<_Iterator>::value_type Value;
  1675     };
  1676 
  1677     template <typename _Iterator>
  1678     struct IteratorTraits<_Iterator,
  1679       typename exists<typename _Iterator::container_type>::type>
  1680     {
  1681       typedef typename _Iterator::container_type::value_type Value;
  1682     };
  1683 
  1684   }
  1685 
  1686   /// @}
  1687 
  1688   /// \addtogroup maps
  1689   /// @{
  1690 
  1691   /// \brief Writable bool map for logging each \c true assigned element
  1692   ///
  1693   /// A \ref concepts::WriteMap "writable" bool map for logging
  1694   /// each \c true assigned element, i.e it copies subsequently each
  1695   /// keys set to \c true to the given iterator.
  1696   /// The most important usage of it is storing certain nodes or arcs
  1697   /// that were marked \c true by an algorithm.
  1698   ///
  1699   /// There are several algorithms that provide solutions through bool
  1700   /// maps and most of them assign \c true at most once for each key.
  1701   /// In these cases it is a natural request to store each \c true
  1702   /// assigned elements (in order of the assignment), which can be
  1703   /// easily done with LoggerBoolMap.
  1704   ///
  1705   /// The simplest way of using this map is through the loggerBoolMap()
  1706   /// function.
  1707   ///
  1708   /// \tparam It The type of the iterator.
  1709   /// \tparam Ke The key type of the map. The default value set
  1710   /// according to the iterator type should work in most cases.
  1711   ///
  1712   /// \note The container of the iterator must contain enough space
  1713   /// for the elements or the iterator should be an inserter iterator.
  1714 #ifdef DOXYGEN
  1715   template <typename It, typename Ke>
  1716 #else
  1717   template <typename It,
  1718             typename Ke=typename _maps_bits::IteratorTraits<It>::Value>
  1719 #endif
  1720   class LoggerBoolMap {
  1721   public:
  1722     typedef It Iterator;
  1723 
  1724     typedef Ke Key;
  1725     typedef bool Value;
  1726 
  1727     /// Constructor
  1728     LoggerBoolMap(Iterator it)
  1729       : _begin(it), _end(it) {}
  1730 
  1731     /// Gives back the given iterator set for the first key
  1732     Iterator begin() const {
  1733       return _begin;
  1734     }
  1735 
  1736     /// Gives back the the 'after the last' iterator
  1737     Iterator end() const {
  1738       return _end;
  1739     }
  1740 
  1741     /// The set function of the map
  1742     void set(const Key& key, Value value) {
  1743       if (value) {
  1744         *_end++ = key;
  1745       }
  1746     }
  1747 
  1748   private:
  1749     Iterator _begin;
  1750     Iterator _end;
  1751   };
  1752 
  1753   /// Returns a \c LoggerBoolMap class
  1754 
  1755   /// This function just returns a \c LoggerBoolMap class.
  1756   ///
  1757   /// The most important usage of it is storing certain nodes or arcs
  1758   /// that were marked \c true by an algorithm.
  1759   /// For example it makes easier to store the nodes in the processing
  1760   /// order of Dfs algorithm, as the following examples show.
  1761   /// \code
  1762   ///   std::vector<Node> v;
  1763   ///   dfs(g,s).processedMap(loggerBoolMap(std::back_inserter(v))).run();
  1764   /// \endcode
  1765   /// \code
  1766   ///   std::vector<Node> v(countNodes(g));
  1767   ///   dfs(g,s).processedMap(loggerBoolMap(v.begin())).run();
  1768   /// \endcode
  1769   ///
  1770   /// \note The container of the iterator must contain enough space
  1771   /// for the elements or the iterator should be an inserter iterator.
  1772   ///
  1773   /// \note LoggerBoolMap is just \ref concepts::WriteMap "writable", so
  1774   /// it cannot be used when a readable map is needed, for example as
  1775   /// \c ReachedMap for \c Bfs, \c Dfs and \c Dijkstra algorithms.
  1776   ///
  1777   /// \relates LoggerBoolMap
  1778   template<typename Iterator>
  1779   inline LoggerBoolMap<Iterator> loggerBoolMap(Iterator it) {
  1780     return LoggerBoolMap<Iterator>(it);
  1781   }
  1782 
  1783   /// @}
  1784 
  1785   /// \addtogroup graph_maps
  1786   /// @{
  1787 
  1788   /// Provides an immutable and unique id for each item in the graph.
  1789 
  1790   /// The IdMap class provides a unique and immutable id for each item of the
  1791   /// same type (e.g. node) in the graph. This id is <ul><li>\b unique:
  1792   /// different items (nodes) get different ids <li>\b immutable: the id of an
  1793   /// item (node) does not change (even if you delete other nodes).  </ul>
  1794   /// Through this map you get access (i.e. can read) the inner id values of
  1795   /// the items stored in the graph. This map can be inverted with its member
  1796   /// class \c InverseMap or with the \c operator() member.
  1797   ///
  1798   template <typename _Graph, typename _Item>
  1799   class IdMap {
  1800   public:
  1801     typedef _Graph Graph;
  1802     typedef int Value;
  1803     typedef _Item Item;
  1804     typedef _Item Key;
  1805 
  1806     /// \brief Constructor.
  1807     ///
  1808     /// Constructor of the map.
  1809     explicit IdMap(const Graph& graph) : _graph(&graph) {}
  1810 
  1811     /// \brief Gives back the \e id of the item.
  1812     ///
  1813     /// Gives back the immutable and unique \e id of the item.
  1814     int operator[](const Item& item) const { return _graph->id(item);}
  1815 
  1816     /// \brief Gives back the item by its id.
  1817     ///
  1818     /// Gives back the item by its id.
  1819     Item operator()(int id) { return _graph->fromId(id, Item()); }
  1820 
  1821   private:
  1822     const Graph* _graph;
  1823 
  1824   public:
  1825 
  1826     /// \brief The class represents the inverse of its owner (IdMap).
  1827     ///
  1828     /// The class represents the inverse of its owner (IdMap).
  1829     /// \see inverse()
  1830     class InverseMap {
  1831     public:
  1832 
  1833       /// \brief Constructor.
  1834       ///
  1835       /// Constructor for creating an id-to-item map.
  1836       explicit InverseMap(const Graph& graph) : _graph(&graph) {}
  1837 
  1838       /// \brief Constructor.
  1839       ///
  1840       /// Constructor for creating an id-to-item map.
  1841       explicit InverseMap(const IdMap& map) : _graph(map._graph) {}
  1842 
  1843       /// \brief Gives back the given item from its id.
  1844       ///
  1845       /// Gives back the given item from its id.
  1846       ///
  1847       Item operator[](int id) const { return _graph->fromId(id, Item());}
  1848 
  1849     private:
  1850       const Graph* _graph;
  1851     };
  1852 
  1853     /// \brief Gives back the inverse of the map.
  1854     ///
  1855     /// Gives back the inverse of the IdMap.
  1856     InverseMap inverse() const { return InverseMap(*_graph);}
  1857 
  1858   };
  1859 
  1860 
  1861   /// \brief General invertable graph-map type.
  1862 
  1863   /// This type provides simple invertable graph-maps.
  1864   /// The InvertableMap wraps an arbitrary ReadWriteMap
  1865   /// and if a key is set to a new value then store it
  1866   /// in the inverse map.
  1867   ///
  1868   /// The values of the map can be accessed
  1869   /// with stl compatible forward iterator.
  1870   ///
  1871   /// \tparam _Graph The graph type.
  1872   /// \tparam _Item The item type of the graph.
  1873   /// \tparam _Value The value type of the map.
  1874   ///
  1875   /// \see IterableValueMap
  1876   template <typename _Graph, typename _Item, typename _Value>
  1877   class InvertableMap
  1878     : protected ItemSetTraits<_Graph, _Item>::template Map<_Value>::Type {
  1879   private:
  1880 
  1881     typedef typename ItemSetTraits<_Graph, _Item>::
  1882     template Map<_Value>::Type Map;
  1883     typedef _Graph Graph;
  1884 
  1885     typedef std::map<_Value, _Item> Container;
  1886     Container _inv_map;
  1887 
  1888   public:
  1889 
  1890     /// The key type of InvertableMap (Node, Arc, Edge).
  1891     typedef typename Map::Key Key;
  1892     /// The value type of the InvertableMap.
  1893     typedef typename Map::Value Value;
  1894 
  1895     /// \brief Constructor.
  1896     ///
  1897     /// Construct a new InvertableMap for the graph.
  1898     ///
  1899     explicit InvertableMap(const Graph& graph) : Map(graph) {}
  1900 
  1901     /// \brief Forward iterator for values.
  1902     ///
  1903     /// This iterator is an stl compatible forward
  1904     /// iterator on the values of the map. The values can
  1905     /// be accessed in the [beginValue, endValue) range.
  1906     ///
  1907     class ValueIterator
  1908       : public std::iterator<std::forward_iterator_tag, Value> {
  1909       friend class InvertableMap;
  1910     private:
  1911       ValueIterator(typename Container::const_iterator _it)
  1912         : it(_it) {}
  1913     public:
  1914 
  1915       ValueIterator() {}
  1916 
  1917       ValueIterator& operator++() { ++it; return *this; }
  1918       ValueIterator operator++(int) {
  1919         ValueIterator tmp(*this);
  1920         operator++();
  1921         return tmp;
  1922       }
  1923 
  1924       const Value& operator*() const { return it->first; }
  1925       const Value* operator->() const { return &(it->first); }
  1926 
  1927       bool operator==(ValueIterator jt) const { return it == jt.it; }
  1928       bool operator!=(ValueIterator jt) const { return it != jt.it; }
  1929 
  1930     private:
  1931       typename Container::const_iterator it;
  1932     };
  1933 
  1934     /// \brief Returns an iterator to the first value.
  1935     ///
  1936     /// Returns an stl compatible iterator to the
  1937     /// first value of the map. The values of the
  1938     /// map can be accessed in the [beginValue, endValue)
  1939     /// range.
  1940     ValueIterator beginValue() const {
  1941       return ValueIterator(_inv_map.begin());
  1942     }
  1943 
  1944     /// \brief Returns an iterator after the last value.
  1945     ///
  1946     /// Returns an stl compatible iterator after the
  1947     /// last value of the map. The values of the
  1948     /// map can be accessed in the [beginValue, endValue)
  1949     /// range.
  1950     ValueIterator endValue() const {
  1951       return ValueIterator(_inv_map.end());
  1952     }
  1953 
  1954     /// \brief The setter function of the map.
  1955     ///
  1956     /// Sets the mapped value.
  1957     void set(const Key& key, const Value& val) {
  1958       Value oldval = Map::operator[](key);
  1959       typename Container::iterator it = _inv_map.find(oldval);
  1960       if (it != _inv_map.end() && it->second == key) {
  1961         _inv_map.erase(it);
  1962       }
  1963       _inv_map.insert(make_pair(val, key));
  1964       Map::set(key, val);
  1965     }
  1966 
  1967     /// \brief The getter function of the map.
  1968     ///
  1969     /// It gives back the value associated with the key.
  1970     typename MapTraits<Map>::ConstReturnValue
  1971     operator[](const Key& key) const {
  1972       return Map::operator[](key);
  1973     }
  1974 
  1975     /// \brief Gives back the item by its value.
  1976     ///
  1977     /// Gives back the item by its value.
  1978     Key operator()(const Value& key) const {
  1979       typename Container::const_iterator it = _inv_map.find(key);
  1980       return it != _inv_map.end() ? it->second : INVALID;
  1981     }
  1982 
  1983   protected:
  1984 
  1985     /// \brief Erase the key from the map.
  1986     ///
  1987     /// Erase the key to the map. It is called by the
  1988     /// \c AlterationNotifier.
  1989     virtual void erase(const Key& key) {
  1990       Value val = Map::operator[](key);
  1991       typename Container::iterator it = _inv_map.find(val);
  1992       if (it != _inv_map.end() && it->second == key) {
  1993         _inv_map.erase(it);
  1994       }
  1995       Map::erase(key);
  1996     }
  1997 
  1998     /// \brief Erase more keys from the map.
  1999     ///
  2000     /// Erase more keys from the map. It is called by the
  2001     /// \c AlterationNotifier.
  2002     virtual void erase(const std::vector<Key>& keys) {
  2003       for (int i = 0; i < int(keys.size()); ++i) {
  2004         Value val = Map::operator[](keys[i]);
  2005         typename Container::iterator it = _inv_map.find(val);
  2006         if (it != _inv_map.end() && it->second == keys[i]) {
  2007           _inv_map.erase(it);
  2008         }
  2009       }
  2010       Map::erase(keys);
  2011     }
  2012 
  2013     /// \brief Clear the keys from the map and inverse map.
  2014     ///
  2015     /// Clear the keys from the map and inverse map. It is called by the
  2016     /// \c AlterationNotifier.
  2017     virtual void clear() {
  2018       _inv_map.clear();
  2019       Map::clear();
  2020     }
  2021 
  2022   public:
  2023 
  2024     /// \brief The inverse map type.
  2025     ///
  2026     /// The inverse of this map. The subscript operator of the map
  2027     /// gives back always the item what was last assigned to the value.
  2028     class InverseMap {
  2029     public:
  2030       /// \brief Constructor of the InverseMap.
  2031       ///
  2032       /// Constructor of the InverseMap.
  2033       explicit InverseMap(const InvertableMap& inverted)
  2034         : _inverted(inverted) {}
  2035 
  2036       /// The value type of the InverseMap.
  2037       typedef typename InvertableMap::Key Value;
  2038       /// The key type of the InverseMap.
  2039       typedef typename InvertableMap::Value Key;
  2040 
  2041       /// \brief Subscript operator.
  2042       ///
  2043       /// Subscript operator. It gives back always the item
  2044       /// what was last assigned to the value.
  2045       Value operator[](const Key& key) const {
  2046         return _inverted(key);
  2047       }
  2048 
  2049     private:
  2050       const InvertableMap& _inverted;
  2051     };
  2052 
  2053     /// \brief It gives back the just readable inverse map.
  2054     ///
  2055     /// It gives back the just readable inverse map.
  2056     InverseMap inverse() const {
  2057       return InverseMap(*this);
  2058     }
  2059 
  2060   };
  2061 
  2062   /// \brief Provides a mutable, continuous and unique descriptor for each
  2063   /// item in the graph.
  2064   ///
  2065   /// The DescriptorMap class provides a unique and continuous (but mutable)
  2066   /// descriptor (id) for each item of the same type (e.g. node) in the
  2067   /// graph. This id is <ul><li>\b unique: different items (nodes) get
  2068   /// different ids <li>\b continuous: the range of the ids is the set of
  2069   /// integers between 0 and \c n-1, where \c n is the number of the items of
  2070   /// this type (e.g. nodes) (so the id of a node can change if you delete an
  2071   /// other node, i.e. this id is mutable).  </ul> This map can be inverted
  2072   /// with its member class \c InverseMap, or with the \c operator() member.
  2073   ///
  2074   /// \tparam _Graph The graph class the \c DescriptorMap belongs to.
  2075   /// \tparam _Item The Item is the Key of the Map. It may be Node, Arc or
  2076   /// Edge.
  2077   template <typename _Graph, typename _Item>
  2078   class DescriptorMap
  2079     : protected ItemSetTraits<_Graph, _Item>::template Map<int>::Type {
  2080 
  2081     typedef _Item Item;
  2082     typedef typename ItemSetTraits<_Graph, _Item>::template Map<int>::Type Map;
  2083 
  2084   public:
  2085     /// The graph class of DescriptorMap.
  2086     typedef _Graph Graph;
  2087 
  2088     /// The key type of DescriptorMap (Node, Arc, Edge).
  2089     typedef typename Map::Key Key;
  2090     /// The value type of DescriptorMap.
  2091     typedef typename Map::Value Value;
  2092 
  2093     /// \brief Constructor.
  2094     ///
  2095     /// Constructor for descriptor map.
  2096     explicit DescriptorMap(const Graph& _graph) : Map(_graph) {
  2097       Item it;
  2098       const typename Map::Notifier* nf = Map::notifier();
  2099       for (nf->first(it); it != INVALID; nf->next(it)) {
  2100         Map::set(it, _inv_map.size());
  2101         _inv_map.push_back(it);
  2102       }
  2103     }
  2104 
  2105   protected:
  2106 
  2107     /// \brief Add a new key to the map.
  2108     ///
  2109     /// Add a new key to the map. It is called by the
  2110     /// \c AlterationNotifier.
  2111     virtual void add(const Item& item) {
  2112       Map::add(item);
  2113       Map::set(item, _inv_map.size());
  2114       _inv_map.push_back(item);
  2115     }
  2116 
  2117     /// \brief Add more new keys to the map.
  2118     ///
  2119     /// Add more new keys to the map. It is called by the
  2120     /// \c AlterationNotifier.
  2121     virtual void add(const std::vector<Item>& items) {
  2122       Map::add(items);
  2123       for (int i = 0; i < int(items.size()); ++i) {
  2124         Map::set(items[i], _inv_map.size());
  2125         _inv_map.push_back(items[i]);
  2126       }
  2127     }
  2128 
  2129     /// \brief Erase the key from the map.
  2130     ///
  2131     /// Erase the key from the map. It is called by the
  2132     /// \c AlterationNotifier.
  2133     virtual void erase(const Item& item) {
  2134       Map::set(_inv_map.back(), Map::operator[](item));
  2135       _inv_map[Map::operator[](item)] = _inv_map.back();
  2136       _inv_map.pop_back();
  2137       Map::erase(item);
  2138     }
  2139 
  2140     /// \brief Erase more keys from the map.
  2141     ///
  2142     /// Erase more keys from the map. It is called by the
  2143     /// \c AlterationNotifier.
  2144     virtual void erase(const std::vector<Item>& items) {
  2145       for (int i = 0; i < int(items.size()); ++i) {
  2146         Map::set(_inv_map.back(), Map::operator[](items[i]));
  2147         _inv_map[Map::operator[](items[i])] = _inv_map.back();
  2148         _inv_map.pop_back();
  2149       }
  2150       Map::erase(items);
  2151     }
  2152 
  2153     /// \brief Build the unique map.
  2154     ///
  2155     /// Build the unique map. It is called by the
  2156     /// \c AlterationNotifier.
  2157     virtual void build() {
  2158       Map::build();
  2159       Item it;
  2160       const typename Map::Notifier* nf = Map::notifier();
  2161       for (nf->first(it); it != INVALID; nf->next(it)) {
  2162         Map::set(it, _inv_map.size());
  2163         _inv_map.push_back(it);
  2164       }
  2165     }
  2166 
  2167     /// \brief Clear the keys from the map.
  2168     ///
  2169     /// Clear the keys from the map. It is called by the
  2170     /// \c AlterationNotifier.
  2171     virtual void clear() {
  2172       _inv_map.clear();
  2173       Map::clear();
  2174     }
  2175 
  2176   public:
  2177 
  2178     /// \brief Returns the maximal value plus one.
  2179     ///
  2180     /// Returns the maximal value plus one in the map.
  2181     unsigned int size() const {
  2182       return _inv_map.size();
  2183     }
  2184 
  2185     /// \brief Swaps the position of the two items in the map.
  2186     ///
  2187     /// Swaps the position of the two items in the map.
  2188     void swap(const Item& p, const Item& q) {
  2189       int pi = Map::operator[](p);
  2190       int qi = Map::operator[](q);
  2191       Map::set(p, qi);
  2192       _inv_map[qi] = p;
  2193       Map::set(q, pi);
  2194       _inv_map[pi] = q;
  2195     }
  2196 
  2197     /// \brief Gives back the \e descriptor of the item.
  2198     ///
  2199     /// Gives back the mutable and unique \e descriptor of the map.
  2200     int operator[](const Item& item) const {
  2201       return Map::operator[](item);
  2202     }
  2203 
  2204     /// \brief Gives back the item by its descriptor.
  2205     ///
  2206     /// Gives back th item by its descriptor.
  2207     Item operator()(int id) const {
  2208       return _inv_map[id];
  2209     }
  2210 
  2211   private:
  2212 
  2213     typedef std::vector<Item> Container;
  2214     Container _inv_map;
  2215 
  2216   public:
  2217     /// \brief The inverse map type of DescriptorMap.
  2218     ///
  2219     /// The inverse map type of DescriptorMap.
  2220     class InverseMap {
  2221     public:
  2222       /// \brief Constructor of the InverseMap.
  2223       ///
  2224       /// Constructor of the InverseMap.
  2225       explicit InverseMap(const DescriptorMap& inverted)
  2226         : _inverted(inverted) {}
  2227 
  2228 
  2229       /// The value type of the InverseMap.
  2230       typedef typename DescriptorMap::Key Value;
  2231       /// The key type of the InverseMap.
  2232       typedef typename DescriptorMap::Value Key;
  2233 
  2234       /// \brief Subscript operator.
  2235       ///
  2236       /// Subscript operator. It gives back the item
  2237       /// that the descriptor belongs to currently.
  2238       Value operator[](const Key& key) const {
  2239         return _inverted(key);
  2240       }
  2241 
  2242       /// \brief Size of the map.
  2243       ///
  2244       /// Returns the size of the map.
  2245       unsigned int size() const {
  2246         return _inverted.size();
  2247       }
  2248 
  2249     private:
  2250       const DescriptorMap& _inverted;
  2251     };
  2252 
  2253     /// \brief Gives back the inverse of the map.
  2254     ///
  2255     /// Gives back the inverse of the map.
  2256     const InverseMap inverse() const {
  2257       return InverseMap(*this);
  2258     }
  2259   };
  2260 
  2261   /// \brief Returns the source of the given arc.
  2262   ///
  2263   /// The SourceMap gives back the source Node of the given arc.
  2264   /// \see TargetMap
  2265   template <typename Digraph>
  2266   class SourceMap {
  2267   public:
  2268 
  2269     typedef typename Digraph::Node Value;
  2270     typedef typename Digraph::Arc Key;
  2271 
  2272     /// \brief Constructor
  2273     ///
  2274     /// Constructor
  2275     /// \param digraph The digraph that the map belongs to.
  2276     explicit SourceMap(const Digraph& digraph) : _digraph(digraph) {}
  2277 
  2278     /// \brief The subscript operator.
  2279     ///
  2280     /// The subscript operator.
  2281     /// \param arc The arc
  2282     /// \return The source of the arc
  2283     Value operator[](const Key& arc) const {
  2284       return _digraph.source(arc);
  2285     }
  2286 
  2287   private:
  2288     const Digraph& _digraph;
  2289   };
  2290 
  2291   /// \brief Returns a \c SourceMap class.
  2292   ///
  2293   /// This function just returns an \c SourceMap class.
  2294   /// \relates SourceMap
  2295   template <typename Digraph>
  2296   inline SourceMap<Digraph> sourceMap(const Digraph& digraph) {
  2297     return SourceMap<Digraph>(digraph);
  2298   }
  2299 
  2300   /// \brief Returns the target of the given arc.
  2301   ///
  2302   /// The TargetMap gives back the target Node of the given arc.
  2303   /// \see SourceMap
  2304   template <typename Digraph>
  2305   class TargetMap {
  2306   public:
  2307 
  2308     typedef typename Digraph::Node Value;
  2309     typedef typename Digraph::Arc Key;
  2310 
  2311     /// \brief Constructor
  2312     ///
  2313     /// Constructor
  2314     /// \param digraph The digraph that the map belongs to.
  2315     explicit TargetMap(const Digraph& digraph) : _digraph(digraph) {}
  2316 
  2317     /// \brief The subscript operator.
  2318     ///
  2319     /// The subscript operator.
  2320     /// \param e The arc
  2321     /// \return The target of the arc
  2322     Value operator[](const Key& e) const {
  2323       return _digraph.target(e);
  2324     }
  2325 
  2326   private:
  2327     const Digraph& _digraph;
  2328   };
  2329 
  2330   /// \brief Returns a \c TargetMap class.
  2331   ///
  2332   /// This function just returns a \c TargetMap class.
  2333   /// \relates TargetMap
  2334   template <typename Digraph>
  2335   inline TargetMap<Digraph> targetMap(const Digraph& digraph) {
  2336     return TargetMap<Digraph>(digraph);
  2337   }
  2338 
  2339   /// \brief Returns the "forward" directed arc view of an edge.
  2340   ///
  2341   /// Returns the "forward" directed arc view of an edge.
  2342   /// \see BackwardMap
  2343   template <typename Graph>
  2344   class ForwardMap {
  2345   public:
  2346 
  2347     typedef typename Graph::Arc Value;
  2348     typedef typename Graph::Edge Key;
  2349 
  2350     /// \brief Constructor
  2351     ///
  2352     /// Constructor
  2353     /// \param graph The graph that the map belongs to.
  2354     explicit ForwardMap(const Graph& graph) : _graph(graph) {}
  2355 
  2356     /// \brief The subscript operator.
  2357     ///
  2358     /// The subscript operator.
  2359     /// \param key An edge
  2360     /// \return The "forward" directed arc view of edge
  2361     Value operator[](const Key& key) const {
  2362       return _graph.direct(key, true);
  2363     }
  2364 
  2365   private:
  2366     const Graph& _graph;
  2367   };
  2368 
  2369   /// \brief Returns a \c ForwardMap class.
  2370   ///
  2371   /// This function just returns an \c ForwardMap class.
  2372   /// \relates ForwardMap
  2373   template <typename Graph>
  2374   inline ForwardMap<Graph> forwardMap(const Graph& graph) {
  2375     return ForwardMap<Graph>(graph);
  2376   }
  2377 
  2378   /// \brief Returns the "backward" directed arc view of an edge.
  2379   ///
  2380   /// Returns the "backward" directed arc view of an edge.
  2381   /// \see ForwardMap
  2382   template <typename Graph>
  2383   class BackwardMap {
  2384   public:
  2385 
  2386     typedef typename Graph::Arc Value;
  2387     typedef typename Graph::Edge Key;
  2388 
  2389     /// \brief Constructor
  2390     ///
  2391     /// Constructor
  2392     /// \param graph The graph that the map belongs to.
  2393     explicit BackwardMap(const Graph& graph) : _graph(graph) {}
  2394 
  2395     /// \brief The subscript operator.
  2396     ///
  2397     /// The subscript operator.
  2398     /// \param key An edge
  2399     /// \return The "backward" directed arc view of edge
  2400     Value operator[](const Key& key) const {
  2401       return _graph.direct(key, false);
  2402     }
  2403 
  2404   private:
  2405     const Graph& _graph;
  2406   };
  2407 
  2408   /// \brief Returns a \c BackwardMap class
  2409 
  2410   /// This function just returns a \c BackwardMap class.
  2411   /// \relates BackwardMap
  2412   template <typename Graph>
  2413   inline BackwardMap<Graph> backwardMap(const Graph& graph) {
  2414     return BackwardMap<Graph>(graph);
  2415   }
  2416 
  2417   /// \brief Potential difference map
  2418   ///
  2419   /// If there is an potential map on the nodes then we
  2420   /// can get an arc map as we get the substraction of the
  2421   /// values of the target and source.
  2422   template <typename Digraph, typename NodeMap>
  2423   class PotentialDifferenceMap {
  2424   public:
  2425     typedef typename Digraph::Arc Key;
  2426     typedef typename NodeMap::Value Value;
  2427 
  2428     /// \brief Constructor
  2429     ///
  2430     /// Contructor of the map
  2431     explicit PotentialDifferenceMap(const Digraph& digraph,
  2432                                     const NodeMap& potential)
  2433       : _digraph(digraph), _potential(potential) {}
  2434 
  2435     /// \brief Const subscription operator
  2436     ///
  2437     /// Const subscription operator
  2438     Value operator[](const Key& arc) const {
  2439       return _potential[_digraph.target(arc)] -
  2440         _potential[_digraph.source(arc)];
  2441     }
  2442 
  2443   private:
  2444     const Digraph& _digraph;
  2445     const NodeMap& _potential;
  2446   };
  2447 
  2448   /// \brief Returns a PotentialDifferenceMap.
  2449   ///
  2450   /// This function just returns a PotentialDifferenceMap.
  2451   /// \relates PotentialDifferenceMap
  2452   template <typename Digraph, typename NodeMap>
  2453   PotentialDifferenceMap<Digraph, NodeMap>
  2454   potentialDifferenceMap(const Digraph& digraph, const NodeMap& potential) {
  2455     return PotentialDifferenceMap<Digraph, NodeMap>(digraph, potential);
  2456   }
  2457 
  2458   /// \brief Map of the node in-degrees.
  2459   ///
  2460   /// This map returns the in-degree of a node. Once it is constructed,
  2461   /// the degrees are stored in a standard NodeMap, so each query is done
  2462   /// in constant time. On the other hand, the values are updated automatically
  2463   /// whenever the digraph changes.
  2464   ///
  2465   /// \warning Besides addNode() and addArc(), a digraph structure may provide
  2466   /// alternative ways to modify the digraph. The correct behavior of InDegMap
  2467   /// is not guarantied if these additional features are used. For example
  2468   /// the functions \ref ListDigraph::changeSource() "changeSource()",
  2469   /// \ref ListDigraph::changeTarget() "changeTarget()" and
  2470   /// \ref ListDigraph::reverseArc() "reverseArc()"
  2471   /// of \ref ListDigraph will \e not update the degree values correctly.
  2472   ///
  2473   /// \sa OutDegMap
  2474 
  2475   template <typename _Digraph>
  2476   class InDegMap
  2477     : protected ItemSetTraits<_Digraph, typename _Digraph::Arc>
  2478       ::ItemNotifier::ObserverBase {
  2479 
  2480   public:
  2481 
  2482     typedef _Digraph Digraph;
  2483     typedef int Value;
  2484     typedef typename Digraph::Node Key;
  2485 
  2486     typedef typename ItemSetTraits<Digraph, typename Digraph::Arc>
  2487     ::ItemNotifier::ObserverBase Parent;
  2488 
  2489   private:
  2490 
  2491     class AutoNodeMap
  2492       : public ItemSetTraits<Digraph, Key>::template Map<int>::Type {
  2493     public:
  2494 
  2495       typedef typename ItemSetTraits<Digraph, Key>::
  2496       template Map<int>::Type Parent;
  2497 
  2498       AutoNodeMap(const Digraph& digraph) : Parent(digraph, 0) {}
  2499 
  2500       virtual void add(const Key& key) {
  2501         Parent::add(key);
  2502         Parent::set(key, 0);
  2503       }
  2504 
  2505       virtual void add(const std::vector<Key>& keys) {
  2506         Parent::add(keys);
  2507         for (int i = 0; i < int(keys.size()); ++i) {
  2508           Parent::set(keys[i], 0);
  2509         }
  2510       }
  2511 
  2512       virtual void build() {
  2513         Parent::build();
  2514         Key it;
  2515         typename Parent::Notifier* nf = Parent::notifier();
  2516         for (nf->first(it); it != INVALID; nf->next(it)) {
  2517           Parent::set(it, 0);
  2518         }
  2519       }
  2520     };
  2521 
  2522   public:
  2523 
  2524     /// \brief Constructor.
  2525     ///
  2526     /// Constructor for creating in-degree map.
  2527     explicit InDegMap(const Digraph& digraph)
  2528       : _digraph(digraph), _deg(digraph) {
  2529       Parent::attach(_digraph.notifier(typename Digraph::Arc()));
  2530 
  2531       for(typename Digraph::NodeIt it(_digraph); it != INVALID; ++it) {
  2532         _deg[it] = countInArcs(_digraph, it);
  2533       }
  2534     }
  2535 
  2536     /// Gives back the in-degree of a Node.
  2537     int operator[](const Key& key) const {
  2538       return _deg[key];
  2539     }
  2540 
  2541   protected:
  2542 
  2543     typedef typename Digraph::Arc Arc;
  2544 
  2545     virtual void add(const Arc& arc) {
  2546       ++_deg[_digraph.target(arc)];
  2547     }
  2548 
  2549     virtual void add(const std::vector<Arc>& arcs) {
  2550       for (int i = 0; i < int(arcs.size()); ++i) {
  2551         ++_deg[_digraph.target(arcs[i])];
  2552       }
  2553     }
  2554 
  2555     virtual void erase(const Arc& arc) {
  2556       --_deg[_digraph.target(arc)];
  2557     }
  2558 
  2559     virtual void erase(const std::vector<Arc>& arcs) {
  2560       for (int i = 0; i < int(arcs.size()); ++i) {
  2561         --_deg[_digraph.target(arcs[i])];
  2562       }
  2563     }
  2564 
  2565     virtual void build() {
  2566       for(typename Digraph::NodeIt it(_digraph); it != INVALID; ++it) {
  2567         _deg[it] = countInArcs(_digraph, it);
  2568       }
  2569     }
  2570 
  2571     virtual void clear() {
  2572       for(typename Digraph::NodeIt it(_digraph); it != INVALID; ++it) {
  2573         _deg[it] = 0;
  2574       }
  2575     }
  2576   private:
  2577 
  2578     const Digraph& _digraph;
  2579     AutoNodeMap _deg;
  2580   };
  2581 
  2582   /// \brief Map of the node out-degrees.
  2583   ///
  2584   /// This map returns the out-degree of a node. Once it is constructed,
  2585   /// the degrees are stored in a standard NodeMap, so each query is done
  2586   /// in constant time. On the other hand, the values are updated automatically
  2587   /// whenever the digraph changes.
  2588   ///
  2589   /// \warning Besides addNode() and addArc(), a digraph structure may provide
  2590   /// alternative ways to modify the digraph. The correct behavior of OutDegMap
  2591   /// is not guarantied if these additional features are used. For example
  2592   /// the functions \ref ListDigraph::changeSource() "changeSource()",
  2593   /// \ref ListDigraph::changeTarget() "changeTarget()" and
  2594   /// \ref ListDigraph::reverseArc() "reverseArc()"
  2595   /// of \ref ListDigraph will \e not update the degree values correctly.
  2596   ///
  2597   /// \sa InDegMap
  2598 
  2599   template <typename _Digraph>
  2600   class OutDegMap
  2601     : protected ItemSetTraits<_Digraph, typename _Digraph::Arc>
  2602       ::ItemNotifier::ObserverBase {
  2603 
  2604   public:
  2605 
  2606     typedef _Digraph Digraph;
  2607     typedef int Value;
  2608     typedef typename Digraph::Node Key;
  2609 
  2610     typedef typename ItemSetTraits<Digraph, typename Digraph::Arc>
  2611     ::ItemNotifier::ObserverBase Parent;
  2612 
  2613   private:
  2614 
  2615     class AutoNodeMap
  2616       : public ItemSetTraits<Digraph, Key>::template Map<int>::Type {
  2617     public:
  2618 
  2619       typedef typename ItemSetTraits<Digraph, Key>::
  2620       template Map<int>::Type Parent;
  2621 
  2622       AutoNodeMap(const Digraph& digraph) : Parent(digraph, 0) {}
  2623 
  2624       virtual void add(const Key& key) {
  2625         Parent::add(key);
  2626         Parent::set(key, 0);
  2627       }
  2628       virtual void add(const std::vector<Key>& keys) {
  2629         Parent::add(keys);
  2630         for (int i = 0; i < int(keys.size()); ++i) {
  2631           Parent::set(keys[i], 0);
  2632         }
  2633       }
  2634       virtual void build() {
  2635         Parent::build();
  2636         Key it;
  2637         typename Parent::Notifier* nf = Parent::notifier();
  2638         for (nf->first(it); it != INVALID; nf->next(it)) {
  2639           Parent::set(it, 0);
  2640         }
  2641       }
  2642     };
  2643 
  2644   public:
  2645 
  2646     /// \brief Constructor.
  2647     ///
  2648     /// Constructor for creating out-degree map.
  2649     explicit OutDegMap(const Digraph& digraph)
  2650       : _digraph(digraph), _deg(digraph) {
  2651       Parent::attach(_digraph.notifier(typename Digraph::Arc()));
  2652 
  2653       for(typename Digraph::NodeIt it(_digraph); it != INVALID; ++it) {
  2654         _deg[it] = countOutArcs(_digraph, it);
  2655       }
  2656     }
  2657 
  2658     /// Gives back the out-degree of a Node.
  2659     int operator[](const Key& key) const {
  2660       return _deg[key];
  2661     }
  2662 
  2663   protected:
  2664 
  2665     typedef typename Digraph::Arc Arc;
  2666 
  2667     virtual void add(const Arc& arc) {
  2668       ++_deg[_digraph.source(arc)];
  2669     }
  2670 
  2671     virtual void add(const std::vector<Arc>& arcs) {
  2672       for (int i = 0; i < int(arcs.size()); ++i) {
  2673         ++_deg[_digraph.source(arcs[i])];
  2674       }
  2675     }
  2676 
  2677     virtual void erase(const Arc& arc) {
  2678       --_deg[_digraph.source(arc)];
  2679     }
  2680 
  2681     virtual void erase(const std::vector<Arc>& arcs) {
  2682       for (int i = 0; i < int(arcs.size()); ++i) {
  2683         --_deg[_digraph.source(arcs[i])];
  2684       }
  2685     }
  2686 
  2687     virtual void build() {
  2688       for(typename Digraph::NodeIt it(_digraph); it != INVALID; ++it) {
  2689         _deg[it] = countOutArcs(_digraph, it);
  2690       }
  2691     }
  2692 
  2693     virtual void clear() {
  2694       for(typename Digraph::NodeIt it(_digraph); it != INVALID; ++it) {
  2695         _deg[it] = 0;
  2696       }
  2697     }
  2698   private:
  2699 
  2700     const Digraph& _digraph;
  2701     AutoNodeMap _deg;
  2702   };
  2703 
  2704   /// @}
  2705 }
  2706 
  2707 #endif // LEMON_MAPS_H