/* -*- mode: C++; indent-tabs-mode: nil; -*-

  *

  * This file is a part of LEMON, a generic C++ optimization library.

  *

  * Copyright (C) 2003-2008

  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * (Egervary Research Group on Combinatorial Optimization, EGRES).

  *

  * Permission to use, modify and distribute this software is granted

  * provided that this copyright notice appears in all copies. For

  * precise terms see the accompanying LICENSE file.

  *

  * This software is provided "AS IS" with no warranty of any kind,

  * express or implied, and with no claim as to its suitability for any

  * purpose.

  *

  */

 #ifndef HYPERCUBE_GRAPH_H

 #define HYPERCUBE_GRAPH_H

 #include <iostream>

 #include <vector>

 #include <lemon/core.h>

 #include <lemon/error.h>

 #include <lemon/bits/base_extender.h>

 #include <lemon/bits/graph_extender.h>

 ///\ingroup graphs

 ///\file

 ///\brief HypercubeDigraph class.

 namespace lemon {

   class HypercubeDigraphBase {

   public:

     typedef HypercubeDigraphBase Digraph;

     class Node;

     class Arc;

   public:

     HypercubeDigraphBase() {}

   protected:

     void construct(int dim) {

       _dim = dim;

       _nodeNum = 1 << dim;

     }

   public:

     typedef True NodeNumTag;

     typedef True ArcNumTag;

     int nodeNum() const { return _nodeNum; }

     int arcNum() const { return _nodeNum * _dim; }

     int maxNodeId() const { return nodeNum() - 1; }

     int maxArcId() const { return arcNum() - 1; }

     Node source(Arc e) const {

       return e.id / _dim;

     }

     Node target(Arc e) const {

       return (e.id / _dim) ^ (1 << (e.id % _dim));

     }

     static int id(Node v) { return v.id; }

     static int id(Arc e) { return e.id; }

     static Node nodeFromId(int id) { return Node(id); }

     static Arc arcFromId(int id) { return Arc(id); }

     class Node {

       friend class HypercubeDigraphBase;

     protected:

       int id;

       Node(int _id) { id = _id;}

     public:

       Node() {}

       Node (Invalid) { id = -1; }

       bool operator==(const Node node) const { return id == node.id; }

       bool operator!=(const Node node) const { return id != node.id; }

       bool operator<(const Node node) const { return id < node.id; }

     };

     class Arc {

       friend class HypercubeDigraphBase;

     protected:

       int id;

       Arc(int _id) : id(_id) {}

     public:

       Arc() { }

       Arc (Invalid) { id = -1; }

       bool operator==(const Arc arc) const { return id == arc.id; }

       bool operator!=(const Arc arc) const { return id != arc.id; }

       bool operator<(const Arc arc) const { return id < arc.id; }

     };

     void first(Node& node) const {

       node.id = nodeNum() - 1;

     }

     static void next(Node& node) {

       --node.id;

     }

     void first(Arc& arc) const {

       arc.id = arcNum() - 1;

     }

     static void next(Arc& arc) {

       --arc.id;

     }

     void firstOut(Arc& arc, const Node& node) const {

       arc.id = node.id * _dim;

     }

     void nextOut(Arc& arc) const {

       ++arc.id;

       if (arc.id % _dim == 0) arc.id = -1;

     }

     void firstIn(Arc& arc, const Node& node) const {

       arc.id = (node.id ^ 1) * _dim;

     }

     void nextIn(Arc& arc) const {

       int cnt = arc.id % _dim;

       if ((cnt + 1) % _dim == 0) {

         arc.id = -1;

       } else {

         arc.id = ((arc.id / _dim) ^ ((1 << cnt) * 3)) * _dim + cnt + 1;

       }

     }

     int dimension() const {

       return _dim;

     }

     bool projection(Node node, int n) const {

       return static_cast<bool>(node.id & (1 << n));

     }

     int dimension(Arc arc) const {

       return arc.id % _dim;

     }

     int index(Node node) const {

       return node.id;

     }

     Node operator()(int ix) const {

       return Node(ix);

     }

   private:

     int _dim, _nodeNum;

   };

   typedef DigraphExtender<HypercubeDigraphBase> ExtendedHypercubeDigraphBase;

   /// \ingroup digraphs

   ///

   /// \brief Hypercube digraph class

   ///

   /// This class implements a special digraph type. The nodes of the

   /// digraph are indiced with integers with at most \c dim binary digits.

   /// Two nodes are connected in the digraph if the indices differ only

   /// on one position in the binary form.

   ///

   /// \note The type of the \c ids is chosen to \c int because efficiency

   /// reasons. Thus the maximum dimension of this implementation is 26.

   ///

   /// The digraph type is fully conform to the \ref concepts::Digraph

   /// concept but it does not conform to \ref concepts::Graph.

   class HypercubeDigraph : public ExtendedHypercubeDigraphBase {

   public:

     typedef ExtendedHypercubeDigraphBase Parent;

     /// \brief Construct a hypercube digraph with \c dim dimension.

     ///

     /// Construct a hypercube digraph with \c dim dimension.

     HypercubeDigraph(int dim) { construct(dim); }

     /// \brief Gives back the number of the dimensions.

     ///

     /// Gives back the number of the dimensions.

     int dimension() const {

       return Parent::dimension();

     }

     /// \brief Returns true if the n'th bit of the node is one.

     ///

     /// Returns true if the n'th bit of the node is one.

     bool projection(Node node, int n) const {

       return Parent::projection(node, n);

     }

     /// \brief The dimension id of the arc.

     ///

     /// It returns the dimension id of the arc. It can

     /// be in the \f$ \{0, 1, \dots, dim-1\} \f$ interval.

     int dimension(Arc arc) const {

       return Parent::dimension(arc);

     }

     /// \brief Gives back the index of the node.

     ///

     /// Gives back the index of the node. The lower bits of the

     /// integer describes the node.

     int index(Node node) const {

       return Parent::index(node);

     }

     /// \brief Gives back the node by its index.

     ///

     /// Gives back the node by its index.

     Node operator()(int ix) const {

       return Parent::operator()(ix);

     }

     /// \brief Number of nodes.

     int nodeNum() const { return Parent::nodeNum(); }

     /// \brief Number of arcs.

     int arcNum() const { return Parent::arcNum(); }

     /// \brief Linear combination map.

     ///

     /// It makes possible to give back a linear combination

     /// for each node. This function works like the \c std::accumulate

     /// so it accumulates the \c bf binary function with the \c fv

     /// first value. The map accumulates only on that dimensions where

     /// the node's index is one. The accumulated values should be

     /// given by the \c begin and \c end iterators and the length of this

     /// range should be equal to the dimension number of the digraph.

     ///

     ///\code

     /// const int DIM = 3;

     /// HypercubeDigraph digraph(DIM);

     /// dim2::Point<double> base[DIM];

     /// for (int k = 0; k < DIM; ++k) {

     ///   base[k].x = rnd();

     ///   base[k].y = rnd();

     /// }

     /// HypercubeDigraph::HyperMap<dim2::Point<double> >

     ///   pos(digraph, base, base + DIM, dim2::Point<double>(0.0, 0.0));

     ///\endcode

     ///

     /// \see HypercubeDigraph

     template <typename T, typename BF = std::plus<T> >

     class HyperMap {

     public:

       typedef Node Key;

       typedef T Value;

       /// \brief Constructor for HyperMap.

       ///

       /// Construct a HyperMap for the given digraph. The accumulated values

       /// should be given by the \c begin and \c end iterators and the length

       /// of this range should be equal to the dimension number of the digraph.

       ///

       /// This function accumulates the \c bf binary function with

       /// the \c fv first value. The map accumulates only on that dimensions

       /// where the node's index is one.

       template <typename It>

       HyperMap(const Digraph& digraph, It begin, It end,

                T fv = 0.0, const BF& bf = BF())

         : _graph(digraph), _values(begin, end), _first_value(fv), _bin_func(bf)

       {

         LEMON_ASSERT(_values.size() == digraph.dimension(),

                      "Wrong size of dimension");

       }

       /// \brief Gives back the partial accumulated value.

       ///

       /// Gives back the partial accumulated value.

       Value operator[](Key k) const {

         Value val = _first_value;

         int id = _graph.index(k);

         int n = 0;

         while (id != 0) {

           if (id & 1) {

             val = _bin_func(val, _values[n]);

           }

           id >>= 1;

           ++n;

         }

         return val;

       }

     private:

       const Digraph& _graph;

       std::vector<T> _values;

       T _first_value;

       BF _bin_func;

     };

   };

 }

 #endif