RhodeCode

/* -*- 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 LEMON_DIJKSTRA_H

#define LEMON_DIJKSTRA_H

///\ingroup shortest_path

///\file

///\brief Dijkstra algorithm.

#include <limits>

#include <lemon/list_graph.h>

#include <lemon/bin_heap.h>

#include <lemon/bits/path_dump.h>

#include <lemon/core.h>

#include <lemon/error.h>

#include <lemon/maps.h>

#include <lemon/path.h>

namespace lemon {

  /// \brief Default operation traits for the Dijkstra algorithm class.

  ///

  /// This operation traits class defines all computational operations and

  /// constants which are used in the Dijkstra algorithm.

  template <typename Value>

  struct DijkstraDefaultOperationTraits {

    /// \brief Gives back the zero value of the type.

    static Value zero() {

      return static_cast<Value>(0);

    }

    /// \brief Gives back the sum of the given two elements.

    static Value plus(const Value& left, const Value& right) {

      return left + right;

    }

    /// \brief Gives back true only if the first value is less than the second.

    static bool less(const Value& left, const Value& right) {

      return left < right;

    }

  };

  ///Default traits class of Dijkstra class.

  ///Default traits class of Dijkstra class.

  ///\tparam GR The type of the digraph.

  ///\tparam LM The type of the length map.

  template<class GR, class LM>

  struct DijkstraDefaultTraits

  {

    ///The type of the digraph the algorithm runs on.

    typedef GR Digraph;

    ///The type of the map that stores the arc lengths.

    ///The type of the map that stores the arc lengths.

    ///It must meet the \ref concepts::ReadMap "ReadMap" concept.

    typedef LM LengthMap;

    ///The type of the length of the arcs.

    typedef typename LM::Value Value;

    /// Operation traits for Dijkstra algorithm.

    /// This class defines the operations that are used in the algorithm.

    /// \see DijkstraDefaultOperationTraits

    typedef DijkstraDefaultOperationTraits<Value> OperationTraits;

    /// The cross reference type used by the heap.

    /// The cross reference type used by the heap.

    /// Usually it is \c Digraph::NodeMap<int>.

    typedef typename Digraph::template NodeMap<int> HeapCrossRef;

    ///Instantiates a \ref HeapCrossRef.

    ///This function instantiates a \ref HeapCrossRef.

    /// \param g is the digraph, to which we would like to define the

    /// \ref HeapCrossRef.

    static HeapCrossRef *createHeapCrossRef(const Digraph &g)

    {

      return new HeapCrossRef(g);

    }

    ///The heap type used by the Dijkstra algorithm.

    ///The heap type used by the Dijkstra algorithm.

    ///

    ///\sa BinHeap

    ///\sa Dijkstra

    typedef BinHeap<typename LM::Value, HeapCrossRef, std::less<Value> > Heap;

    ///Instantiates a \ref Heap.

    ///This function instantiates a \ref Heap.

    static Heap *createHeap(HeapCrossRef& r)

    {

      return new Heap(r);

    }

    ///\brief The type of the map that stores the predecessor

    ///arcs of the shortest paths.

    ///

    ///The type of the map that stores the predecessor

    ///arcs of the shortest paths.

    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.

    typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap;

    ///Instantiates a PredMap.

#include "test_tools.h"

using namespace lemon;

char test_lgf[] =

  "@nodes\n"

  "label\n"

  "0\n"

  "1\n"

  "2\n"

  "3\n"

  "4\n"

  "@arcs\n"

  "     label length\n"

  "0 1  0     1\n"

  "1 2  1     1\n"

  "2 3  2     1\n"

  "0 3  4     5\n"

  "0 3  5     10\n"

  "0 3  6     7\n"

  "4 2  7     1\n"

  "@attributes\n"

  "source 0\n"

  "target 3\n";

void checkDijkstraCompile()

{

  typedef int VType;

  typedef concepts::Digraph Digraph;

  typedef concepts::ReadMap<Digraph::Arc,VType> LengthMap;

  typedef Dijkstra<Digraph, LengthMap> DType;

  typedef Digraph::Node Node;

  typedef Digraph::Arc Arc;

  Digraph G;

  Node s, t;

  Arc e;

  VType l;

  bool b;

  DType::DistMap d(G);

  DType::PredMap p(G);

  LengthMap length;

  Path<Digraph> pp;

  {

    DType dijkstra_test(G,length);

    dijkstra_test.run(s);

    dijkstra_test.run(s,t);

    l  = dijkstra_test.dist(t);

    e  = dijkstra_test.predArc(t);

    s  = dijkstra_test.predNode(t);

    b  = dijkstra_test.reached(t);

    d  = dijkstra_test.distMap();

    p  = dijkstra_test.predMap();

    pp = dijkstra_test.path(t);

  }

  {

    DType

      ::SetPredMap<concepts::ReadWriteMap<Node,Arc> >

      ::SetDistMap<concepts::ReadWriteMap<Node,VType> >

      ::SetProcessedMap<concepts::WriteMap<Node,bool> >

      ::SetStandardProcessedMap

      ::SetHeap<BinHeap<VType, concepts::ReadWriteMap<Node,int> > >

      ::SetStandardHeap<BinHeap<VType, concepts::ReadWriteMap<Node,int> > >

      ::Create dijkstra_test(G,length);

    dijkstra_test.run(s);

    dijkstra_test.run(s,t);

    l  = dijkstra_test.dist(t);

    e  = dijkstra_test.predArc(t);

    s  = dijkstra_test.predNode(t);

    b  = dijkstra_test.reached(t);

    pp = dijkstra_test.path(t);

  }

}

void checkDijkstraFunctionCompile()

{

  typedef int VType;

  typedef concepts::Digraph Digraph;

  typedef Digraph::Arc Arc;

  typedef Digraph::Node Node;

  typedef concepts::ReadMap<Digraph::Arc,VType> LengthMap;

  Digraph g;

  bool b;

  dijkstra(g,LengthMap()).run(Node());

  b=dijkstra(g,LengthMap()).run(Node(),Node());

  dijkstra(g,LengthMap())

    .predMap(concepts::ReadWriteMap<Node,Arc>())

    .distMap(concepts::ReadWriteMap<Node,VType>())

    .processedMap(concepts::WriteMap<Node,bool>())

    .run(Node());

  b=dijkstra(g,LengthMap())

    .predMap(concepts::ReadWriteMap<Node,Arc>())

    .distMap(concepts::ReadWriteMap<Node,VType>())

    .processedMap(concepts::WriteMap<Node,bool>())

    .path(concepts::Path<Digraph>())

    .dist(VType())

    .run(Node(),Node());

}

template <class Digraph>

void checkDijkstra() {

  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);

  typedef typename Digraph::template ArcMap<int> LengthMap;

  Digraph G;

  Node s, t;

  LengthMap length(G);

  std::istringstream input(test_lgf);

  digraphReader(G, input).

    arcMap("length", length).

    node("source", s).

    node("target", t).

    run();

  Dijkstra<Digraph, LengthMap>

        dijkstra_test(G, length);

  dijkstra_test.run(s);

  check(dijkstra_test.dist(t)==3,"Dijkstra found a wrong path.");