RhodeCode

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

 *

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

 *

 * 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.

 *

 */

///\ingroup demos

///\file

///\brief Argument parser demo

///

/// This example shows how the argument parser can be used.

///

/// \include arg_parser_demo.cc

#include <lemon/arg_parser.h>

using namespace lemon;

int main(int argc, char **argv)

{

  // Initialize the argument parser

  ArgParser ap(argc, argv);

  int i;

  std::string s;

  double d = 1.0;

  bool b, nh;

  bool g1, g2, g3;

  // Add a mandatory integer option with storage reference

  ap.refOption("n", "An integer input.", i, true);

  // Add a double option with storage reference (the default value is 1.0)

  ap.refOption("val", "A double input.", d);

  // Add a double option without storage reference (the default value is 3.14)

  ap.doubleOption("val2", "A double input.", 3.14);

  // Set synonym for -val option

  ap.synonym("vals", "val");

  // Add a string option

  ap.refOption("name", "A string input.", s);

  // Add bool options

  ap.refOption("f", "A switch.", b)

    .refOption("nohelp", "", nh)

    .refOption("gra", "Choice A", g1)

    .refOption("grb", "Choice B", g2)

    .refOption("grc", "Choice C", g3);

  // Bundle -gr* options into a group

  ap.optionGroup("gr", "gra")

    .optionGroup("gr", "grb")

    .optionGroup("gr", "grc");

  // Set the group mandatory

  ap.mandatoryGroup("gr");

  // Set the options of the group exclusive (only one option can be given)

  ap.onlyOneGroup("gr");

  // Add non-parsed arguments (e.g. input files)

  ap.other("infile", "The input file.")

    .other("...");

  // Throw an exception when problems occurs. The default behavior is to

  // exit(1) on these cases, but this makes Valgrind falsely warn

  // about memory leaks.

  ap.throwOnProblems();

  // Perform the parsing process

  // (in case of any error it terminates the program)

  // The try {} construct is necessary only if the ap.trowOnProblems()

  // setting is in use.

  try {

    ap.parse();

  } catch (ArgParserException &) { return 1; }

  // Check each option if it has been given and print its value

  std::cout << "Parameters of '" << ap.commandName() << "':\n";

  std::cout << "  Value of -n: " << i << std::endl;

  if(ap.given("val")) std::cout << "  Value of -val: " << d << std::endl;

  if(ap.given("val2")) {

    d = ap["val2"];

    std::cout << "  Value of -val2: " << d << std::endl;

  }

  if(ap.given("name")) std::cout << "  Value of -name: " << s << std::endl;

  if(ap.given("f")) std::cout << "  -f is given\n";

  if(ap.given("nohelp")) std::cout << "  Value of -nohelp: " << nh << std::endl;

  if(ap.given("gra")) std::cout << "  -gra is given\n";

  if(ap.given("grb")) std::cout << "  -grb is given\n";

  if(ap.given("grc")) std::cout << "  -grc is given\n";

  switch(ap.files().size()) {

  case 0:

    std::cout << "  No file argument was given.\n";

    break;

  case 1:

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

 *

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

 *

 * 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.

 *

 */

namespace lemon {

/**

@defgroup datas Data Structures

This group contains the several data structures implemented in LEMON.

*/

/**

@defgroup graphs Graph Structures

@ingroup datas

\brief Graph structures implemented in LEMON.

The implementation of combinatorial algorithms heavily relies on

efficient graph implementations. LEMON offers data structures which are

planned to be easily used in an experimental phase of implementation studies,

and thereafter the program code can be made efficient by small modifications.

The most efficient implementation of diverse applications require the

usage of different physical graph implementations. These differences

appear in the size of graph we require to handle, memory or time usage

limitations or in the set of operations through which the graph can be

accessed.  LEMON provides several physical graph structures to meet

the diverging requirements of the possible users.  In order to save on

running time or on memory usage, some structures may fail to provide

some graph features like arc/edge or node deletion.

Alteration of standard containers need a very limited number of

operations, these together satisfy the everyday requirements.

In the case of graph structures, different operations are needed which do

not alter the physical graph, but gives another view. If some nodes or

arcs have to be hidden or the reverse oriented graph have to be used, then

this is the case. It also may happen that in a flow implementation

the residual graph can be accessed by another algorithm, or a node-set

is to be shrunk for another algorithm.

LEMON also provides a variety of graphs for these requirements called

\ref graph_adaptors "graph adaptors". Adaptors cannot be used alone but only

in conjunction with other graph representations.

You are free to use the graph structure that fit your requirements

the best, most graph algorithms and auxiliary data structures can be used

with any graph structure.

<b>See also:</b> \ref graph_concepts "Graph Structure Concepts".

*/

/**

@defgroup graph_adaptors Adaptor Classes for Graphs

@ingroup graphs

\brief Adaptor classes for digraphs and graphs

This group contains several useful adaptor classes for digraphs and graphs.

The main parts of LEMON are the different graph structures, generic

graph algorithms, graph concepts, which couple them, and graph

adaptors. While the previous notions are more or less clear, the

latter one needs further explanation. Graph adaptors are graph classes

which serve for considering graph structures in different ways.

A short example makes this much clearer.  Suppose that we have an

instance \c g of a directed graph type, say ListDigraph and an algorithm

\code

template <typename Digraph>

int algorithm(const Digraph&);

\endcode

is needed to run on the reverse oriented graph.  It may be expensive

(in time or in memory usage) to copy \c g with the reversed

arcs.  In this case, an adaptor class is used, which (according

to LEMON \ref concepts::Digraph "digraph concepts") works as a digraph.

The adaptor uses the original digraph structure and digraph operations when

methods of the reversed oriented graph are called.  This means that the adaptor

have minor memory usage, and do not perform sophisticated algorithmic

actions.  The purpose of it is to give a tool for the cases when a

graph have to be used in a specific alteration.  If this alteration is

obtained by a usual construction like filtering the node or the arc set or

considering a new orientation, then an adaptor is worthwhile to use.

To come back to the reverse oriented graph, in this situation

\code

template<typename Digraph> class ReverseDigraph;

\endcode

template class can be used. The code looks as follows

\code

ListDigraph g;

ReverseDigraph<ListDigraph> rg(g);

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

 *

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

 *

 * 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.

 *

 */

/**

\mainpage LEMON Documentation

\section intro Introduction

<b>LEMON</b> stands for <i><b>L</b>ibrary for <b>E</b>fficient <b>M</b>odeling

and <b>O</b>ptimization in <b>N</b>etworks</i>.

It is a C++ template library providing efficient implementations of common

data structures and algorithms with focus on combinatorial optimization

tasks connected mainly with graphs and networks. 

<b>

LEMON is an <a class="el" href="http://opensource.org/">open&nbsp;source</a>

project.

You are free to use it in your commercial or

non-commercial applications under very permissive

\ref license "license terms".

</b>

The project is maintained by the 

<a href="http://www.cs.elte.hu/egres/">Egerv&aacute;ry Research Group on

Combinatorial Optimization</a> \ref egres

at the Operations Research Department of the

<a href="http://www.elte.hu/en/">E&ouml;tv&ouml;s Lor&aacute;nd University</a>,

Budapest, Hungary.

LEMON is also a member of the <a href="http://www.coin-or.org/">COIN-OR</a>

initiative \ref coinor.

\section howtoread How to Read the Documentation

If you would like to get to know the library, see

<a class="el" href="http://lemon.cs.elte.hu/pub/tutorial/">LEMON Tutorial</a>.

If you are interested in starting to use the library, see the <a class="el"

href="http://lemon.cs.elte.hu/trac/lemon/wiki/InstallGuide/">Installation

Guide</a>.

If you know what you are looking for, then try to find it under the

<a class="el" href="modules.html">Modules</a> section.

If you are a user of the old (0.x) series of LEMON, please check out the

\ref migration "Migration Guide" for the backward incompatibilities.

*/

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

 *

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

 *

 * 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.

 *

 */

namespace lemon {

/**

\page min_cost_flow Minimum Cost Flow Problem

\section mcf_def Definition (GEQ form)

The \e minimum \e cost \e flow \e problem is to find a feasible flow of

minimum total cost from a set of supply nodes to a set of demand nodes

in a network with capacity constraints (lower and upper bounds)

and arc costs \ref amo93networkflows.

Formally, let \f$G=(V,A)\f$ be a digraph, \f$lower: A\rightarrow\mathbf{R}\f$,

\f$upper: A\rightarrow\mathbf{R}\cup\{+\infty\}\f$ denote the lower and

upper bounds for the flow values on the arcs, for which

\f$lower(uv) \leq upper(uv)\f$ must hold for all \f$uv\in A\f$,

\f$cost: A\rightarrow\mathbf{R}\f$ denotes the cost per unit flow

on the arcs and \f$sup: V\rightarrow\mathbf{R}\f$ denotes the

signed supply values of the nodes.

If \f$sup(u)>0\f$, then \f$u\f$ is a supply node with \f$sup(u)\f$

supply, if \f$sup(u)<0\f$, then \f$u\f$ is a demand node with

\f$-sup(u)\f$ demand.

A minimum cost flow is an \f$f: A\rightarrow\mathbf{R}\f$ solution

of the following optimization problem.

\f[ \min\sum_{uv\in A} f(uv) \cdot cost(uv) \f]

\f[ \sum_{uv\in A} f(uv) - \sum_{vu\in A} f(vu) \geq

    sup(u) \quad \forall u\in V \f]

\f[ lower(uv) \leq f(uv) \leq upper(uv) \quad \forall uv\in A \f]

The sum of the supply values, i.e. \f$\sum_{u\in V} sup(u)\f$ must be

zero or negative in order to have a feasible solution (since the sum

of the expressions on the left-hand side of the inequalities is zero).

It means that the total demand must be greater or equal to the total

supply and all the supplies have to be carried out from the supply nodes,

but there could be demands that are not satisfied.

If \f$\sum_{u\in V} sup(u)\f$ is zero, then all the supply/demand

constraints have to be satisfied with equality, i.e. all demands

have to be satisfied and all supplies have to be used.

\section mcf_algs Algorithms

LEMON contains several algorithms for solving this problem, for more

information see \ref min_cost_flow_algs "Minimum Cost Flow Algorithms".

A feasible solution for this problem can be found using \ref Circulation.

\section mcf_dual Dual Solution

The dual solution of the minimum cost flow problem is represented by

node potentials \f$\pi: V\rightarrow\mathbf{R}\f$.

An \f$f: A\rightarrow\mathbf{R}\f$ primal feasible solution is optimal

if and only if for some \f$\pi: V\rightarrow\mathbf{R}\f$ node potentials

the following \e complementary \e slackness optimality conditions hold.

 - For all \f$uv\in A\f$ arcs:

   - if \f$cost^\pi(uv)>0\f$, then \f$f(uv)=lower(uv)\f$;

   - if \f$lower(uv)<f(uv)<upper(uv)\f$, then \f$cost^\pi(uv)=0\f$;

   - if \f$cost^\pi(uv)<0\f$, then \f$f(uv)=upper(uv)\f$.

 - For all \f$u\in V\f$ nodes:

   - \f$\pi(u)\leq 0\f$;

   - if \f$\sum_{uv\in A} f(uv) - \sum_{vu\in A} f(vu) \neq sup(u)\f$,

     then \f$\pi(u)=0\f$.

Here \f$cost^\pi(uv)\f$ denotes the \e reduced \e cost of the arc

\f$uv\in A\f$ with respect to the potential function \f$\pi\f$, i.e.

\f[ cost^\pi(uv) = cost(uv) + \pi(u) - \pi(v).\f]

All algorithms provide dual solution (node potentials), as well,

if an optimal flow is found.

\section mcf_eq Equality Form

The above \ref mcf_def "definition" is actually more general than the

usual formulation of the minimum cost flow problem, in which strict

equalities are required in the supply/demand contraints.

\f[ \min\sum_{uv\in A} f(uv) \cdot cost(uv) \f]

\f[ \sum_{uv\in A} f(uv) - \sum_{vu\in A} f(vu) =

    sup(u) \quad \forall u\in V \f]

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

 *

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

 *

 * 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_ADAPTORS_H

#define LEMON_ADAPTORS_H

/// \ingroup graph_adaptors

/// \file

/// \brief Adaptor classes for digraphs and graphs

///

/// This file contains several useful adaptors for digraphs and graphs.

#include <lemon/core.h>

#include <lemon/maps.h>

#include <lemon/bits/variant.h>

#include <lemon/bits/graph_adaptor_extender.h>

#include <lemon/bits/map_extender.h>

#include <lemon/tolerance.h>

#include <algorithm>

namespace lemon {

#ifdef _MSC_VER

#define LEMON_SCOPE_FIX(OUTER, NESTED) OUTER::NESTED

#else

#define LEMON_SCOPE_FIX(OUTER, NESTED) typename OUTER::template NESTED

#endif

  template<typename DGR>

  class DigraphAdaptorBase {

  public:

    typedef DGR Digraph;

    typedef DigraphAdaptorBase Adaptor;

  protected:

    DGR* _digraph;

    DigraphAdaptorBase() : _digraph(0) { }

    void initialize(DGR& digraph) { _digraph = &digraph; }

  public:

    DigraphAdaptorBase(DGR& digraph) : _digraph(&digraph) { }

    typedef typename DGR::Node Node;

    typedef typename DGR::Arc Arc;

    void first(Node& i) const { _digraph->first(i); }

    void first(Arc& i) const { _digraph->first(i); }

    void firstIn(Arc& i, const Node& n) const { _digraph->firstIn(i, n); }

    void firstOut(Arc& i, const Node& n ) const { _digraph->firstOut(i, n); }

    void next(Node& i) const { _digraph->next(i); }

    void next(Arc& i) const { _digraph->next(i); }

    void nextIn(Arc& i) const { _digraph->nextIn(i); }

    void nextOut(Arc& i) const { _digraph->nextOut(i); }

    Node source(const Arc& a) const { return _digraph->source(a); }

    Node target(const Arc& a) const { return _digraph->target(a); }

    typedef NodeNumTagIndicator<DGR> NodeNumTag;

    int nodeNum() const { return _digraph->nodeNum(); }

    typedef ArcNumTagIndicator<DGR> ArcNumTag;

    int arcNum() const { return _digraph->arcNum(); }

    typedef FindArcTagIndicator<DGR> FindArcTag;

    Arc findArc(const Node& u, const Node& v, const Arc& prev = INVALID) const {

      return _digraph->findArc(u, v, prev);

    }

    Node addNode() { return _digraph->addNode(); }

    Arc addArc(const Node& u, const Node& v) { return _digraph->addArc(u, v); }

    void erase(const Node& n) { _digraph->erase(n); }

    void erase(const Arc& a) { _digraph->erase(a); }

    void clear() { _digraph->clear(); }

    int id(const Node& n) const { return _digraph->id(n); }

    int id(const Arc& a) const { return _digraph->id(a); }

    Node nodeFromId(int ix) const { return _digraph->nodeFromId(ix); }

    Arc arcFromId(int ix) const { return _digraph->arcFromId(ix); }

    int maxNodeId() const { return _digraph->maxNodeId(); }

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

 *

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

 *

 * 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.

 *

 */

#include <lemon/arg_parser.h>

namespace lemon {

  void ArgParser::_terminate(ArgParserException::Reason reason) const

  {

    if(_exit_on_problems)

      exit(1);

    else throw(ArgParserException(reason));

  }

  void ArgParser::_showHelp(void *p)

  {

    (static_cast<ArgParser*>(p))->showHelp();

    (static_cast<ArgParser*>(p))->_terminate(ArgParserException::HELP);

  }

  ArgParser::ArgParser(int argc, const char * const *argv)

    :_argc(argc), _argv(argv), _command_name(argv[0]),

    _exit_on_problems(true) {

    funcOption("-help","Print a short help message",_showHelp,this);

    synonym("help","-help");

    synonym("h","-help");

  }

  ArgParser::~ArgParser()

  {

    for(Opts::iterator i=_opts.begin();i!=_opts.end();++i)

      if(i->second.self_delete)

        switch(i->second.type) {

        case BOOL:

          delete i->second.bool_p;

          break;

        case STRING:

          delete i->second.string_p;

          break;

        case DOUBLE:

          delete i->second.double_p;

          break;

        case INTEGER:

          delete i->second.int_p;

          break;

        case UNKNOWN:

          break;

        case FUNC:

          break;

        }

  }

  ArgParser &ArgParser::intOption(const std::string &name,

                               const std::string &help,

                               int value, bool obl)

  {

    ParData p;

    p.int_p=new int(value);

    p.self_delete=true;

    p.help=help;

    p.type=INTEGER;

    p.mandatory=obl;

    _opts[name]=p;

    return *this;

  }

  ArgParser &ArgParser::doubleOption(const std::string &name,

                               const std::string &help,

                               double value, bool obl)

  {

    ParData p;

    p.double_p=new double(value);

    p.self_delete=true;

    p.help=help;

    p.type=DOUBLE;

    p.mandatory=obl;

    _opts[name]=p;

    return *this;

  }

  ArgParser &ArgParser::boolOption(const std::string &name,

                               const std::string &help,

                               bool value, bool obl)

  {

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

 *

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

 *

 * 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_ARG_PARSER_H

#define LEMON_ARG_PARSER_H

#include <vector>

#include <map>

#include <list>

#include <string>

#include <iostream>

#include <sstream>

#include <algorithm>

#include <lemon/assert.h>

///\ingroup misc

///\file

///\brief A tool to parse command line arguments.

namespace lemon {

  ///Exception used by ArgParser

  class ArgParserException : public Exception {

  public:

    enum Reason {

      HELP,         /// <tt>--help</tt> option was given

      UNKNOWN_OPT,  /// Unknown option was given

      INVALID_OPT   /// Invalid combination of options

    };

  private:

    Reason _reason;

  public:

    ///Constructor

    ArgParserException(Reason r) throw() : _reason(r) {}

    ///Virtual destructor

    virtual ~ArgParserException() throw() {}

    ///A short description of the exception

    virtual const char* what() const throw() {

      switch(_reason)

        {

        case HELP:

          return "lemon::ArgParseException: ask for help";

          break;

        case UNKNOWN_OPT:

          return "lemon::ArgParseException: unknown option";

          break;

        case INVALID_OPT:

          return "lemon::ArgParseException: invalid combination of options";

          break;

        }

      return "";

    }

    ///Return the reason for the failure

    Reason reason() const {return _reason; }

  };

  ///Command line arguments parser

  ///\ingroup misc

  ///Command line arguments parser.

  ///

  ///For a complete example see the \ref arg_parser_demo.cc demo file.

  class ArgParser {

    static void _showHelp(void *p);

  protected:

    int _argc;

    const char * const *_argv;

    enum OptType { UNKNOWN=0, BOOL=1, STRING=2, DOUBLE=3, INTEGER=4, FUNC=5 };

    class ParData {

    public:

      union {

        bool *bool_p;

        int *int_p;

        double *double_p;

        std::string *string_p;

        struct {

          void (*p)(void *);

          void *data;

        } func_p;

 *

 *

 * 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_BELLMAN_FORD_H

#define LEMON_BELLMAN_FORD_H

/// \ingroup shortest_path

/// \file

/// \brief Bellman-Ford algorithm.

#include <lemon/list_graph.h>

#include <lemon/bits/path_dump.h>

#include <lemon/core.h>

#include <lemon/error.h>

#include <lemon/maps.h>

#include <lemon/tolerance.h>

#include <lemon/path.h>

#include <limits>

namespace lemon {

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

  ///  

  /// This operation traits class defines all computational operations

  /// and constants that are used in the Bellman-Ford algorithm.

  /// The default implementation is based on the \c numeric_limits class.

  /// If the numeric type does not have infinity value, then the maximum

  /// value is used as extremal infinity value.

  ///

  /// \see BellmanFordToleranceOperationTraits

  template <

    typename V, 

    bool has_inf = std::numeric_limits<V>::has_infinity>

  struct BellmanFordDefaultOperationTraits {

    /// \brief Value type for the algorithm.

    typedef V Value;

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

    static Value zero() {

      return static_cast<Value>(0);

    }

    /// \brief Gives back the positive infinity value of the type.

    static Value infinity() {

      return std::numeric_limits<Value>::infinity();

    }

    /// \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 \c true only if the first value is less than

    /// the second.

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

      return left < right;

    }

  };

  template <typename V>

  struct BellmanFordDefaultOperationTraits<V, false> {

    typedef V Value;

    static Value zero() {

      return static_cast<Value>(0);

    }

    static Value infinity() {

      return std::numeric_limits<Value>::max();

    }

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

      if (left == infinity() || right == infinity()) return infinity();

      return left + right;

    }

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

      return left < right;

    }

  };

  /// \brief Operation traits for the BellmanFord algorithm class

  /// using tolerance.

  ///

  /// This operation traits class defines all computational operations

  /// and constants that are used in the Bellman-Ford algorithm.

  /// The only difference between this implementation and

  /// \ref BellmanFordDefaultOperationTraits is that this class uses

  /// the \ref Tolerance "tolerance technique" in its \ref less()

  /// function.

  ///

  /// \tparam V The value type.

  /// \tparam eps The epsilon value for the \ref less() function.

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

 *

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

 *

 * 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_BFS_H

#define LEMON_BFS_H

///\ingroup search

///\file

///\brief BFS algorithm.

#include <lemon/list_graph.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 {

  ///Default traits class of Bfs class.

  ///Default traits class of Bfs class.

  ///\tparam GR Digraph type.

  template<class GR>

  struct BfsDefaultTraits

  {

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

    typedef GR Digraph;

    ///\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 conform to the \ref concepts::WriteMap "WriteMap" concept.

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

    ///Instantiates a \c PredMap.

    ///This function instantiates a \ref PredMap.

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

    ///\ref PredMap.

    static PredMap *createPredMap(const Digraph &g)

    {

      return new PredMap(g);

    }

    ///The type of the map that indicates which nodes are processed.

    ///The type of the map that indicates which nodes are processed.

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

    ///By default, it is a NullMap.

    typedef NullMap<typename Digraph::Node,bool> ProcessedMap;

    ///Instantiates a \c ProcessedMap.

    ///This function instantiates a \ref ProcessedMap.

    ///\param g is the digraph, to which

    ///we would like to define the \ref ProcessedMap

#ifdef DOXYGEN

    static ProcessedMap *createProcessedMap(const Digraph &g)

#else

    static ProcessedMap *createProcessedMap(const Digraph &)

#endif

    {

      return new ProcessedMap();

    }

    ///The type of the map that indicates which nodes are reached.

    ///The type of the map that indicates which nodes are reached.

    typedef typename Digraph::template NodeMap<bool> ReachedMap;

    ///Instantiates a \c ReachedMap.

    ///This function instantiates a \ref ReachedMap.

    ///\param g is the digraph, to which

    ///we would like to define the \ref ReachedMap.

    static ReachedMap *createReachedMap(const Digraph &g)

    {

      return new ReachedMap(g);

    }

    ///The type of the map that stores the distances of the nodes.

    ///The type of the map that stores the distances of the nodes.

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

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

    ///Instantiates a \c DistMap.

    ///This function instantiates a \ref DistMap.

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

    ///\ref DistMap.

    static DistMap *createDistMap(const Digraph &g)

    {

      return new DistMap(g);

    }

  };

  ///%BFS algorithm class.

  ///\ingroup search

  ///This class provides an efficient implementation of the %BFS algorithm.

  ///

  ///There is also a \ref bfs() "function-type interface" for the BFS

  ///algorithm, which is convenient in the simplier cases and it can be

  ///used easier.

  ///

  ///\tparam GR The type of the digraph the algorithm runs on.

  ///The default type is \ref ListDigraph.

  ///\tparam TR The traits class that defines various types used by the

  ///algorithm. By default, it is \ref BfsDefaultTraits

  ///"BfsDefaultTraits<GR>".

  ///In most cases, this parameter should not be set directly,

  ///consider to use the named template parameters instead.

#ifdef DOXYGEN

  template <typename GR,

            typename TR>

#else

  template <typename GR=ListDigraph,

            typename TR=BfsDefaultTraits<GR> >

#endif

  class Bfs {

  public:

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

    typedef typename TR::Digraph Digraph;

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

    ///shortest paths.

    typedef typename TR::PredMap PredMap;

    ///The type of the map that stores the distances of the nodes.

    typedef typename TR::DistMap DistMap;

    ///The type of the map that indicates which nodes are reached.

    typedef typename TR::ReachedMap ReachedMap;

    ///The type of the map that indicates which nodes are processed.

    typedef typename TR::ProcessedMap ProcessedMap;

    ///The type of the paths.

    typedef PredMapPath<Digraph, PredMap> Path;

    ///The \ref BfsDefaultTraits "traits class" of the algorithm.

    typedef TR Traits;

  private:

    typedef typename Digraph::Node Node;

    typedef typename Digraph::NodeIt NodeIt;

    typedef typename Digraph::Arc Arc;

    typedef typename Digraph::OutArcIt OutArcIt;

    //Pointer to the underlying digraph.

    const Digraph *G;

    //Pointer to the map of predecessor arcs.

    PredMap *_pred;

    //Indicates if _pred is locally allocated (true) or not.

    bool local_pred;

    //Pointer to the map of distances.

    DistMap *_dist;

    //Indicates if _dist is locally allocated (true) or not.

    bool local_dist;

    //Pointer to the map of reached status of the nodes.

    ReachedMap *_reached;

    //Indicates if _reached is locally allocated (true) or not.

    bool local_reached;

    //Pointer to the map of processed status of the nodes.

    ProcessedMap *_processed;

    //Indicates if _processed is locally allocated (true) or not.

    bool local_processed;

    std::vector<typename Digraph::Node> _queue;

    int _queue_head,_queue_tail,_queue_next_dist;

    int _curr_dist;

    //Creates the maps if necessary.

    void create_maps()

    {

      if(!_pred) {

        local_pred = true;

        _pred = Traits::createPredMap(*G);

      }

      if(!_dist) {

        local_dist = true;

        _dist = Traits::createDistMap(*G);

      }

      if(!_reached) {

        local_reached = true;

        _reached = Traits::createReachedMap(*G);

      }

      if(!_processed) {

        local_processed = true;

        _processed = Traits::createProcessedMap(*G);

      }

    }

  protected:

    Bfs() {}

  public:

    typedef Bfs Create;

    ///\name Named Template Parameters

    ///@{

    template <class T>

    struct SetPredMapTraits : public Traits {

      typedef T PredMap;

      static PredMap *createPredMap(const Digraph &)

      {

        LEMON_ASSERT(false, "PredMap is not initialized");

        return 0; // ignore warnings

      }

    };

    ///\brief \ref named-templ-param "Named parameter" for setting

    ///\c PredMap type.

    ///

    ///\ref named-templ-param "Named parameter" for setting

    ///\c PredMap type.

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

    template <class T>

    struct SetPredMap : public Bfs< Digraph, SetPredMapTraits<T> > {

      typedef Bfs< Digraph, SetPredMapTraits<T> > Create;

    };

    template <class T>

    struct SetDistMapTraits : public Traits {

      typedef T DistMap;

      static DistMap *createDistMap(const Digraph &)