Dfs< GR, TR > Class Template Reference
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Detailed Description

template<typename GR, typename TR>
class lemon::Dfs< GR, TR >

This class provides an efficient implementation of the DFS algorithm.

Parameters:

	GR	The graph type the algorithm runs on. The default value is ListGraph. The value of GR is not used directly by Dfs, it is only passed to DfsDefaultTraits.
	TR	Traits class to set various data types used by the algorithm. The default traits class is DfsDefaultTraits<GR>. See DfsDefaultTraits for the documentation of a Dfs traits class.

Author:: Jacint Szabo and Alpar Juttner

#include <lemon/dfs.h>

List of all members.

Query Functions

The result of the DFS algorithm can be obtained using these functions.
Before the use of these functions, either run() or start() must be called.

typedef PredMapPath< Graph,
PredMap > Path

Path path (Node t)

Gives back the shortest path.

int dist (Node v) const

The distance of a node from the root(s).

Edge predEdge (Node v) const

Returns the 'previous edge' of the DFS tree.

Node predNode (Node v) const

Returns the 'previous node' of the DFS tree.

const DistMap & distMap () const

Returns a reference to the NodeMap of distances.

const PredMap & predMap () const

Returns a reference to the DFS edge-tree map.

bool reached (Node v)

Checks if a node is reachable from the root.

Classes

struct DefDistMap

struct DefPredMap

struct DefProcessedMap

class DefProcessedMapToBeDefaultMap

Named parameter for setting the ProcessedMap type to be Graph::NodeMap<bool>. More...

struct DefReachedMap

class UninitializedParameter

Exception for uninitialized parameters. More...

Public Types

typedef TR::Graph Graph

The type of the underlying graph.

typedef Graph::Node Node

typedef Graph::NodeIt NodeIt

typedef Graph::Edge Edge

typedef Graph::OutEdgeIt OutEdgeIt

typedef TR::PredMap PredMap

The type of the map that stores the last edges of the DFS paths.

typedef TR::ReachedMap ReachedMap

The type of the map indicating which nodes are reached.

typedef TR::ProcessedMap ProcessedMap

The type of the map indicating which nodes are processed.

typedef TR::DistMap DistMap

The type of the map that stores the dists of the nodes.

Public Member Functions

Dfs (const Graph &_G)

Constructor.

~Dfs ()

Destructor.

Dfs & predMap (PredMap &m)

Sets the map storing the predecessor edges.

Dfs & distMap (DistMap &m)

Sets the map storing the distances calculated by the algorithm.

Dfs & reachedMap (ReachedMap &m)

Sets the map indicating if a node is reached.

Dfs & processedMap (ProcessedMap &m)

Sets the map indicating if a node is processed.

Execution control

The simplest way to execute the algorithm is to use one of the member functions called run(...).
If you need more control on the execution, first you must call init(), then you can add a source node with addSource(). Finally start() will perform the actual path computation.

void init ()

void addSource (Node s)

Adds a new source node.

Edge processNextEdge ()

Processes the next edge.

OutEdgeIt nextEdge ()

Next edge to be processed.

bool emptyQueue ()

Returns false if there are nodes to be processed in the queue.

int queueSize ()

Returns the number of the nodes to be processed.

void start ()

Executes the algorithm.

void start (Node dest)

Executes the algorithm until dest is reached.

template<class EM >

Edge start (const EM &em)

Executes the algorithm until a condition is met.

void run ()

Runs DFS algorithm to visit all nodes in the graph.

void run (Node s)

Runs DFS algorithm from node s.

int run (Node s, Node t)

Finds the DFS path between s and t.

Private Member Functions

void create_maps ()

Creates the maps if necessary.

Private Attributes

const Graph * G

Pointer to the underlying graph.

PredMap * _pred

Pointer to the map of predecessors edges.

bool local_pred

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

DistMap * _dist

Pointer to the map of distances.

bool local_dist

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

ReachedMap * _reached

Pointer to the map of reached status of the nodes.

bool local_reached

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

ProcessedMap * _processed

Pointer to the map of processed status of the nodes.

bool local_processed

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

Constructor & Destructor Documentation

Dfs ( const Graph & _G ) [inline]

Parameters:

_G

the graph the algorithm will run on.

Member Function Documentation

void create_maps ( ) [inline, private]

Todo:: Better memory allocation (instead of new).

Dfs& predMap ( PredMap & m ) [inline]

Sets the map storing the predecessor edges. If you don't use this function before calling run(), it will allocate one. The destuctor deallocates this automatically allocated map, of course.

Returns:: (*this)

Dfs& distMap ( DistMap & m ) [inline]

Sets the map storing the distances calculated by the algorithm. If you don't use this function before calling run(), it will allocate one. The destuctor deallocates this automatically allocated map, of course.

Returns:: (*this)

Dfs& reachedMap ( ReachedMap & m ) [inline]

Sets the map indicating if a node is reached. If you don't use this function before calling run(), it will allocate one. The destuctor deallocates this automatically allocated map, of course.

Returns:: (*this)

Dfs& processedMap ( ProcessedMap & m ) [inline]

Sets the map indicating if a node is processed. If you don't use this function before calling run(), it will allocate one. The destuctor deallocates this automatically allocated map, of course.

Returns:: (*this)

void init ( ) [inline]

Initializes the internal data structures.

void addSource ( Node s ) [inline]

Adds a new source node to the set of nodes to be processed.

Warning:: dists are wrong (or at least strange) in case of multiple sources.

Edge processNextEdge ( ) [inline]

Processes the next edge.

Returns:: The processed edge.

Precondition:: The stack must not be empty!

OutEdgeIt nextEdge ( ) [inline]

Next edge to be processed.

Returns:: The next edge to be processed or INVALID if the stack is empty.

bool emptyQueue ( ) [inline]

Returns false if there are nodes to be processed in the queue

int queueSize ( ) [inline]

Returns the number of the nodes to be processed in the queue.

void start ( ) [inline]

Executes the algorithm.

Precondition:: init() must be called and at least one node should be added with addSource() before using this function.

This method runs the DFS algorithm from the root node(s) in order to compute the DFS path to each node. The algorithm computes

The DFS tree.
The distance of each node from the root(s) in the DFS tree.

void start ( Node dest ) [inline]

Executes the algorithm until dest is reached.

Precondition:: init() must be called and at least one node should be added with addSource() before using this function.

This method runs the DFS algorithm from the root node(s) in order to compute the DFS path to dest. The algorithm computes

The DFS path to dest.
The distance of dest from the root(s) in the DFS tree.

Edge start ( const EM & em ) [inline]

Executes the algorithm until a condition is met.

Precondition:: init() must be called and at least one node should be added with addSource() before using this function.

Parameters:

em must be a bool (or convertible) edge map. The algorithm will stop when it reaches an edge e with em[e] true.

Returns:: The reached edge e with em[e] true or INVALID if no such edge was found.

Warning:: Contrary to Bfs and Dijkstra, em is an edge map, not a node map.

void run ( ) [inline]

This method runs the DFS algorithm in order to compute the DFS path to each node. The algorithm computes

The DFS tree.
The distance of each node from the root in the DFS tree.

Note:

d.run() is just a shortcut of the following code.

         d.init();
         for (NodeIt it(graph); it != INVALID; ++it) {
           if (!d.reached(it)) {
             d.addSource(it);
             d.start();
           }
         }

void run ( Node s ) [inline]

This method runs the DFS algorithm from a root node s in order to compute the DFS path to each node. The algorithm computes

The DFS tree.
The distance of each node from the root in the DFS tree.

Note:

d.run(s) is just a shortcut of the following code.

         d.init();
         d.addSource(s);
         d.start();

int run	(	Node	s,
		Node	t
	)			`[inline]`

Finds the DFS path between s and t.

Returns:: The length of the DFS s---t path if there exists one, 0 otherwise.

Note:

Apart from the return value, d.run(s,t) is just a shortcut of the following code.

         d.init();
         d.addSource(s);
         d.start(t);

Path path ( Node t ) [inline]

Gives back the shortest path.

Precondition:: The t should be reachable from the source.

int dist ( Node v ) const [inline]

Returns the distance of a node from the root(s).

Precondition:: run() must be called before using this function.

Warning:: If node v is unreachable from the root(s) then the return value of this funcion is undefined.

Edge predEdge ( Node v ) const [inline]

For a node v it returns the 'previous edge' of the DFS path, i.e. it returns the last edge of a DFS path from the root(s) to v. It is INVALID if v is unreachable from the root(s) or v is a root. The DFS tree used here is equal to the DFS tree used in predNode().

Precondition:: Either run() or start() must be called before using this function.

Node predNode ( Node v ) const [inline]

For a node v it returns the 'previous node' of the DFS tree, i.e. it returns the last but one node from a DFS path from the root(s) to v. It is INVALID if v is unreachable from the root(s) or if v itself a root. The DFS tree used here is equal to the DFS tree used in predEdge().

Precondition:: Either run() or start() must be called before using this function.

const DistMap& distMap ( ) const [inline]

Returns a reference to the NodeMap of distances.

Precondition:: Either run() or init() must be called before using this function.

const PredMap& predMap ( ) const [inline]

Returns a reference to the NodeMap of the edges of the DFS tree.

Precondition:: Either run() or init() must be called before using this function.

bool reached ( Node v ) [inline]

Returns true if v is reachable from the root(s).

Warning:: The source nodes are inditated as unreachable.

Precondition:: Either run() or start() must be called before using this function.


Query Functions
The result of the DFS algorithm can be obtained using these functions. Before the use of these functions, either run() or start() must be called.
typedef PredMapPath< Graph, PredMap >	Path
Path	path (Node t)
	Gives back the shortest path.
int	dist (Node v) const
	The distance of a node from the root(s).
Edge	predEdge (Node v) const
	Returns the 'previous edge' of the DFS tree.
Node	predNode (Node v) const
	Returns the 'previous node' of the DFS tree.
const DistMap &	distMap () const
	Returns a reference to the NodeMap of distances.
const PredMap &	predMap () const
	Returns a reference to the DFS edge-tree map.
bool	reached (Node v)
	Checks if a node is reachable from the root.
Classes
struct	DefDistMap
struct	DefPredMap
struct	DefProcessedMap
class	DefProcessedMapToBeDefaultMap
	Named parameter for setting the ProcessedMap type to be Graph::NodeMap<bool>. More...
struct	DefReachedMap
class	UninitializedParameter
	Exception for uninitialized parameters. More...
Public Types
typedef TR::Graph	Graph
	The type of the underlying graph.
typedef Graph::Node	Node

typedef Graph::NodeIt	NodeIt

typedef Graph::Edge	Edge

typedef Graph::OutEdgeIt	OutEdgeIt

typedef TR::PredMap	PredMap
	The type of the map that stores the last edges of the DFS paths.
typedef TR::ReachedMap	ReachedMap
	The type of the map indicating which nodes are reached.
typedef TR::ProcessedMap	ProcessedMap
	The type of the map indicating which nodes are processed.
typedef TR::DistMap	DistMap
	The type of the map that stores the dists of the nodes.
Public Member Functions
	Dfs (const Graph &_G)
	Constructor.
	~Dfs ()
	Destructor.
Dfs &	predMap (PredMap &m)
	Sets the map storing the predecessor edges.
Dfs &	distMap (DistMap &m)
	Sets the map storing the distances calculated by the algorithm.
Dfs &	reachedMap (ReachedMap &m)
	Sets the map indicating if a node is reached.
Dfs &	processedMap (ProcessedMap &m)
	Sets the map indicating if a node is processed.
Execution control
The simplest way to execute the algorithm is to use one of the member functions called `run`(...). If you need more control on the execution, first you must call init(), then you can add a source node with addSource(). Finally start() will perform the actual path computation.
void	init ()
void	addSource (Node s)
	Adds a new source node.
Edge	processNextEdge ()
	Processes the next edge.
OutEdgeIt	nextEdge ()
	Next edge to be processed.
bool	emptyQueue ()
	Returns `false` if there are nodes to be processed in the queue.
int	queueSize ()
	Returns the number of the nodes to be processed.
void	start ()
	Executes the algorithm.
void	start (Node dest)
	Executes the algorithm until `dest` is reached.
template<class EM >
Edge	start (const EM &em)
	Executes the algorithm until a condition is met.
void	run ()
	Runs DFS algorithm to visit all nodes in the graph.
void	run (Node s)
	Runs DFS algorithm from node `s`.
int	run (Node s, Node t)
	Finds the DFS path between `s` and `t`.
Private Member Functions
void	create_maps ()
	Creates the maps if necessary.
Private Attributes
const Graph *	G
	Pointer to the underlying graph.
PredMap *	_pred
	Pointer to the map of predecessors edges.
bool	local_pred
	Indicates if _pred is locally allocated (`true`) or not.
DistMap *	_dist
	Pointer to the map of distances.
bool	local_dist
	Indicates if _dist is locally allocated (`true`) or not.
ReachedMap *	_reached
	Pointer to the map of reached status of the nodes.
bool	local_reached
	Indicates if _reached is locally allocated (`true`) or not.
ProcessedMap *	_processed
	Pointer to the map of processed status of the nodes.
bool	local_processed
	Indicates if _processed is locally allocated (`true`) or not.

Dfs< GR, TR > Class Template Reference [Graph Search]

Detailed Description

template<typename GR, typename TR> class lemon::Dfs< GR, TR >

Query Functions

Classes

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Constructor & Destructor Documentation

Member Function Documentation

Dfs< GR, TR > Class Template Reference
[Graph Search]

template<typename GR, typename TR>
class lemon::Dfs< GR, TR >