LinkedElevator< GR, Item > Class Template Reference

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Detailed Description

template<class GR, class Item>
class lemon::LinkedElevator< GR, Item >

A class for handling "labels" in push-relabel type algorithms.

Using this class you can assign "labels" (nonnegative integer numbers) to the edges or nodes of a graph, manipulate and query them through operations typically arising in "push-relabel" type algorithms.

Each item is either active or not, and you can also choose a highest level active item.

See also:

Elevator

Parameters:

GR	Type of the underlying graph.
Item	Type of the items the data is assigned to (GR::Node, GR::Arc or GR::Edge).

#include <lemon/elevator.h>

List of all members.

Public Member Functions
	LinkedElevator (const GR &graph, int max_level)
	Constructor with given maximum level.
	LinkedElevator (const GR &graph)
	Constructor.
void	activate (Item i)
	Activate item i.
void	deactivate (Item i)
	Deactivate item i.
bool	active (Item i) const
	Query whether item i is active.
int	operator[] (Item i) const
	Return the level of item i.
int	onLevel (int l) const
	Return the number of items on level l.
bool	emptyLevel (int l) const
	Return true if the level is empty.
int	aboveLevel (int l) const
	Return the number of items above level l.
int	activesOnLevel (int l) const
	Return the number of active items on level l.
bool	activeFree (int l) const
	Return true if there is no active item on level l.
int	maxLevel () const
	Return the maximum allowed level.
void	lift (Item i, int new_level)
	Lift an active item to a higher level.
void	dirtyTopButOne (Item i)
	Move an inactive item to the top but one level (in a dirty way).
void	liftToTop (int l)
	Lift all items on and above the given level to the top level.
Highest Active Item
Functions for working with the highest level active item.
Item	highestActive () const
	Return a highest level active item.
int	highestActiveLevel () const
	Return the highest active level.
void	liftHighestActive ()
	Lift the highest active item by one.
void	liftHighestActive (int new_level)
	Lift the highest active item to the given level.
void	liftHighestActiveToTop ()
	Lift the highest active item to the top level.
Active Item on Certain Level
Functions for working with the active items.
Item	activeOn (int l) const
	Return an active item on level l.
Item	liftActiveOn (int l)
	Lift the active item returned by activeOn(l) by one.
void	liftActiveOn (int l, int new_level)
	Lift the active item returned by activeOn(l) to the given level.
void	liftActiveToTop (int l)
	Lift the active item returned by activeOn(l) to the top level.
Initialization
Using these functions you can initialize the levels of the items. The initialization must be started with calling initStart(). Then the items should be listed level by level starting with the lowest one (level 0) using initAddItem() and initNewLevel(). Finally initFinish() must be called. The items not listed are put on the highest level.
void	initStart ()
	Start the initialization process.
void	initAddItem (Item i)
	Add an item to the current level.
void	initNewLevel ()
	Start a new level.
void	initFinish ()
	Finalize the initialization process.

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Constructor & Destructor Documentation

LinkedElevator	(	const GR &	graph,
		int	max_level
	)		[inline]

Constructor with given maximum level.

Parameters:

graph	The underlying graph.
max_level	The maximum allowed level. Set the range of the possible labels to [0..max_level].

LinkedElevator

(

const GR &

graph

)

[inline]

Constructor.

Parameters:

graph

The underlying graph. Set the range of the possible labels to [0..max_level], where max_level is equal to the number of labeled items in the graph.

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Member Function Documentation

void activate

(

Item

i

)

[inline]

Activate item i.

Precondition:

Item i shouldn't be active before.

void deactivate

(

Item

i

)

[inline]

Deactivate item i.

Precondition:

Item i must be active before.

Item highestActive

(

)

const [inline]

Return a highest level active item or INVALID if there is no active item.

int highestActiveLevel

(

)

const [inline]

Return the level of the highest active item or -1 if there is no active item.

void liftHighestActive

(

)

[inline]

Lift the item returned by highestActive() by one.

void liftHighestActive

(

int

new_level

)

[inline]

Lift the item returned by highestActive() to level new_level.

Warning:

new_level must be strictly higher than the current level.

void liftHighestActiveToTop

(

)

[inline]

Lift the item returned by highestActive() to the top level and deactivate it.

Item activeOn

(

int

l

)

const [inline]

Return an active item on level l or INVALID if there is no such an item. (l must be from the range [0...max_level].

Item liftActiveOn

(

int

l

)

[inline]

Lift the active item returned by activeOn(l) by one.

void liftActiveOn	(	int	l,
		int	new_level
	)		[inline]

Lift the active item returned by activeOn(l) to the given level.

void liftActiveToTop

(

int

l

)

[inline]

Lift the active item returned by activeOn(l) to the top level and deactivate it.

void lift	(	Item	i,
		int	new_level
	)		[inline]

Lift an active item to a higher level.

Parameters:

i	The item to be lifted. It must be active.
new_level	The new level of i. It must be strictly higher than the current level.

void dirtyTopButOne

(

Item

i

)

[inline]

This function moves an inactive item from the top level to the top but one level (in a dirty way).

Warning:

It makes the underlying datastructure corrupt, so use it only if you really know what it is for.

Precondition:

The item is on the top level.

void liftToTop

(

int

l

)

[inline]

This function lifts all items on and above level l to the top level and deactivates them.

void initNewLevel

(

)

[inline]

Start a new level. It shouldn't be used before the items on level 0 are listed.