Package org.jacop.constraints.netflow.simplex

Class Arc

java.lang.Object

org.jacop.constraints.netflow.simplex.Arc

public final class Arc
extends java.lang.Object

A directed, residual arc in the graph.

Version:

4.8

Field Summary

Fields

Modifier and Type	Field	Description
int	capacity	The unused (i.e.
ArcCompanion	companion	The arc companion for constraint API.
int	cost	The cost of the Arc cost
boolean	forward	whether this arc is a forward arc or a residual arc
Node	head	The head of the arc (where the arc points to).
int	index	Index in lower arcs array
Arc	sister	The flow of an arc is the residual capacity of its sister arc.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	Arc(Arc sister, Node to)
	Arc(Node tail, Node head)	Special constructor to create artificial arcs.
	Arc(Node tail, Node head, int cost, int lowerCapacity, int upperCapacity)	General constructor to create arcs.

Method Summary

Modifier and Type	Method	Description
void	addFlow(int delta)
void	clear()	Clears an artificial arc
ArcCompanion	getCompanion()
boolean	hasCompanion()
boolean	isInCut(boolean forward)
long	longCost()
java.lang.String	name()
int	reducedCost()	Computes the cost of this arc considering node potentials.
void	set(int newCost, int newCapacity)	Initializes an artificial arc
Node	tail()
java.lang.String	toFlow()
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

head

public final Node head

The head of the arc (where the arc points to). The head of an arc is the tail of its sister arc.

cost

public int cost

The cost of the Arc cost

capacity

public int capacity

The unused (i.e. residual) capacity of the arc

sister

public final Arc sister

The flow of an arc is the residual capacity of its sister arc.

index

public int index

Index in lower arcs array

companion

public ArcCompanion companion

The arc companion for constraint API. Only forward arcs have a companion, residual arcs do not.

forward

public boolean forward

whether this arc is a forward arc or a residual arc

Constructor Detail

Arc

public Arc(Node tail,
           Node head)

Special constructor to create artificial arcs. Should NOT be used in a model. Models should use (or subclass) a NetworkBuilder instead. A NetworkBuilder provides various addArc methods to create arcs more conveniently.

Parameters:

tail - tail of the arc

head - head of the arc

Arc

public Arc(Node tail,
           Node head,
           int cost,
           int lowerCapacity,
           int upperCapacity)

General constructor to create arcs. Models should consider to use (or subclass) a NetworkBuilder instead. A NetworkBuilder provides various addArc methods to create arcs more conveniently.

Parameters:

tail - tail of the arc

head - head of the arc

cost - cost-per-unit of the arc

lowerCapacity - lower capacity of the arc

upperCapacity - upper capacity of the arc

Arc

private Arc(Arc sister,
            Node to)

Method Detail

reducedCost

public int reducedCost()

Computes the cost of this arc considering node potentials.

Returns:

the reduced cost

addFlow

public void addFlow(int delta)

tail

public Node tail()

isInCut

public boolean isInCut(boolean forward)

set

public void set(int newCost,
                int newCapacity)

Initializes an artificial arc

Parameters:

newCost - new cost for the arc

newCapacity - new capacity for the arc

clear

public void clear()

Clears an artificial arc

longCost

public long longCost()

Returns:

cost associated with an arc.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

toFlow

public java.lang.String toFlow()

hasCompanion

public boolean hasCompanion()

getCompanion

public ArcCompanion getCompanion()

name

public java.lang.String name()