boone

Class Link

java.lang.Object

boone.BrainPart

boone.Link

All Implemented Interfaces:

Storable, java.lang.Cloneable

Direct Known Subclasses:

MaxPoolLink, MultiLink, SpikingLink

public class Link
extends BrainPart

An un/directed link from a source neuron to a sink neuron. If the directed flag is not set, source and sink are interchangeable.

Version:

$Id$

Author:

August Mayer, Helmut A. Mayer

Field Summary

Fields

Modifier and Type	Field and Description
protected Neuron	sink The destination / sink unit.
protected Neuron	source The source unit.
protected double	value The link value.

Fields inherited from class boone.BrainPart

activationFn, name, NO_ID, weight

Constructor Summary

Constructors

Constructor and Description
Link() Creates a directed link.
Link(double weight) Creates a dangling link with the given weight.
Link(Neuron source, Neuron sink, double weight) Creates a new link from source to sink with the given weight.

Method Summary

Modifier and Type	Method and Description
void	clearSink() Sets the sink to null.
void	clearSource() Sets the source to null.
Link	clone() Returns a semi-deep copy of this object.
void	disconnect() Disconnect this link, i.e.
void	fromXML(org.jdom2.Element element, NeuralNet net) Reads attributes from XML tree.
Neuron	getOtherNeuron(Neuron neuron) Get the other neuron of the link.
Neuron	getSink() Returns the sink neuron.
Neuron	getSource() Returns the source neuron.
double	getValue()
boolean	isDangling() Indicates a dangling link, i.e., a link not connecting neurons.
boolean	isDirected()
boolean	isInputOf(Neuron n) Indicates if this link is an input to the given neuron.
boolean	isOutputOf(Neuron n) Indicates if this link is an output of the given neuron.
void	propagate() Propagates the output of the source neuron over the link.
void	replaceFrom(Link oldLink) Replaces the given old link with this new link, i.e.
void	replaceNeuron(Neuron oldNeuron, Neuron newNeuron) Replace the given old neuron with a new neuron.
void	setDirected(boolean directed) Sets the direction flag.
Neuron	setSink(Neuron sink) Sets the link's sink neuron.
Neuron	setSource(Neuron source) Sets the link's source neuron.
void	setValue(double value)
java.lang.String	toString() Return a string
org.jdom2.Element	toXML(org.jdom2.Element element) Writes attributes to XML tree.

Methods inherited from class boone.BrainPart

addGradient, addToWeight, calculate, fromXML, getAccu, getActivationFn, getGradient, getID, getLastGradient, getName, getUniqueID, getWeight, isTrainable, randomize, randomize, reset, setAccu, setActivationFn, setGradient, setID, setLastGradient, setName, setTrainable, setWeight

Methods inherited from class java.lang.Object

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

Field Detail

source

protected Neuron source

The source unit.

sink

protected Neuron sink

The destination / sink unit.

value

protected double value

The link value.

Constructor Detail

Link

public Link()

Creates a directed link.

Link

public Link(double weight)

Creates a dangling link with the given weight.

Parameters:

weight - the weight value

Link

public Link(Neuron source,
            Neuron sink,
            double weight)

Creates a new link from source to sink with the given weight.

Parameters:

source - the source neuron

sink - the sink neuron

weight - the weight of this link

Method Detail

clone

public Link clone()

Returns a semi-deep copy of this object. Sets the ID of the clone to NO_ID. Sets the source and sink neuron of the clone to null. Note that the name is a reference to the name of this link.

Overrides:

clone in class BrainPart

Returns:

a semi-deep clone

getSource

public Neuron getSource()

Returns the source neuron.

Returns:

the neuron propagating signals over this link

setSource

public Neuron setSource(Neuron source)

Sets the link's source neuron. The involved neurons' link lists are updated.

Parameters:

source - the new source of the link, may be null

Returns:

the old source, may be null

clearSource

public void clearSource()

Sets the source to null.

getSink

public Neuron getSink()

Returns the sink neuron.

Returns:

the neuron signals are propagated to over this link

setSink

public Neuron setSink(Neuron sink)

Sets the link's sink neuron. The involved neurons' link lists are updated.

Parameters:

sink - the new sink of the link, may be null

Returns:

the old sink, may be null

clearSink

public void clearSink()

Sets the sink to null.

isDangling

public boolean isDangling()

Indicates a dangling link, i.e., a link not connecting neurons.

Returns:

true, if dangling

getValue

public double getValue()

Returns:

Value of property value.

setValue

public void setValue(double value)

Parameters:

value - New value of property value.

isDirected

public boolean isDirected()

Returns:

whether this link is directed.

setDirected

public void setDirected(boolean directed)

Sets the direction flag.

Parameters:

directed - true, otherwise both directions

disconnect

public void disconnect()

Disconnect this link, i.e. remove from the source and sink neurons.

NOTE: You also need to remove the Link object itself from the Neural Network; better use NeuralNet.removeLink(Link) instead.

propagate

public void propagate()

Propagates the output of the source neuron over the link.

getOtherNeuron

public Neuron getOtherNeuron(Neuron neuron)

Get the other neuron of the link. Especially interesting with directed links. If the given neuron is neither source nor sink, this function returns null. This comparison uses the == operator, testing for object identity.

Parameters:

neuron - the one neuron

Returns:

the other neuron. For example, if the given neuron is the source neuron, this returns the sink neuron.

replaceNeuron

public void replaceNeuron(Neuron oldNeuron,
                          Neuron newNeuron)

Replace the given old neuron with a new neuron. It doesn't matter whether the neuron to be replaced is the source or sink neuron. If the old neuron is neither the source or the sink neuron. this method does nothing.

Parameters:

oldNeuron - The neuron that is to be replaced.

newNeuron - The neuron that should be put into place instead of the old neuron.

replaceFrom

public void replaceFrom(Link oldLink)

Replaces the given old link with this new link, i.e. initialize source and sink neurons. Also sets the old neuron's source and sink neuron pointers to null.

isInputOf

public boolean isInputOf(Neuron n)

Indicates if this link is an input to the given neuron. Note that a link may be input and output link, i.e., a self-link.

Parameters:

n - a neuron

Returns:

true, if input link

isOutputOf

public boolean isOutputOf(Neuron n)

Indicates if this link is an output of the given neuron. Note that a link may be input and output link, i.e., a self-link.

Parameters:

n - a neuron

Returns:

true, if output link

toXML

public org.jdom2.Element toXML(org.jdom2.Element element)

Writes attributes to XML tree.

Specified by:

toXML in interface Storable

Overrides:

toXML in class BrainPart

Parameters:

element - the parent element

Returns:

the link element

fromXML

public void fromXML(org.jdom2.Element element,
                    NeuralNet net)

Reads attributes from XML tree.

Parameters:

element - an XML element

net - the associated net

toString

public java.lang.String toString()

Return a string

Overrides:

toString in class BrainPart