Package org.apache.commons.math3.ml.neuralnet

Class Network

java.lang.Object

org.apache.commons.math3.ml.neuralnet.Network

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<Neuron>

public class Network
extends java.lang.Object
implements java.lang.Iterable<Neuron>, java.io.Serializable

Neural network, composed of Neuron instances and the links between them. Although updating a neuron's state is thread-safe, modifying the network's topology (adding or removing links) is not.

Since:

3.3

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Network.NeuronIdentifierComparator	Comparator that prescribes an order of the neurons according to the increasing order of their identifier.
private static class	Network.SerializationProxy	Serialization.

Field Summary

Fields

Modifier and Type	Field	Description
private int	featureSize	Neuron's features set size.
private java.util.concurrent.ConcurrentHashMap<java.lang.Long,java.util.Set<java.lang.Long>>	linkMap	Links.
private java.util.concurrent.ConcurrentHashMap<java.lang.Long,Neuron>	neuronMap	Neurons.
private java.util.concurrent.atomic.AtomicLong	nextId	Next available neuron identifier.
private static long	serialVersionUID	Serializable.

Constructor Summary

Constructors

Constructor	Description
Network(long initialIdentifier, int featureSize)
Network(long nextId, int featureSize, Neuron[] neuronList, long[][] neighbourIdList)	Constructor with restricted access, solely used for deserialization.

Method Summary

Modifier and Type	Method	Description
void	addLink(Neuron a, Neuron b)	Adds a link from neuron a to neuron b.
private void	addLinkToLinkSet(java.util.Set<java.lang.Long> linkSet, long id)	Adds a link to neuron id in given linkSet.
Network	copy()	Performs a deep copy of this instance.
long	createNeuron(double[] features)	Creates a neuron and assigns it a unique identifier.
private java.lang.Long	createNextId()	Creates a neuron identifier.
void	deleteLink(Neuron a, Neuron b)	Deletes the link between neurons a and b.
private void	deleteLinkFromLinkSet(java.util.Set<java.lang.Long> linkSet, long id)	Deletes a link to neuron id in given linkSet.
void	deleteNeuron(Neuron neuron)	Deletes a neuron.
int	getFeaturesSize()	Gets the size of the neurons' features set.
java.util.Collection<Neuron>	getNeighbours(java.lang.Iterable<Neuron> neurons)	Retrieves the neurons in the neighbourhood of any neuron in the neurons list.
java.util.Collection<Neuron>	getNeighbours(java.lang.Iterable<Neuron> neurons, java.lang.Iterable<Neuron> exclude)	Retrieves the neurons in the neighbourhood of any neuron in the neurons list.
java.util.Collection<Neuron>	getNeighbours(Neuron neuron)	Retrieves the neighbours of the given neuron.
java.util.Collection<Neuron>	getNeighbours(Neuron neuron, java.lang.Iterable<Neuron> exclude)	Retrieves the neighbours of the given neuron.
Neuron	getNeuron(long id)	Retrieves the neuron with the given (unique) id.
java.util.Collection<Neuron>	getNeurons(java.util.Comparator<Neuron> comparator)	Creates a list of the neurons, sorted in a custom order.
java.util.Iterator<Neuron>	iterator()
private void	readObject(java.io.ObjectInputStream in)	Prevents proxy bypass.
private java.lang.Object	writeReplace()	Custom serialization.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

serialVersionUID

private static final long serialVersionUID

Serializable.

See Also:

Constant Field Values

neuronMap

private final java.util.concurrent.ConcurrentHashMap<java.lang.Long,Neuron> neuronMap

Neurons.

nextId

private final java.util.concurrent.atomic.AtomicLong nextId

Next available neuron identifier.

featureSize

private final int featureSize

Neuron's features set size.

linkMap

private final java.util.concurrent.ConcurrentHashMap<java.lang.Long,java.util.Set<java.lang.Long>> linkMap

Links.

Constructor Detail

Network

Network(long nextId,
        int featureSize,
        Neuron[] neuronList,
        long[][] neighbourIdList)

Constructor with restricted access, solely used for deserialization.

Parameters:

nextId - Next available identifier.

featureSize - Number of features.

neuronList - Neurons.

neighbourIdList - Links associated to each of the neurons in neuronList.

Throws:

MathIllegalStateException - if an inconsistency is detected (which probably means that the serialized form has been corrupted).

Network

public Network(long initialIdentifier,
               int featureSize)

Parameters:

initialIdentifier - Identifier for the first neuron that will be added to this network.

featureSize - Size of the neuron's features.

Method Detail

copy

public Network copy()

Performs a deep copy of this instance. Upon return, the copied and original instances will be independent: Updating one will not affect the other.

Returns:

a new instance with the same state as this instance.

Since:

3.6

iterator

public java.util.Iterator<Neuron> iterator()

Specified by:

iterator in interface java.lang.Iterable<Neuron>

getNeurons

public java.util.Collection<Neuron> getNeurons(java.util.Comparator<Neuron> comparator)

Creates a list of the neurons, sorted in a custom order.

Parameters:

comparator - Comparator used for sorting the neurons.

Returns:

a list of neurons, sorted in the order prescribed by the given comparator.

See Also:

Network.NeuronIdentifierComparator

createNeuron

public long createNeuron(double[] features)

Creates a neuron and assigns it a unique identifier.

Parameters:

features - Initial values for the neuron's features.

Returns:

the neuron's identifier.

Throws:

DimensionMismatchException - if the length of features is different from the expected size (as set by the constructor).

deleteNeuron

public void deleteNeuron(Neuron neuron)

Deletes a neuron. Links from all neighbours to the removed neuron will also be deleted.

Parameters:

neuron - Neuron to be removed from this network.

Throws:

java.util.NoSuchElementException - if n does not belong to this network.

getFeaturesSize

public int getFeaturesSize()

Gets the size of the neurons' features set.

Returns:

the size of the features set.

addLink

public void addLink(Neuron a,
                    Neuron b)

Adds a link from neuron a to neuron b. Note: the link is not bi-directional; if a bi-directional link is required, an additional call must be made with a and b exchanged in the argument list.

Parameters:

a - Neuron.

b - Neuron.

Throws:

java.util.NoSuchElementException - if the neurons do not exist in the network.

addLinkToLinkSet

private void addLinkToLinkSet(java.util.Set<java.lang.Long> linkSet,
                              long id)

Adds a link to neuron id in given linkSet. Note: no check verifies that the identifier indeed belongs to this network.

Parameters:

linkSet - Neuron identifier.

id - Neuron identifier.

deleteLink

public void deleteLink(Neuron a,
                       Neuron b)

Deletes the link between neurons a and b.

Parameters:

a - Neuron.

b - Neuron.

Throws:

java.util.NoSuchElementException - if the neurons do not exist in the network.

deleteLinkFromLinkSet

private void deleteLinkFromLinkSet(java.util.Set<java.lang.Long> linkSet,
                                   long id)

Deletes a link to neuron id in given linkSet. Note: no check verifies that the identifier indeed belongs to this network.

Parameters:

linkSet - Neuron identifier.

id - Neuron identifier.

getNeuron

public Neuron getNeuron(long id)

Retrieves the neuron with the given (unique) id.

Parameters:

id - Identifier.

Returns:

the neuron associated with the given id.

Throws:

java.util.NoSuchElementException - if the neuron does not exist in the network.

getNeighbours

public java.util.Collection<Neuron> getNeighbours(java.lang.Iterable<Neuron> neurons)

Retrieves the neurons in the neighbourhood of any neuron in the neurons list.

Parameters:

neurons - Neurons for which to retrieve the neighbours.

Returns:

the list of neighbours.

See Also:

getNeighbours(Iterable,Iterable)

getNeighbours

public java.util.Collection<Neuron> getNeighbours(java.lang.Iterable<Neuron> neurons,
                                                  java.lang.Iterable<Neuron> exclude)

Retrieves the neurons in the neighbourhood of any neuron in the neurons list. The exclude list allows to retrieve the "concentric" neighbourhoods by removing the neurons that belong to the inner "circles".

Parameters:

neurons - Neurons for which to retrieve the neighbours.

exclude - Neurons to exclude from the returned list. Can be null.

Returns:

the list of neighbours.

getNeighbours

public java.util.Collection<Neuron> getNeighbours(Neuron neuron)

Retrieves the neighbours of the given neuron.

Parameters:

neuron - Neuron for which to retrieve the neighbours.

Returns:

the list of neighbours.

See Also:

getNeighbours(Neuron,Iterable)

getNeighbours

public java.util.Collection<Neuron> getNeighbours(Neuron neuron,
                                                  java.lang.Iterable<Neuron> exclude)

Retrieves the neighbours of the given neuron.

Parameters:

neuron - Neuron for which to retrieve the neighbours.

exclude - Neurons to exclude from the returned list. Can be null.

Returns:

the list of neighbours.

createNextId

private java.lang.Long createNextId()

Creates a neuron identifier.

Returns:

a value that will serve as a unique identifier.

readObject

private void readObject(java.io.ObjectInputStream in)

Prevents proxy bypass.

Parameters:

in - Input stream.

writeReplace

private java.lang.Object writeReplace()

Custom serialization.

Returns:

the proxy instance that will be actually serialized.