Package org.apache.commons.math4.neuralnet.twod

Class NeuronSquareMesh2D

java.lang.Object

org.apache.commons.math4.neuralnet.twod.NeuronSquareMesh2D

All Implemented Interfaces:

Iterable<Neuron>

public class NeuronSquareMesh2D
extends Object
implements Iterable<Neuron>

Neural network with the topology of a two-dimensional surface. Each neuron defines one surface element.
This network is primarily intended to represent a Self Organizing Feature Map.

Since:

3.3

See Also:

org.apache.commons.math4.neuralnet.sofm

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	NeuronSquareMesh2D.DataVisualization	Miscellaneous indicators of the map quality.
static class	NeuronSquareMesh2D.HorizontalDirection	Horizontal (along row) direction.
static class	NeuronSquareMesh2D.VerticalDirection	Vertical (along column) direction.

Constructor Summary

Constructors

Constructor	Description
NeuronSquareMesh2D(boolean wrapRowDim, boolean wrapColDim, SquareNeighbourhood neighbourhoodType, double[][][] featuresList)
NeuronSquareMesh2D(int numRows, boolean wrapRowDim, int numCols, boolean wrapColDim, SquareNeighbourhood neighbourhoodType, FeatureInitializer[] featureInit)	Creates a two-dimensional network composed of square cells: Each neuron not located on the border of the mesh has four neurons linked to it.

Method Summary

Modifier and Type	Method	Description
NeuronSquareMesh2D.DataVisualization	computeQualityIndicators(Iterable<double[]> data)	Computes various indicators of the quality of the representation of the given data by this map.
NeuronSquareMesh2D	copy()	Performs a deep copy of this instance.
Network	getNetwork()	Retrieves the underlying network.
Neuron	getNeuron(int i, int j)	Retrieves the neuron at location (i, j) in the map.
Neuron	getNeuron(int row, int col, NeuronSquareMesh2D.HorizontalDirection alongRowDir, NeuronSquareMesh2D.VerticalDirection alongColDir)	Retrieves the requested neuron relative to the given (row, col) position.
int	getNumberOfColumns()	Gets the number of neurons in each column of this map.
int	getNumberOfRows()	Gets the number of neurons in each row of this map.
SquareNeighbourhood	getSquareNeighbourhood()	Indicates the type of connectivity between neurons.
boolean	isWrappedColumn()	Indicates whether the map is wrapped along the second dimension.
boolean	isWrappedRow()	Indicates whether the map is wrapped along the first dimension.
Iterator<Neuron>	iterator()

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

Constructor Detail

NeuronSquareMesh2D

public NeuronSquareMesh2D(boolean wrapRowDim,
                          boolean wrapColDim,
                          SquareNeighbourhood neighbourhoodType,
                          double[][][] featuresList)

Parameters:

wrapRowDim - Whether to wrap the first dimension (i.e the first and last neurons will be linked together).

wrapColDim - Whether to wrap the second dimension (i.e the first and last neurons will be linked together).

neighbourhoodType - Neighbourhood type.

featuresList - Arrays that will initialize the features sets of the network's neurons.

Throws:

IllegalArgumentException - if numRows < 2 or numCols < 2.

NeuronSquareMesh2D

public NeuronSquareMesh2D(int numRows,
                          boolean wrapRowDim,
                          int numCols,
                          boolean wrapColDim,
                          SquareNeighbourhood neighbourhoodType,
                          FeatureInitializer[] featureInit)

Creates a two-dimensional network composed of square cells: Each neuron not located on the border of the mesh has four neurons linked to it.
The links are bi-directional.
The topology of the network can also be a cylinder (if one of the dimensions is wrapped) or a torus (if both dimensions are wrapped).

Parameters:

numRows - Number of neurons in the first dimension.

wrapRowDim - Whether to wrap the first dimension (i.e the first and last neurons will be linked together).

numCols - Number of neurons in the second dimension.

wrapColDim - Whether to wrap the second dimension (i.e the first and last neurons will be linked together).

neighbourhoodType - Neighbourhood type.

featureInit - Array of functions that will initialize the corresponding element of the features set of each newly created neuron. In particular, the size of this array defines the size of feature set.

Throws:

IllegalArgumentException - if numRows < 2 or numCols < 2.

Method Detail

copy

public NeuronSquareMesh2D 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 Iterator<Neuron> iterator()

Specified by:

iterator in interface Iterable<Neuron>

getNetwork

public Network getNetwork()

Retrieves the underlying network. A reference is returned (enabling, for example, the network to be trained). This also implies that calling methods that modify the Network topology may cause this class to become inconsistent.

Returns:

the network.

getNumberOfRows

public int getNumberOfRows()

Gets the number of neurons in each row of this map.

Returns:

the number of rows.

getNumberOfColumns

public int getNumberOfColumns()

Gets the number of neurons in each column of this map.

Returns:

the number of column.

isWrappedRow

public boolean isWrappedRow()

Indicates whether the map is wrapped along the first dimension.

Returns:

true if the last neuron of a row is linked to the first neuron of that row.

isWrappedColumn

public boolean isWrappedColumn()

Indicates whether the map is wrapped along the second dimension.

Returns:

true if the last neuron of a column is linked to the first neuron of that column.

getSquareNeighbourhood

public SquareNeighbourhood getSquareNeighbourhood()

Indicates the type of connectivity between neurons.

Returns:

the neighbourhood type.

getNeuron

public Neuron getNeuron(int i,
                        int j)

Retrieves the neuron at location (i, j) in the map. The neuron at position (0, 0) is located at the upper-left corner of the map.

Parameters:

i - Row index.

j - Column index.

Returns:

the neuron at (i, j).

Throws:

IllegalArgumentException - if i or j is out of range.

See Also:

getNeuron(int,int,HorizontalDirection,VerticalDirection)

getNeuron

public Neuron getNeuron(int row,
                        int col,
                        NeuronSquareMesh2D.HorizontalDirection alongRowDir,
                        NeuronSquareMesh2D.VerticalDirection alongColDir)

Retrieves the requested neuron relative to the given (row, col) position. The neuron at position (0, 0) is located at the upper-left corner of the map.

Parameters:

row - Row index.

col - Column index.

alongRowDir - Direction along the given row (i.e. an offset will be added to the given column index.

alongColDir - Direction along the given col (i.e. an offset will be added to the given row index.

Returns:

the neuron at the requested location, or null if the location is not on the map.

See Also:

getNeuron(int,int)

computeQualityIndicators

public NeuronSquareMesh2D.DataVisualization computeQualityIndicators(Iterable<double[]> data)

Computes various indicators of the quality of the representation of the given data by this map.

Parameters:

data - Features.

Returns:

a new instance holding quality indicators.