Package org.apache.commons.math4.neuralnet

Class MapUtils

java.lang.Object

org.apache.commons.math4.neuralnet.MapUtils

public final class MapUtils
extends Object

Utilities for network maps.

Since:

3.3

Method Summary

Modifier and Type	Method	Description
static double	computeQuantizationError(Iterable<double[]> data, Iterable<Neuron> neurons, DistanceMeasure distance)	Computes the quantization error.
static double	computeTopographicError(Iterable<double[]> data, Network net, DistanceMeasure distance)	Computes the topographic error.

Methods inherited from class java.lang.Object

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

Method Detail

computeQuantizationError

public static double computeQuantizationError(Iterable<double[]> data,
                                              Iterable<Neuron> neurons,
                                              DistanceMeasure distance)

Computes the quantization error. The quantization error is the average distance between a feature vector and its "best matching unit" (closest neuron).

Parameters:

data - Feature vectors.

neurons - List of neurons to scan.

distance - Distance function.

Returns:

the error.

Throws:

IllegalArgumentException - if data is empty.

computeTopographicError

public static double computeTopographicError(Iterable<double[]> data,
                                             Network net,
                                             DistanceMeasure distance)

Computes the topographic error. The topographic error is the proportion of data for which first and second best matching units are not adjacent in the map.

Parameters:

data - Feature vectors.

net - Network.

distance - Distance function.

Returns:

the error.

Throws:

IllegalArgumentException - if data is empty.