smile.math.distance

Class EuclideanDistance

java.lang.Object

smile.math.distance.EuclideanDistance

All Implemented Interfaces:

Distance<double[]>, Metric<double[]>

public class EuclideanDistance
extends Object
implements Metric<double[]>

Euclidean distance. Use getInstance() to get the standard unweighted Euclidean distance. Or create an instance with a specified weight vector. For float or double arrays, missing values (i.e. NaN) are also handled. Also support sparse arrays of which zeros are excluded to save space.

Author:

Haifeng Li

Constructor Summary

Constructors

Constructor and Description
EuclideanDistance() Constructor.
EuclideanDistance(double[] weight) Constructor with a given weight vector.

Method Summary

Methods

Modifier and Type	Method and Description
double	d(double[] x, double[] y) Euclidean distance between the two arrays of type double.
double	d(float[] x, float[] y) Euclidean distance between the two arrays of type float.
double	d(int[] x, int[] y) Euclidean distance between the two arrays of type integer.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

EuclideanDistance

public EuclideanDistance()

Constructor. Standard (unweighted) Euclidean distance.

EuclideanDistance

public EuclideanDistance(double[] weight)

Constructor with a given weight vector.

Parameters:

weight - the weight vector.

Method Detail

toString

public String toString()

Overrides:

toString in class Object

d

public double d(int[] x,
       int[] y)

Euclidean distance between the two arrays of type integer. No missing value handling in this method.

d

public double d(float[] x,
       float[] y)

Euclidean distance between the two arrays of type float. NaN will be treated as missing values and will be excluded from the calculation. Let m be the number nonmissing values, and n be the number of all values. The returned distance is sqrt(n * d / m), where d is the square of distance between nonmissing values.

d

public double d(double[] x,
       double[] y)

Euclidean distance between the two arrays of type double. NaN will be treated as missing values and will be excluded from the calculation. Let m be the number nonmissing values, and n be the number of all values. The returned distance is sqrt(n * d / m), where d is the square of distance between nonmissing values.

Specified by:

d in interface Distance<double[]>