smile.stat

Class GoodTuring

java.lang.Object

smile.stat.GoodTuring

public class GoodTuring
extends java.lang.Object

Good–Turing frequency estimation. This technique is for estimating the probability of encountering an object of a hitherto unseen species, given a set of past observations of objects from different species. In drawing balls from an urn, the 'objects' would be balls and the 'species' would be the distinct colors of the balls (finite but unknown in number). After drawing R_red red balls, R_black black balls and , R_green green balls, we would ask what is the probability of drawing a red ball, a black ball, a green ball or one of a previously unseen color.

This method takes a set of (frequency, frequency-of-frequency) pairs and estimate the probabilities corresponding to the observed frequencies, and P₀, the joint probability of all unobserved species.

Field Summary

Fields

Modifier and Type	Field and Description
double[]	p The probabilities corresponding to the observed frequencies.
double	p0 The joint probability of all unobserved species.

Method Summary

Modifier and Type	Method and Description
static GoodTuring	of(int[] r, int[] Nr) Good–Turing frequency estimation.

Methods inherited from class java.lang.Object

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

Field Detail

p

public final double[] p

The probabilities corresponding to the observed frequencies.

p0

public final double p0

The joint probability of all unobserved species.

Method Detail

of

public static GoodTuring of(int[] r,
                            int[] Nr)

Good–Turing frequency estimation.

Parameters:

r - the frequency in ascending order.

Nr - the frequency of frequencies.

Returns:

the estimation object.