Package org.apache.commons.numbers.combinatorics

Class LogBinomialCoefficient

java.lang.Object

org.apache.commons.numbers.combinatorics.LogBinomialCoefficient

public final class LogBinomialCoefficient
extends Object

Natural logarithm of the binomial coefficient. It is "n choose k", the number of k-element subsets that can be selected from an n-element set.

Method Summary

Modifier and Type	Method	Description
static double	value(int n, int k)	Computes the logarithm of the binomial coefficient.

Methods inherited from class java.lang.Object

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

Method Details

value

public static double value(int n,
 int k)

Computes the logarithm of the binomial coefficient.

This returns a finite result for any valid n choose k.

Parameters:

n - Size of the set.

k - Size of the subsets to be counted.

Returns:

log(n choose k).

Throws:

IllegalArgumentException - if n < 0, k < 0 or k > n.