NMath User's Guide

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39.1 Combinatorial Functions (.NET, C#, CSharp, VB, Visual Basic, F#)

The static Factorial() method on class StatsFunctions returns n!, the number of ways that n objects can be permuted. A lookup table is used for for faster access. For example:

Code Example – C# factorial

int i = StatsFunctions.Factorial( 20 );
// i = 2,432,902,008,176,640,000

FactorialLn() returns the natural log factorial of n, .

The static Binomial() method returns the binomial coefficient. The binomial coefficient ("choose m") is the number of ways of picking m unordered outcomes from n possibilities:


For instance:

Code Example – C# binomial

int nCm = StatsFunctions.Binomial( 6, 4 );

BinomialLn() returns the natural log of the binomial coefficient.