4.1 Combinatorial Functions

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:

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 ("n choose m") is the number of ways of picking m unordered outcomes from n possibilities:

For instance:

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

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