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 
("n 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.