SQL Server LCHOOSE Function

Updated 2024-03-08 20:52:42.670000

Description

Use the scalar function LCHOOSE to calculate the natural logarithm of the binomial coefficient.

\text{LCHOOSE}=\ln\frac{n!}{(n-k)!k!}

SELECT [westclintech].[wct].[LCHOOSE](
  <@N, float,>
 ,<@K, float,>)

is any positive number. @N must be of a type float or of type that intrinsically converts to float.

is any positive number. @K must be of a type float or of a type that intrinsically converts to float.

float

@N is truncated and the integer value is used.

@K is truncated and the integer value is used.

If @N < 0 then NULL is returned.

If @K < 0 then NULL is returned.

If @K > @N then NULL is returned.

SELECT wct.LCHOOSE(   25, --@N
                      15  --@k
                  ) as LCHOOSE;

This produces the following result.

LCHOOSE
14.9999212660641

Using the EXP function with LCHOOSE will return the binomial coefficient.

SELECT EXP(wct.LCHOOSE(25, 15)) as LCHOOSE,
       wct.BICO(25, 15) as BICO;

This produces the following result.

LCHOOSE	BICO
3268759.99999999	3268760