Returns the binomial coefficient defined as:
\begin{equation}
  \binom{n}{k} = \frac{n!}{k! (n-k)!} \text{ for } 0 \le k \le n
\end{equation}
where $n$ and $k$ are the first and second arguments, respectively.

The routine can be used for example to construct the Pascal's trangle\index{Pascal's triangle}:
\gdlcodeexample{imsl_binomialcoef_0}{}{imsl_binomialcoef}
\gdlkeyworddesc{DOUBLE}
Forces double precision:
\gdlcodeexample{imsl_binomialcoef_1}{imsl_binomialcoef,double}{}
\gdlimplmtndtls{this routine is a wrapper to the GSL's gsl\_sf\_choose() function \citep{bib_GSL}}
\gdlimsldisclaimer
