% -*- texinfo -*-
% @deftypefn {Mapping Function} {} betaln (@var{a}, @var{b})
% Return the log of the Beta function,
% @tex
% $$
% B (a, b) = \log {\Gamma (a) \Gamma (b) \over \Gamma (a + b)}.
% $$
% @end tex
% @ifnottex
%
% @example
% betaln (a, b) = gammaln (a) + gammaln (b) - gammaln (a + b)
% @end example
% @end ifnottex
% @seealso{beta, betainc, gammaln}
% @end deftypefn