www.gusucode.com > elfun18工具箱matlab源码程序 > elfun18/elfun18v1_3/elfun18v1_2/elfun18/jdn.m

    function result = jdn( x, k)
%JDN Compute value of the Jacobi elliptic function dn(x,k) for
%   argument |x|<inf and elliptic modulus |k|<inf. Returns NaN if any of
%   the arguments is invalid or convergence failed. It is assumed that 
%   arguments are real scalars without check.
%
%   Functions called:
%       sncndn
%

    [~, ~, result] = sncndn( x, (1 - k)*(1 + k));

end