.. index::

   single: Jacobi elliptic functions

   single: elliptic functions (Jacobi)

The Jacobian Elliptic functions are defined in Abramowitz & Stegun,

Chapter 16.  The functions are declared in the header file

:file:`gsl_sf_elljac.h`.

.. function:: int gsl_sf_elljac_e (double u, double m, double * sn, double * cn, double * dn)

   This function computes the Jacobian elliptic functions :math:`sn(u|m)`,

   :math:`cn(u|m)`, :math:`dn(u|m)` by descending Landen

   transformations.

.. Exceptional Return Values: GSL_EDOM