.. 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