— Function: int gsl_sf_mathieu_ce (int n, double q, double x, gsl_sf_result * result)
— Function: int gsl_sf_mathieu_se (int n, double q, double x, gsl_sf_result * result)

These routines compute the angular Mathieu functions ce_n(q,x) and se_n(q,x), respectively.

— Function: int gsl_sf_mathieu_ce_array (int nmin, int nmax, double q, double x, gsl_sf_mathieu_workspace * work, double result_array[])
— Function: int gsl_sf_mathieu_se_array (int nmin, int nmax, double q, double x, gsl_sf_mathieu_workspace * work, double result_array[])

These routines compute a series of the angular Mathieu functions ce_n(q,x) and se_n(q,x) of order n from nmin to nmax inclusive, storing the results in the array result_array.