cdef extern from "gsl/gsl_sf_gegenbauer.h": double gsl_sf_gegenpoly_1(double lambd, double x) double gsl_sf_gegenpoly_2(double lambd, double x) double gsl_sf_gegenpoly_3(double lambd, double x) int gsl_sf_gegenpoly_1_e(double lambd, double x, gsl_sf_result * result) int gsl_sf_gegenpoly_2_e(double lambd, double x, gsl_sf_result * result) int gsl_sf_gegenpoly_3_e(double lambd, double x, gsl_sf_result * result) double gsl_sf_gegenpoly_n(int n, double lambd, double x) int gsl_sf_gegenpoly_n_e(int n, double lambd, double x, gsl_sf_result * result) int gsl_sf_gegenpoly_array(int nmax, double lambd, double x, double result_array[])
