### Irregular Spherical Bessel Functions

Function: double gsl_sf_bessel_y0 (double x)
Function: int gsl_sf_bessel_y0_e (double x, gsl_sf_result * result)
These routines compute the irregular spherical Bessel function of zeroth order, @math{y_0(x) = -\cos(x)/x}.

Function: double gsl_sf_bessel_y1 (double x)
Function: int gsl_sf_bessel_y1_e (double x, gsl_sf_result * result)
These routines compute the irregular spherical Bessel function of first order, @math{y_1(x) = -(\cos(x)/x + \sin(x))/x}.

Function: double gsl_sf_bessel_y2 (double x)
Function: int gsl_sf_bessel_y2_e (double x, gsl_sf_result * result)
These routines compute the irregular spherical Bessel function of second order, @math{y_2(x) = (-3/x^2 + 1/x)\cos(x) - (3/x^2)\sin(x)}.

Function: double gsl_sf_bessel_yl (int l, double x)
Function: int gsl_sf_bessel_yl_e (int l, double x, gsl_sf_result * result)
These routines compute the irregular spherical Bessel function of order l, @math{y_l(x)}, for @c{$l \geq 0$} @math{l >= 0}.

Function: int gsl_sf_bessel_yl_array (int lmax, double x, double result_array[])
This routine computes the values of the irregular spherical Bessel functions @math{y_l(x)} for @math{l} from 0 to lmax inclusive for @c{$lmax \geq 0$} @math{lmax >= 0}, storing the results in the array result_array. The values are computed using recurrence relations, for efficiency, and therefore may differ slightly from the exact values.