1 @cindex Gegenbauer functions
3 The Gegenbauer polynomials are defined in Abramowitz & Stegun, Chapter
4 22, where they are known as Ultraspherical polynomials. The functions
5 described in this section are declared in the header file
6 @file{gsl_sf_gegenbauer.h}.
8 @deftypefun double gsl_sf_gegenpoly_1 (double @var{lambda}, double @var{x})
9 @deftypefunx double gsl_sf_gegenpoly_2 (double @var{lambda}, double @var{x})
10 @deftypefunx double gsl_sf_gegenpoly_3 (double @var{lambda}, double @var{x})
11 @deftypefunx int gsl_sf_gegenpoly_1_e (double @var{lambda}, double @var{x}, gsl_sf_result * @var{result})
12 @deftypefunx int gsl_sf_gegenpoly_2_e (double @var{lambda}, double @var{x}, gsl_sf_result * @var{result})
13 @deftypefunx int gsl_sf_gegenpoly_3_e (double @var{lambda}, double @var{x}, gsl_sf_result * @var{result})
14 These functions evaluate the Gegenbauer polynomials
15 @c{$C^{(\lambda)}_n(x)$}
16 @math{C^@{(\lambda)@}_n(x)} using explicit
17 representations for @math{n =1, 2, 3}.
18 @comment Exceptional Return Values: none
22 @deftypefun double gsl_sf_gegenpoly_n (int @var{n}, double @var{lambda}, double @var{x})
23 @deftypefunx int gsl_sf_gegenpoly_n_e (int @var{n}, double @var{lambda}, double @var{x}, gsl_sf_result * @var{result})
24 These functions evaluate the Gegenbauer polynomial @c{$C^{(\lambda)}_n(x)$}
25 @math{C^@{(\lambda)@}_n(x)} for a specific value of @var{n},
26 @var{lambda}, @var{x} subject to @math{\lambda > -1/2}, @c{$n \ge 0$}
28 @comment Domain: lambda > -1/2, n >= 0
29 @comment Exceptional Return Values: GSL_EDOM
33 @deftypefun int gsl_sf_gegenpoly_array (int @var{nmax}, double @var{lambda}, double @var{x}, double @var{result_array}[])
34 This function computes an array of Gegenbauer polynomials
35 @c{$C^{(\lambda)}_n(x)$}
36 @math{C^@{(\lambda)@}_n(x)} for @math{n = 0, 1, 2, \dots, nmax}, subject
37 to @math{\lambda > -1/2}, @c{$nmax \ge 0$}
39 @comment Conditions: n = 0, 1, 2, ... nmax
40 @comment Domain: lambda > -1/2, nmax >= 0
41 @comment Exceptional Return Values: GSL_EDOM