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.. index::
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single: Laguerre functions
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single: confluent hypergeometric function
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The generalized Laguerre polynomials, sometimes referred to as
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associated Laguerre polynomials, are defined in terms of confluent
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hypergeometric functions as
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.. only:: not texinfo
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.. math:: L^a_n(x) = {(a+1)_n \over n!} {}_1F_1(-n,a+1,x)
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.. only:: texinfo
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L^a_n(x) = ((a+1)_n / n!) 1F1(-n,a+1,x)
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where :math:`(a)_n` is the :ref:`Pochhammer symbol <pochhammer-symbol>` (rising factorial).
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They are related to the plain
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Laguerre polynomials :math:`L_n(x)` by :math:`L^0_n(x) = L_n(x)` and
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:math:`L^k_n(x) = (-1)^k (d^k/dx^k) L_{(n+k)}(x)`
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For more information see Abramowitz & Stegun, Chapter 22.
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The functions described in this section are
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declared in the header file :file:`gsl_sf_laguerre.h`.
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.. function:: double gsl_sf_laguerre_1 (double a, double x)
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double gsl_sf_laguerre_2 (double a, double x)
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double gsl_sf_laguerre_3 (double a, double x)
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int gsl_sf_laguerre_1_e (double a, double x, gsl_sf_result * result)
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int gsl_sf_laguerre_2_e (double a, double x, gsl_sf_result * result)
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int gsl_sf_laguerre_3_e (double a, double x, gsl_sf_result * result)
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These routines evaluate the generalized Laguerre polynomials
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:math:`L^a_1(x)`, :math:`L^a_2(x)`, :math:`L^a_3(x)` using explicit
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representations.
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.. Exceptional Return Values: none
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.. function:: double gsl_sf_laguerre_n (const int n, const double a, const double x)
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int gsl_sf_laguerre_n_e (int n, double a, double x, gsl_sf_result * result)
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These routines evaluate the generalized Laguerre polynomials
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:math:`L^a_n(x)` for :math:`a > -1`,
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:math:`n \ge 0`.
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.. Domain: a > -1.0, n >= 0
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.. Evaluate generalized Laguerre polynomials.
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.. Exceptional Return Values: GSL_EDOM
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