@cindex Debye functionsThe Debye functions are defined by the integral @math{D_n(x) = n/x^n\int_0^x dt (t^n/(e^t - 1))}.  For further information see Abramowitz &Stegun, Section 27.1.  The Debye functions are declared in the headerfile @file{gsl_sf_debye.h}.@deftypefun double gsl_sf_debye_1 (double @var{x})@deftypefunx int gsl_sf_debye_1_e (double @var{x}, gsl_sf_result * @var{result})These routines compute the first-order Debye function @math{D_1(x) = (1/x) \int_0^x dt (t/(e^t - 1))}.@comment Exceptional Return Values: GSL_EDOM@end deftypefun@deftypefun double gsl_sf_debye_2 (double @var{x})@deftypefunx int gsl_sf_debye_2_e (double @var{x}, gsl_sf_result * @var{result})These routines compute the second-order Debye function @math{D_2(x) = (2/x^2) \int_0^x dt (t^2/(e^t - 1))}.@comment Exceptional Return Values: GSL_EDOM, GSL_EUNDRFLW@end deftypefun@deftypefun double gsl_sf_debye_3 (double @var{x})@deftypefunx int gsl_sf_debye_3_e (double @var{x}, gsl_sf_result * @var{result})These routines compute the third-order Debye function @math{D_3(x) = (3/x^3) \int_0^x dt (t^3/(e^t - 1))}.@comment Exceptional Return Values: GSL_EDOM, GSL_EUNDRFLW@end deftypefun@deftypefun double gsl_sf_debye_4 (double @var{x})@deftypefunx int gsl_sf_debye_4_e (double @var{x}, gsl_sf_result * @var{result})These routines compute the fourth-order Debye function @math{D_4(x) = (4/x^4) \int_0^x dt (t^4/(e^t - 1))}.@comment Exceptional Return Values: GSL_EDOM, GSL_EUNDRFLW@end deftypefun