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/* specfunc/bessel.h
*
* Copyright (C) 1996, 1997, 1998, 1999, 2000 Gerard Jungman
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/* Author: G. Jungman */
#ifndef _BESSEL_H_
#define _BESSEL_H_
#include <gsl/gsl_sf_result.h>
/* Taylor expansion for J_nu(x) or I_nu(x)
* sign = -1 ==> Jnu
* sign = +1 ==> Inu
*/
int gsl_sf_bessel_IJ_taylor_e(const double nu, const double x,
const int sign,
const int kmax,
const double threshold,
gsl_sf_result * result
);
int gsl_sf_bessel_Jnu_asympx_e(const double nu, const double x, gsl_sf_result * result);
int gsl_sf_bessel_Ynu_asympx_e(const double nu, const double x, gsl_sf_result * result);
int gsl_sf_bessel_Inu_scaled_asympx_e(const double nu, const double x, gsl_sf_result * result);
int gsl_sf_bessel_Knu_scaled_asympx_e(const double nu, const double x, gsl_sf_result * result);
int gsl_sf_bessel_Inu_scaled_asymp_unif_e(const double nu, const double x, gsl_sf_result * result);
int gsl_sf_bessel_Knu_scaled_asymp_unif_e(const double nu, const double x, gsl_sf_result * result);
/* ratio = J_{nu+1}(x) / J_nu(x)
* sgn = sgn(J_nu(x))
*/
int
gsl_sf_bessel_J_CF1(const double nu, const double x, double * ratio, double * sgn);
/* ratio = I_{nu+1}(x) / I_nu(x)
*/
int
gsl_sf_bessel_I_CF1_ser(const double nu, const double x, double * ratio);
/* Evaluate the Steed method continued fraction CF2 for
*
* (J' + i Y')/(J + i Y) := P + i Q
*/
int
gsl_sf_bessel_JY_steed_CF2(const double nu, const double x,
double * P, double * Q);
int
gsl_sf_bessel_JY_mu_restricted(const double mu, const double x,
gsl_sf_result * Jmu, gsl_sf_result * Jmup1,
gsl_sf_result * Ymu, gsl_sf_result * Ymup1);
int
gsl_sf_bessel_K_scaled_steed_temme_CF2(const double nu, const double x,
double * K_nu, double * K_nup1,
double * Kp_nu);
/* These are of use in calculating the oscillating
* Bessel functions.
* cos(y - pi/4 + eps)
* sin(y - pi/4 + eps)
*/
int gsl_sf_bessel_cos_pi4_e(double y, double eps, gsl_sf_result * result);
int gsl_sf_bessel_sin_pi4_e(double y, double eps, gsl_sf_result * result);
#endif /* !_BESSEL_H_ */