text: /* specfunc/gsl_sf_lambert.h
   * 
   * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001 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 __GSL_SF_LAMBERT_H__
  #define __GSL_SF_LAMBERT_H__
  
  #include <gsl/gsl_sf_result.h>
  #include <gsl/gsl_types.h>
  
  #undef __BEGIN_DECLS
  #undef __END_DECLS
  #ifdef __cplusplus
  # define __BEGIN_DECLS extern "C" {
  # define __END_DECLS }
  #else
  # define __BEGIN_DECLS /* empty */
  # define __END_DECLS /* empty */
  #endif
  
  __BEGIN_DECLS
  
  
  /* Lambert's Function W_0(x)
   *
   * W_0(x) is the principal branch of the
   * implicit function defined by W e^W = x.
   *
   * -1/E < x < \infty
   *
   * exceptions: GSL_EMAXITER;
   */
  GSL_EXPORT int     gsl_sf_lambert_W0_e(double x, gsl_sf_result * result);
  GSL_EXPORT double  gsl_sf_lambert_W0(double x);
  
  
  /* Lambert's Function W_{-1}(x)
   *
   * W_{-1}(x) is the second real branch of the
   * implicit function defined by W e^W = x.
   * It agrees with W_0(x) when x >= 0.
   *
   * -1/E < x < \infty
   *
   * exceptions: GSL_MAXITER;
   */
  GSL_EXPORT int     gsl_sf_lambert_Wm1_e(double x, gsl_sf_result * result);
  GSL_EXPORT double  gsl_sf_lambert_Wm1(double x);
  
  
  __END_DECLS
  
  #endif /* __GSL_SF_LAMBERT_H__ */
  