File:  [gforth] / gforth / engine / atanh.c
Revision 1.7: download - view: text, annotated - select for diffs
Mon Dec 31 19:02:25 2007 UTC (13 years, 6 months ago) by anton
Branches: MAIN
CVS tags: v0-7-0, HEAD
updated copyright year after changing license notice

    1: /* replacement for asinh, acosh, and atanh */
    2: 
    3: /* 
    4:   Copyright (C) 1996,2000,2003,2007 Free Software Foundation, Inc.
    5: 
    6:   This file is part of Gforth.
    7: 
    8:   Gforth is free software; you can redistribute it and/or
    9:   modify it under the terms of the GNU General Public License
   10:   as published by the Free Software Foundation, either version 3
   11:   of the License, or (at your option) any later version.
   12: 
   13:   This program is distributed in the hope that it will be useful,
   14:   but WITHOUT ANY WARRANTY; without even the implied warranty of
   15:   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   16:   GNU General Public License for more details.
   17: 
   18:   You should have received a copy of the GNU General Public License
   19:   along with this program; if not, see http://www.gnu.org/licenses/.
   20: */
   21: 
   22: #include <math.h>
   23: 
   24: double atanh(double r1)
   25: {
   26:   double r2=r1 < 0 ? -r1 : r1;
   27:   double r3=log((r2/(1.0-r2)*2)+1)/2;
   28: 
   29:   return r1 < 0 ? -r3 : r3;
   30:   /* fdup f0< >r fabs 1. d>f fover f- f/  f2* flnp1 f2/
   31:      r> IF  fnegate  THEN ;
   32:      */
   33: }
   34: 
   35: double asinh(double r1)
   36: {
   37:   return atanh(r1/sqrt(1.0+r1*r1));
   38:   /* fdup fdup f* 1. d>f f+ fsqrt f/ fatanh ; */
   39: }
   40: 
   41: double acosh(double r1)
   42: {
   43:   return(log(r1+sqrt(r1*r1-1.0)));
   44:   /* fdup fdup f* 1. d>f f- fsqrt f+ fln ; */
   45: }

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