libgfortran/generated/exp_c4.c

   1 /* Complex exponential functions
   2    Copyright 2002, 2004 Free Software Foundation, Inc.
   3    Contributed by Paul Brook <paul@nowt.org>
   4
   5 This file is part of the GNU Fortran 95 runtime library (libgfor).
   6
   7 Libgfortran is free software; you can redistribute it and/or
   8 modify it under the terms of the GNU Lesser General Public
   9 License as published by the Free Software Foundation; either
  10 version 2.1 of the License, or (at your option) any later version.
  11
  12 Libgfortran is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU Lesser General Public License for more details.
  16
  17 You should have received a copy of the GNU Lesser General Public
  18 License along with libgfor; see the file COPYING.LIB.  If not,
  19 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21 #include <math.h>
  22 #include "libgfortran.h"
  23
  24
  25 /* z = a + ib  */
  26 /* Absolute value.  */
  27 GFC_REAL_4
  28 cabsf (GFC_COMPLEX_4 z)
  29 {
  30   return hypotf (REALPART (z), IMAGPART (z));
  31 }
  32
  33 /* Complex argument.  The angle made with the +ve real axis.
  34    Range -pi-pi.  */
  35 GFC_REAL_4
  36 cargf (GFC_COMPLEX_4 z)
  37 {
  38   GFC_REAL_4 arg;
  39
  40   return atan2f (IMAGPART (z), REALPART (z));
  41 }
  42
  43 /* exp(z) = exp(a)*(cos(b) + isin(b))  */
  44 GFC_COMPLEX_4
  45 cexpf (GFC_COMPLEX_4 z)
  46 {
  47   GFC_REAL_4 a;
  48   GFC_REAL_4 b;
  49   GFC_COMPLEX_4 v;
  50
  51   a = REALPART (z);
  52   b = IMAGPART (z);
  53   COMPLEX_ASSIGN (v, cosf (b), sinf (b));
  54   return expf (a) * v;
  55 }
  56
  57 /* log(z) = log (cabs(z)) + i*carg(z)  */
  58 GFC_COMPLEX_4
  59 clogf (GFC_COMPLEX_4 z)
  60 {
  61   GFC_COMPLEX_4 v;
  62
  63   COMPLEX_ASSIGN (v, logf (cabsf (z)), cargf (z));
  64   return v;
  65 }
  66
  67 /* log10(z) = log10 (cabs(z)) + i*carg(z)  */
  68 GFC_COMPLEX_4
  69 clog10f (GFC_COMPLEX_4 z)
  70 {
  71   GFC_COMPLEX_4 v;
  72
  73   COMPLEX_ASSIGN (v, log10f (cabsf (z)), cargf (z));
  74   return v;
  75 }
  76
  77 /* pow(base, power) = cexp (power * clog (base))  */
  78 GFC_COMPLEX_4
  79 cpowf (GFC_COMPLEX_4 base, GFC_COMPLEX_4 power)
  80 {
  81   return cexpf (power * clogf (base));
  82 }
  83
  84 /* sqrt(z).  Algorithm pulled from glibc.  */
  85 GFC_COMPLEX_4
  86 csqrtf (GFC_COMPLEX_4 z)
  87 {
  88   GFC_REAL_4 re;
  89   GFC_REAL_4 im;
  90   GFC_COMPLEX_4 v;
  91
  92   re = REALPART (z);
  93   im = IMAGPART (z);
  94   if (im == 0.0)
  95     {
  96       if (re < 0.0)
  97         {
  98           COMPLEX_ASSIGN (v, 0.0, copysignf (sqrtf (-re), im));
  99         }
 100       else
 101         {
 102           COMPLEX_ASSIGN (v, fabsf (sqrt (re)),
 103                           copysignf (0.0, im));
 104         }
 105     }
 106   else if (re == 0.0)
 107     {
 108       GFC_REAL_4 r;
 109
 110       r = sqrtf (0.5 * fabs (im));
 111
 112       COMPLEX_ASSIGN (v, copysignf (r, im), r);
 113     }
 114   else
 115     {
 116       GFC_REAL_4 d, r, s;
 117
 118       d = hypotf (re, im);
 119       /* Use the identity   2  Re res  Im res = Im x
 120          to avoid cancellation error in  d +/- Re x.  */
 121       if (re > 0)
 122         {
 123           r = sqrtf (0.5 * d + 0.5 * re);
 124           s = (0.5 * im) / r;
 125         }
 126       else
 127         {
 128           s = sqrtf (0.5 * d - 0.5 * re);
 129           r = fabsf ((0.5 * im) / s);
 130         }
 131
 132       COMPLEX_ASSIGN (v, r, copysignf (s, im));
 133     }
 134   return v;
 135 }
 136