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glibc  2.9
Functions
s_cacoshf.c File Reference
#include <complex.h>
#include <math.h>
#include "math_private.h"
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Functions

__complex__ float __cacoshf (__complex__ float x)

Function Documentation

__complex__ float __cacoshf ( __complex__ float  x)

Definition at line 27 of file s_cacoshf.c.

{
  __complex__ float res;
  int rcls = fpclassify (__real__ x);
  int icls = fpclassify (__imag__ x);

  if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
    {
      if (icls == FP_INFINITE)
       {
         __real__ res = HUGE_VALF;

         if (rcls == FP_NAN)
           __imag__ res = __nanf ("");
         else
           __imag__ res = __copysignf ((rcls == FP_INFINITE
                                    ? (__real__ x < 0.0
                                       ? M_PI - M_PI_4 : M_PI_4)
                                    : M_PI_2), __imag__ x);
       }
      else if (rcls == FP_INFINITE)
       {
         __real__ res = HUGE_VALF;

         if (icls >= FP_ZERO)
           __imag__ res = __copysignf (signbit (__real__ x) ? M_PI : 0.0,
                                   __imag__ x);
         else
           __imag__ res = __nanf ("");
       }
      else
       {
         __real__ res = __nanf ("");
         __imag__ res = __nanf ("");
       }
    }
  else if (rcls == FP_ZERO && icls == FP_ZERO)
    {
      __real__ res = 0.0;
      __imag__ res = __copysignf (M_PI_2, __imag__ x);
    }
  else
    {
#if 1
      __complex__ float y;

      __real__ y = (__real__ x - __imag__ x) * (__real__ x + __imag__ x) - 1.0;
      __imag__ y = 2.0 * __real__ x * __imag__ x;

      y = __csqrtf (y);

      if (__real__ x < 0.0)
       y = -y;

      __real__ y += __real__ x;
      __imag__ y += __imag__ x;

      res = __clogf (y);
#else
      float re2 = __real__ x * __real__ x;
      float im2 = __imag__ x * __imag__ x;
      float sq = re2 - im2 - 1.0;
      float ro = __ieee754_sqrtf (sq * sq + 4 * re2 * im2);
      float a = __ieee754_sqrtf ((sq + ro) / 2.0);
      float b = __ieee754_sqrtf ((-sq + ro) / 2.0);

      __real__ res = 0.5 * __ieee754_logf (re2 + __real__ x * 2 * a
                                      + im2 + __imag__ x * 2 * b
                                      + ro);
      __imag__ res = __ieee754_atan2f (__imag__ x + b, __real__ x + a);
#endif

      /* We have to use the positive branch.  */
      if (__real__ res < 0.0)
       res = -res;
    }

  return res;
}

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