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Fix cacosh inaccuracy and spurious exceptions (bug 15327).

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This commit is contained in:
Joseph Myers
2013-04-02 22:54:00 +00:00
parent e7906a4789
commit 52ce486045
8 changed files with 2300 additions and 130 deletions
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33
math/s_cacoshf.c
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@ -64,32 +64,25 @@ __cacoshf (__complex__ float x)
__real__ res = 0.0;
__imag__ res = __copysignf (M_PI_2, __imag__ x);
}
/* The factor 16 is just a guess. */
else if (16.0 * fabsf (__imag__ x) < fabsf (__real__ x))
{
/* Kahan's formula which avoid cancellation through subtraction in
some cases. */
res = 2.0 * __clogf (__csqrtf ((x + 1.0) / 2.0)
+ __csqrtf ((x - 1.0) / 2.0));
if (signbit (__real__ res))
__real__ res = 0.0f;
}
else
{
__complex__ float y;
__real__ y = (__real__ x - __imag__ x) * (__real__ x + __imag__ x) - 1.0;
__imag__ y = 2.0 * __real__ x * __imag__ x;
__real__ y = -__imag__ x;
__imag__ y = __real__ x;
y = __csqrtf (y);
y = __kernel_casinhf (y, 1);
if (signbit (__real__ x))
y = -y;
__real__ y += __real__ x;
__imag__ y += __imag__ x;
res = __clogf (y);
if (signbit (__imag__ x))
{
__real__ res = __real__ y;
__imag__ res = -__imag__ y;
}
else
{
__real__ res = -__real__ y;
__imag__ res = __imag__ y;
}
}
return res;