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| author | Joseph Myers <joseph@codesourcery.com> | 2013-05-01 10:07:00 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2013-05-01 10:07:00 +0000 |
| commit | 10de07f5fdd9eaf3a808d4461401f5b661095614 (patch) | |
| tree | 844a1ed48df767e65d46a429f0e1b062e0e2fad5 /math/s_catanl.c | |
| parent | cb4d54147e620f4267d1c675bf2daec0a8e7c809 (diff) | |
| download | glibc-10de07f5fdd9eaf3a808d4461401f5b661095614.tar.gz glibc-10de07f5fdd9eaf3a808d4461401f5b661095614.tar.xz glibc-10de07f5fdd9eaf3a808d4461401f5b661095614.zip | |
Fix catan, catanh spurious underflows (bug 15423).
Diffstat (limited to 'math/s_catanl.c')
| -rw-r--r-- | math/s_catanl.c | 42 |
1 files changed, 26 insertions, 16 deletions
diff --git a/math/s_catanl.c b/math/s_catanl.c index 1a815ad776..9bb5e012e6 100644 --- a/math/s_catanl.c +++ b/math/s_catanl.c @@ -85,7 +85,7 @@ __catanl (__complex__ long double x) } else { - long double r2, num, den, f, absx, absy; + long double den, absx, absy; absx = fabsl (__real__ x); absy = fabsl (__imag__ x); @@ -96,10 +96,10 @@ __catanl (__complex__ long double x) absy = t; } - if (absx >= 1.0L) - den = (1.0L - absx) * (1.0L + absx) - absy * absy; - else if (absx >= 0.75L && absy < LDBL_EPSILON / 2.0L) + if (absy < LDBL_EPSILON / 2.0L) den = (1.0L - absx) * (1.0L + absx); + else if (absx >= 1.0L) + den = (1.0L - absx) * (1.0L + absx) - absy * absy; else if (absx >= 0.75L || absy >= 0.5L) den = -__x2y2m1l (absx, absy); else @@ -107,21 +107,31 @@ __catanl (__complex__ long double x) __real__ res = 0.5L * __ieee754_atan2l (2.0L * __real__ x, den); - r2 = __real__ x * __real__ x; + if (fabsl (__imag__ x) == 1.0L + && fabsl (__real__ x) < LDBL_EPSILON * LDBL_EPSILON) + __imag__ res = (__copysignl (0.5L, __imag__ x) + * (M_LN2l - __ieee754_logl (fabsl (__real__ x)))); + else + { + long double r2 = 0.0L, num, f; - num = __imag__ x + 1.0L; - num = r2 + num * num; + if (fabsl (__real__ x) >= LDBL_EPSILON * LDBL_EPSILON) + r2 = __real__ x * __real__ x; - den = __imag__ x - 1.0L; - den = r2 + den * den; + num = __imag__ x + 1.0L; + num = r2 + num * num; - f = num / den; - if (f < 0.5L) - __imag__ res = 0.25L * __ieee754_logl (f); - else - { - num = 4.0L * __imag__ x; - __imag__ res = 0.25L * __log1pl (num / den); + den = __imag__ x - 1.0L; + den = r2 + den * den; + + f = num / den; + if (f < 0.5L) + __imag__ res = 0.25L * __ieee754_logl (f); + else + { + num = 4.0L * __imag__ x; + __imag__ res = 0.25L * __log1pl (num / den); + } } } |