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| author | Joseph Myers <joseph@codesourcery.com> | 2013-04-30 11:27:35 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2013-04-30 11:27:35 +0000 |
| commit | caf84319c1614d8aa867d8db80219f4e9b1bf735 (patch) | |
| tree | 08263d4ddcdf643fc258daeb43718821a2e2fbde /math/s_catanhl.c | |
| parent | 6dbe713d85fecc1bee99713d745413106af200b7 (diff) | |
| download | glibc-caf84319c1614d8aa867d8db80219f4e9b1bf735.tar.gz glibc-caf84319c1614d8aa867d8db80219f4e9b1bf735.tar.xz glibc-caf84319c1614d8aa867d8db80219f4e9b1bf735.zip | |
Fix catan, catanh inaccuracy from atan2 denominators near 0 (bug 15416).
Diffstat (limited to 'math/s_catanhl.c')
| -rw-r--r-- | math/s_catanhl.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/math/s_catanhl.c b/math/s_catanhl.c index 64c30b5573..ab75b807e0 100644 --- a/math/s_catanhl.c +++ b/math/s_catanhl.c @@ -97,7 +97,25 @@ __catanhl (__complex__ long double x) __real__ res = 0.25L * __log1pl (num / den); } - den = 1 - __real__ x * __real__ x - i2; + long double absx, absy; + + absx = fabsl (__real__ x); + absy = fabsl (__imag__ x); + if (absx < absy) + { + long double t = absx; + absx = absy; + absy = t; + } + + if (absx >= 1.0L) + den = (1.0L - absx) * (1.0L + absx) - absy * absy; + else if (absx >= 0.75 && absy < LDBL_EPSILON / 2.0L) + den = (1.0L - absx) * (1.0L + absx); + else if (absx >= 0.75L || absy >= 0.5L) + den = -__x2y2m1l (absx, absy); + else + den = (1.0L - absx) * (1.0L + absx) - absy * absy; __imag__ res = 0.5L * __ieee754_atan2l (2.0L * __imag__ x, den); } |