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| author | Joseph Myers <joseph@codesourcery.com> | 2013-04-24 18:49:13 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2013-04-24 18:49:13 +0000 |
| commit | 2f38fbfe09e4856c571bf0c80844e5dac9bc77ec (patch) | |
| tree | 6fc88a0757c95d123f8e8cd9b14e973c9a654d88 /math/s_catanh.c | |
| parent | 45d69176e8b6dc0787dcb8e52e4283b8e7e5e282 (diff) | |
| download | glibc-2f38fbfe09e4856c571bf0c80844e5dac9bc77ec.tar.gz glibc-2f38fbfe09e4856c571bf0c80844e5dac9bc77ec.tar.xz glibc-2f38fbfe09e4856c571bf0c80844e5dac9bc77ec.zip | |
Fix catan, catanh inaccuracy through use of log (bug 15394).
Diffstat (limited to 'math/s_catanh.c')
| -rw-r--r-- | math/s_catanh.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/math/s_catanh.c b/math/s_catanh.c index 5371f44b67..0ee8c64b6f 100644 --- a/math/s_catanh.c +++ b/math/s_catanh.c @@ -64,7 +64,14 @@ __catanh (__complex__ double x) double den = 1.0 - __real__ x; den = i2 + den * den; - __real__ res = 0.25 * (__ieee754_log (num) - __ieee754_log (den)); + double f = num / den; + if (f < 0.5) + __real__ res = 0.25 * __ieee754_log (f); + else + { + num = 4.0 * __real__ x; + __real__ res = 0.25 * __log1p (num / den); + } den = 1 - __real__ x * __real__ x - i2; |