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| author | Joseph Myers <joseph@codesourcery.com> | 2013-03-27 14:38:44 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2013-03-27 14:38:44 +0000 |
| commit | 3a7182a14becbf3149419bdbaff4388b636c9f31 (patch) | |
| tree | 16616a6c0915ec7099fcd318204f8e5741571b29 /math/k_casinhl.c | |
| parent | 28831a9a671b109e49d0a4ddce00a08d734bfc97 (diff) | |
| download | glibc-3a7182a14becbf3149419bdbaff4388b636c9f31.tar.gz glibc-3a7182a14becbf3149419bdbaff4388b636c9f31.tar.xz glibc-3a7182a14becbf3149419bdbaff4388b636c9f31.zip | |
Fix casinh inaccuracy near i, imaginary part > 1 (bug 15307).
Diffstat (limited to 'math/k_casinhl.c')
| -rw-r--r-- | math/k_casinhl.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/math/k_casinhl.c b/math/k_casinhl.c index eb090ec3ce..8e5bbd4385 100644 --- a/math/k_casinhl.c +++ b/math/k_casinhl.c @@ -84,6 +84,39 @@ __kernel_casinhl (__complex__ long double x, int adj) else __imag__ res = __ieee754_atan2l (s, rx); } + else if (ix > 1.0L && ix < 1.5L && rx < 0.5L) + { + if (rx < LDBL_EPSILON * LDBL_EPSILON) + { + long double ix2m1 = (ix + 1.0L) * (ix - 1.0L); + long double s = __ieee754_sqrtl (ix2m1); + + __real__ res = __log1pl (2.0L * (ix2m1 + ix * s)) / 2.0L; + if (adj) + __imag__ res = __ieee754_atan2l (rx, __copysignl (s, __imag__ x)); + else + __imag__ res = __ieee754_atan2l (s, rx); + } + else + { + long double ix2m1 = (ix + 1.0L) * (ix - 1.0L); + long double rx2 = rx * rx; + long double f = rx2 * (2.0L + rx2 + 2.0L * ix * ix); + long double d = __ieee754_sqrtl (ix2m1 * ix2m1 + f); + long double dp = d + ix2m1; + long double dm = f / dp; + long double r1 = __ieee754_sqrtl ((dm + rx2) / 2.0L); + long double r2 = rx * ix / r1; + + __real__ res + = __log1pl (rx2 + dp + 2.0L * (rx * r1 + ix * r2)) / 2.0L; + if (adj) + __imag__ res = __ieee754_atan2l (rx + r1, __copysignl (ix + r2, + __imag__ x)); + else + __imag__ res = __ieee754_atan2l (ix + r2, rx + r1); + } + } else if (ix == 1.0L && rx < 0.5L) { if (rx < LDBL_EPSILON / 8.0L) |