Date: Thu, 22 Aug 2024 22:23:07 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 281001] Improve accuracy of asinf(x) Message-ID: <bug-281001-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=281001 Bug ID: 281001 Summary: Improve accuracy of asinf(x) Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: bin Assignee: bugs@FreeBSD.org Reporter: kargl@FreeBSD.org Created attachment 253025 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=253025&action=edit patch to lib/msun/src/e_asinf.c The attached patch improves the accuracy of asinf(x). It contains a better rational approximation. For exhaustive testing in the interval, the current libm gives % ./tlibm asin -fPED -x 0x1p-12f -X 1 Interval tested for asinf: [0.000244141,1] ulp <= 0.5: 97.916% 98564994 | 97.916% 98564994 0.5 < ulp < 0.6: 2.038% 2051023 | 99.953% 100616017 0.6 < ulp < 0.7: 0.047% 47254 | 100.000% 100663271 0.7 < ulp < 0.8: 0.000% 25 | 100.000% 100663296 Max ulp: 0.729891 at 5.00732839e-01 which isn't too bad given that much of the computation is actually done in double floating point. With the new rational approximation, exhaustive testing yields % ./tlibm asin -fPED -x 0x1p-12f -X 1 Interval tested for asinf: [0.000244141,1] ulp <= 0.5: 99.711% 100372643 | 99.711% 100372643 0.5 < ulp < 0.6: 0.288% 290357 | 100.000% 100663000 0.6 < ulp < 0.7: 0.000% 296 | 100.000% 100663296 Max ulp: 0.636344 at 5.09706438e-01 That is, it's better. -- You are receiving this mail because: You are the assignee for the bug.home | help
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