Date: Fri, 23 Aug 2024 18:06:58 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 281001] Improve accuracy of asinf(x) Message-ID: <bug-281001-227-kpUWXh0O0o@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-281001-227@https.bugs.freebsd.org/bugzilla/> References: <bug-281001-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D281001 Steve Kargl <kargl@FreeBSD.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Attachment #253025|0 |1 is obsolete| | --- Comment #2 from Steve Kargl <kargl@FreeBSD.org> --- Created attachment 253043 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D253043&action= =3Dedit new patch with changes for both asinf() and acosf(). The new patch has updated the rational approximation in acosf() to match the new rational approximation in asinf(). This change provides only a small improve in accuracy in exhaustive testing over the relevant intervals. Unpatched acosf() gives % ./tlibm acos -fPED -x -1 -X -0x1p-12f Interval tested for acosf: [-1,-0.000244141] ulp <=3D 0.5: 97.008% 97651921 | 97.008% 97651921 0.5 < ulp < 0.6: 2.441% 2457242 | 99.450% 100109163 0.6 < ulp < 0.7: 0.472% 475503 | 99.922% 100584666 0.7 < ulp < 0.8: 0.071% 71309 | 99.993% 100655975 0.8 < ulp < 0.9: 0.007% 7319 | 100.000% 100663294 0.9 < ulp < 1.0: 0.000% 2 | 100.000% 100663296 Max ulp: 0.914007 at -5.01484931e-01 % ./tlibm acos -fPED -x 0x1p-12f -X 1 Interval tested for acosf: [0.000244141,1] ulp <=3D 0.5: 97.317% 97962530 | 97.317% 97962530 0.5 < ulp < 0.6: 2.340% 2355182 | 99.657% 100317712 0.6 < ulp < 0.7: 0.314% 316134 | 99.971% 100633846 0.7 < ulp < 0.8: 0.029% 29450 | 100.000% 100663296 Max ulp: 0.796035 at 4.99814630e-01 Patched acosf() gives % ./tlibm acos -fPED -x -1 -X -0x1p-12f Interval tested for acosf: [-1,-0.000244141] ulp <=3D 0.5: 97.010% 97653245 | 97.010% 97653245 0.5 < ulp < 0.6: 2.442% 2458373 | 99.452% 100111618 0.6 < ulp < 0.7: 0.473% 476012 | 99.925% 100587630 0.7 < ulp < 0.8: 0.068% 68603 | 99.993% 100656233 0.8 < ulp < 0.9: 0.007% 7063 | 100.000% 100663296 Max ulp: 0.896189 at -5.04511118e-01 % ./tlibm acos -fPED -x 0x1p-12f -X 1 Interval tested for acosf: [0.000244141,1] ulp <=3D 0.5: 97.650% 98298175 | 97.650% 98298175 0.5 < ulp < 0.6: 2.028% 2041709 | 99.679% 100339884 0.6 < ulp < 0.7: 0.292% 293555 | 99.970% 100633439 0.7 < ulp < 0.8: 0.030% 29857 | 100.000% 100663296 Max ulp: 0.775875 at 4.91849005e-01 --=20 You are receiving this mail because: You are the assignee for the bug.=
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