Date: Sun, 8 Dec 2013 10:59:41 -0800 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Bruce Evans <brde@optusnet.com.au> Cc: freebsd-numerics@FreeBSD.org, Filipe Maia <filipe.c.maia@gmail.com> Subject: Re: dead code in lgamma_r[f]? Message-ID: <20131208185941.GA83484@troutmask.apl.washington.edu> In-Reply-To: <20131208183339.GA83010@troutmask.apl.washington.edu> References: <20131205173700.GA64575@troutmask.apl.washington.edu> <20131205182324.GA65135@troutmask.apl.washington.edu> <CAN5hRiV6N1arc4RDv=9JbRiXp-J9o3WzAbeZSOpAxks2ZeG%2B_w@mail.gmail.com> <20131205195225.GA65732@troutmask.apl.washington.edu> <20131206102724.W1033@besplex.bde.org> <20131206114426.I1329@besplex.bde.org> <20131207064602.GA76042@troutmask.apl.washington.edu> <20131208012939.GA80145@troutmask.apl.washington.edu> <20131208141627.F1181@besplex.bde.org> <20131208183339.GA83010@troutmask.apl.washington.edu>
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On Sun, Dec 08, 2013 at 10:33:39AM -0800, Steve Kargl wrote: > > fdlibm's lgammaf_r does not appear to have an issue near 1 or 2. > Starting at the lower bound of each interval and using nextafterf > to scan up to the upper bound, I'm seeing > > % make testf && ./testf > Interval: Time ULP Value > [4.7683716e-07, 2.0000000e+00): 0.04590 0.98491 1.231645e+00 > [2.0000000e+00, 8.0000000e+00): 0.08754 0.82825 4.012439e+00 > [8.0000000e+00, 2.8823038e+17): 0.05841 1.43789 8.942273e+06 > [2.8823038e+17, 2.6584560e+36): 0.05095 0.50000 1.491249e+23 > > where the reference value is from lgamma_r. The different > intervals test specific branches in lgammaf_r. The upper > bound of 2.6584560e36 is 0x1p121. Time is the average value > for all calls in the interval in usec/call. Correction. The timing is for 1 million calls uniformly distributed over the interval. -- Steve
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