Date: Tue, 28 May 2013 20:21:16 -0500 From: Stephen Montgomery-Smith <stephen@missouri.edu> To: freebsd-numerics@freebsd.org Subject: Re: Patches for s_expl.c Message-ID: <51A5580C.9000607@missouri.edu> In-Reply-To: <20130529000622.GA53899@troutmask.apl.washington.edu> References: <20130528172242.GA51485@troutmask.apl.washington.edu> <20130529062437.V4648@besplex.bde.org> <20130528225310.GA53144@troutmask.apl.washington.edu> <51A53B1A.9040607@missouri.edu> <20130529000622.GA53899@troutmask.apl.washington.edu>
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On 05/28/2013 07:06 PM, Steve Kargl wrote: > On Tue, May 28, 2013 at 06:17:46PM -0500, Stephen Montgomery-Smith wrote: >> On 05/28/2013 05:53 PM, Steve Kargl wrote: >> >>> Given that I've merged, unmerged, remerged, disremerged, and >>> undisremerged numerous diffs over the last 2+ years, I am not >>> surprise that there are issues with the patches. I'm neither >>> an expert in floating arithmetic nor style(9). If I understand >>> half of what you write when you annotate one of your diffs, I >>> feel lucky. >>> >>> (Un)fortunately, I only have a few hours this week to work on >>> expl/expm1l, and then I'll disappear again for a month or two >>> (due to work and life). (Un)fortunately, theraven (under the >>> pretense of core) has threaten to completely rendered libm into >>> a crippled useless mess by mapping all unimplemented long double >>> functions to their double cousins. When/if it comes to pass >>> that I have to untangle whatever theraven does, I'll likely >>> just walk away from libm hacking. >> >> I think it is better to commit "as is" if you cannot make all the changes. >> >> As for me, I don't really understand the need to be so consistent with >> style, nor to get every last drop of optimization. In particular, >> regarding style, I think it is like people talking different languages. >> You could insist that everyone speak a common language, but it is far >> better for the intellectual commons if people learn other peoples' >> languages. >> >> Anyway, I think it is better for Steve to commit, and then for Bruce to >> make changes later on. >> > > It's too late. In making some change since the last time I test > has introduced a massive regression in the computation of expm1l. > > laptop-kargl:kargl[204] ./testl -n 5 -b > prec: 64 > For x in [-64.0000:-0.1659], 5M expm1l calls in 2.176513 seconds. > For x in [-0.1659:0.1659], 5M expm1l calls in 0.415051 seconds. > For x in [0.1659:11356.0000], 5M expm1l calls in 0.550342 seconds. > > Notice, the first interval is now 4 to 5 times slower than the > other intervals. This was not the case with an older version > of the code. > > :( I think it is still better to commit. Then figure out where the regression was later, when you have time.
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