Date: Tue, 28 May 2013 17:06:22 -0700 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Stephen Montgomery-Smith <stephen@missouri.edu> Cc: freebsd-numerics@freebsd.org Subject: Re: Patches for s_expl.c Message-ID: <20130529000622.GA53899@troutmask.apl.washington.edu> In-Reply-To: <51A53B1A.9040607@missouri.edu> References: <20130528172242.GA51485@troutmask.apl.washington.edu> <20130529062437.V4648@besplex.bde.org> <20130528225310.GA53144@troutmask.apl.washington.edu> <51A53B1A.9040607@missouri.edu>
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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. :( -- Steve
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