From: "John B. Matthews" <nospam@nospam.invalid>
Subject: Re: Hash Type Size
Date: Tue, 03 Sep 2013 17:21:21 -0400
Date: 2013-09-03T17:21:21-04:00 [thread overview]
Message-ID: <nospam-717EC9.17212103092013@news.aioe.org> (raw)
In-Reply-To: c6c24f9a-c5ba-4068-be58-c7d1cff4889b@googlegroups.com
In article <c6c24f9a-c5ba-4068-be58-c7d1cff4889b@googlegroups.com>,
Peter Brooks <peter.h.m.brooks@gmail.com> wrote:
> On Tuesday, 3 September 2013 12:50:04 UTC+2, John B. Matthews wrote:
> >
> > As a concrete example, this program [1] tallies collisions
> > using an instance of Ada.Strings.Bounded.Hash on words found
> > in a dictionary. While it's specific to GNAT, it may suggest
> > how to obtain a baseline against which to compare your
> > implementation(s).
> >
> > [1] <http://home.roadrunner.com/~jbmatthews/jumble.html#sec2>
> >
> Thank you for that -it's extremely useful. 32% collisions is far
> too high for me, so I certainly need a better hash function.
You are welcome. That 2009 data was obtained using GNAT 4.3.4;
newer versions are typically better. For example, the GNAT 4.6
implementation yields the following result:
./collisions
0: 305643 (77.72%)
1: 76947 (19.57%)
2: 9790 (2.49%)
3: 805 (0.20%)
4: 56 (0.01%)
5: 1 (0.00%)
--
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>
next prev parent reply other threads:[~2013-09-03 21:21 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-18 21:05 Hash Type Size sbelmont700
2013-08-19 1:03 ` AdaMagica
2013-08-19 22:21 ` Randy Brukardt
2013-08-19 22:29 ` Randy Brukardt
2013-08-19 22:12 ` Randy Brukardt
2013-08-31 6:22 ` Peter Brooks
2013-08-31 15:57 ` sbelmont700
2013-09-03 1:47 ` Randy Brukardt
2013-09-03 2:31 ` Peter Brooks
2013-09-03 10:50 ` John B. Matthews
2013-09-03 17:18 ` Peter Brooks
2013-09-03 21:21 ` John B. Matthews [this message]
2013-09-04 4:50 ` Paul Rubin
2013-09-04 4:54 ` Paul Rubin
2013-09-05 19:30 ` John B. Matthews
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