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Groups > comp.lang.c > #167149
| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: How to optimize this search? |
| Date | 2022-08-23 16:58 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <87a67vuf2n.fsf@bsb.me.uk> (permalink) |
| References | (2 earlier) <5_NMK.799766$ntj.539650@fx15.iad> <ac7f8956-aadb-4179-9327-ab8a25547de9n@googlegroups.com> <20220823145856.464a208687d544911b246825@g{oogle}mail.com> <607d6a50-9932-4b63-9108-0894646ad04bn@googlegroups.com> <20220823175014.5b34c47ce60ab0dd18768269@g{oogle}mail.com> |
Anton Shepelev <anton.txt@g{oogle}mail.com> writes:
> Thiago Adams to Anton Shepelev:
>
>> > If speed is that important, which does not seem so to me
>> > in your case, generate a perfect hash.
>>
>> The perfect hash will ensure each keyword has a unique
>> hash right?
>
> Yes.
>
>> So we need hash the input then we have the index in a
>> table. Then because the input can have by coincidence the
>> same hash we need strcmp.
>
> I am confused. A perfect hash is designed to avoid
> collisions. Why shluld we need strcmp?
There are no collision among the keywords, but some strings that are not
keywords might hash the same value as one.
I suppose there might be a way to generate a truly perfect hash that
generates an index outside the table for every possible string not in
it, but I've not seen such a thing.
>> The total time is time to compute
>> hash + (index table is fast) + strcmp.
>> I believe we can have better performance than this for
>> some cases.
You mean with an FSA? It would be interesting to compare times. Also
implementation times. I was cooking dinner when I suggested a perfect
hash, but I had a program running withing 45 minutes of posting. That
included finding gpref, installing it reading enough documentation to
get to going.
> But the hasing ought to be done at compile time or at
> program startup.
Not sure what you mean. You can't hash the input until there is input,
but gperf does, of course, make a static, compile time, hash table.
--
Ben.
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How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 07:17 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 07:34 -0700
Re: How to optimize this search? scott@slp53.sl.home (Scott Lurndal) - 2022-08-22 16:17 +0000
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:24 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:38 -0700
Re: How to optimize this search? scott@slp53.sl.home (Scott Lurndal) - 2022-08-22 17:03 +0000
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-23 14:58 +0300
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 05:02 -0700
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-23 17:50 +0300
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-23 16:58 +0100
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-23 19:21 +0300
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 09:46 -0700
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-23 20:06 +0300
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-23 23:39 +0100
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-24 11:20 +0300
Re: How to optimize this search? Anton Shepelev <anton.txt@gmail.com> - 2022-08-25 00:52 +0300
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 23:23 +0100
Re: How to optimize this search? Anton Shepelev <anton.txt@gmail.com> - 2022-08-26 01:38 +0300
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-26 00:55 +0100
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-26 12:02 +0300
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-26 04:10 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 10:47 -0700
Re: How to optimize this search? scott@slp53.sl.home (Scott Lurndal) - 2022-08-22 18:10 +0000
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 15:22 -0700
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-22 15:37 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 16:28 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-23 01:18 +0100
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 18:01 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-23 00:07 +0000
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 18:12 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-23 01:54 +0000
Re: How to optimize this search? David Brown <david.brown@hesbynett.no> - 2022-08-23 08:50 +0200
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 04:18 -0700
Re: How to optimize this search? David Brown <david.brown@hesbynett.no> - 2022-08-23 15:50 +0200
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-22 18:51 +0000
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 16:34 +0100
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:14 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 17:33 +0100
Re: How to optimize this search? Siri Cruise <chine.bleu@yahoo.com> - 2022-08-22 08:44 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 16:53 +0100
Re: How to optimize this search? Siri Cruise <chine.bleu@yahoo.com> - 2022-08-22 09:29 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 17:36 +0100
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 16:53 +0100
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:11 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-22 19:30 +0000
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 14:19 -0700
Re: How to optimize this search? Öö Tiib <ootiib@hot.ee> - 2022-08-22 14:36 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-22 22:49 +0000
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 05:13 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 15:55 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 16:36 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 17:42 -0700
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-23 18:36 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-24 03:34 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 04:40 -0700
Re: How to optimize this search? David Brown <david.brown@hesbynett.no> - 2022-08-24 09:30 +0200
Re: How to optimize this search? William Ahern <william@25thandClement.com> - 2022-08-24 12:36 -0700
Re: How to optimize this search? Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-22 17:51 +0200
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-22 16:55 +0100
Re: How to optimize this search? Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-22 18:14 +0200
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:15 -0700
Re: How to optimize this search? Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-22 18:28 +0200
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:34 -0700
Re: How to optimize this search? Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-22 18:35 +0200
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 09:45 -0700
Re: How to optimize this search? Bonita Montero <Bonita.Montero@gmail.com> - 2022-08-22 18:51 +0200
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-23 17:53 +0300
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 10:20 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-22 10:53 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-22 23:31 +0000
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-22 17:04 -0700
Re: How to optimize this search? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-08-23 09:50 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 10:07 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 11:28 -0700
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-23 12:17 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 13:16 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 13:18 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-23 13:23 -0700
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-23 13:40 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 16:26 -0700
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-23 16:50 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-23 17:26 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-23 23:54 +0000
Re: How to optimize this search? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-08-23 17:16 -0700
Re: How to optimize this search? David Brown <david.brown@hesbynett.no> - 2022-08-24 09:43 +0200
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-24 04:03 -0700
Re: How to optimize this search? antispam@math.uni.wroc.pl - 2022-08-24 14:15 +0000
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 13:28 +0100
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 06:25 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 06:50 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 15:19 +0100
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 09:46 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 20:40 +0100
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 10:08 -0700
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 20:42 +0100
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-24 07:31 -0700
Re: How to optimize this search? Anton Shepelev <anton.txt@gmail.com> - 2022-08-25 01:04 +0300
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 16:43 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 16:54 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-24 17:08 -0700
Re: How to optimize this search? Anton Shepelev <anton.txt@gmail.com> - 2022-08-26 01:47 +0300
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-26 05:40 -0700
Re: How to optimize this search? Thiago Adams <thiago.adams@gmail.com> - 2022-08-26 06:29 -0700
Re: How to optimize this search? scott@slp53.sl.home (Scott Lurndal) - 2022-08-26 14:05 +0000
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-24 06:45 -0700
Re: How to optimize this search? bart c <bart4858@gmail.com> - 2022-08-24 13:01 -0700
Re: How to optimize this search? Anton Shepelev <anton.txt@gmail.com> - 2022-08-25 01:17 +0300
Re: How to optimize this search? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-08-24 23:38 +0100
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-25 11:29 +0300
Re: How to optimize this search? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-08-25 11:33 +0300
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