Re: Good hash for pointers

From	Michael S <already5chosen@yahoo.com>
Newsgroups	comp.lang.c
Subject	Re: Good hash for pointers
Date	2024-06-05 12:34 +0300
Organization	A noiseless patient Spider
Message-ID	<20240605123450.00003fdb@yahoo.com> (permalink)
References	(8 earlier) <86le3wfsmd.fsf@linuxsc.com> <v2voe7$3fr50$1@raubtier-asyl.eternal-september.org> <86ed9ofq14.fsf@linuxsc.com> <20240605005916.00001b33@yahoo.com> <v3pa1v$tf0g$1@raubtier-asyl.eternal-september.org>

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On Wed, 5 Jun 2024 11:10:24 +0200
Bonita Montero <Bonita.Montero@gmail.com> wrote:

> Am 04.06.2024 um 23:59 schrieb Michael S:
> 
> > 18446744073709551557 is indeed very bad (too close to 2**64).  
> 
> It doesn't matter how close the prime is to 2 ^ 64 since the
> results are chopped.
> 
> 

I have no idea what you are talking about. 
18446744073709551557 == -59.
That's a very small number. With factor like that, for typical case of
pointers that are <= 2**40 and
for table size in 1000s or 10,000s, all keys (==pointers) would be
pushed into the same (uppermost) slot of the table with no hashing at
all.
You can run my test bench and see it yourself.

On the other hand, prime in range (2**63..2**64) that does not have too
many bits set or cleared works very well. But majority of non-primes
with the same properties would work very well as well.

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Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 18:04 +0200
  Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-26 09:24 -0700
    Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 18:36 +0200
      Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-26 10:20 -0700
        Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 19:39 +0200
          Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-26 19:54 +0200
          Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-27 08:07 +0200
            Re: Good hash for pointers Ben Bacarisse <ben@bsb.me.uk> - 2024-05-28 11:07 +0100
              Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-30 10:10 +0200
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-05-30 11:27 +0200
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-30 19:26 -0700
          Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-30 19:27 -0700
            Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-02 10:45 +0300
              Re: Good hash for pointers "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-02 12:42 -0700
                Re: Good hash for pointers "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-03 12:35 -0700
              Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-02 16:02 -0700
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-03 10:50 +0300
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-03 18:02 -0700
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-04 11:38 +0300
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-04 22:10 -0700
              Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-03 16:34 +0200
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-03 17:46 +0300
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-03 17:54 +0200
                Re: Good hash for pointers bart <bc@freeuk.com> - 2024-06-03 17:24 +0100
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-03 20:16 +0300
                Re: Good hash for pointers bart <bc@freeuk.com> - 2024-06-03 19:48 +0100
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-03 22:41 +0300
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-03 22:51 +0300
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-03 16:51 -0700
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-03 17:01 -0700
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-03 20:25 +0200
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-03 19:50 +0300
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-03 20:31 +0200
        Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-05 00:59 +0300
          Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-05 11:10 +0200
            Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-05 12:34 +0300
              Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-05 12:05 +0200
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-05 13:11 +0300
          Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-05 08:58 -0700
            AES problem (was: Good hash for pointers) Michael S <already5chosen@yahoo.com> - 2024-06-05 19:51 +0300
              Re: AES problem (was: Good hash for pointers) Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-05 21:24 -0700
            Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-05 19:59 +0300
              Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-05 21:40 -0700
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-06 11:00 +0300
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-17 00:56 -0700
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-17 12:39 +0300
            Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-06 13:35 +0300
              Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-16 04:38 -0700
                Re: Good hash for pointers "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-16 12:34 -0700
          Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-07 20:53 +0200
            Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-09 13:35 +0200
              Re: Good hash for pointers Richard Harnden <richard.nospam@gmail.invalid> - 2024-06-09 12:40 +0100
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-09 15:09 +0200
              Re: Good hash for pointers Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-10 01:34 +0100
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-09 18:31 -0700
                Re: Good hash for pointers Michael S <already5chosen@yahoo.com> - 2024-06-10 15:14 +0300
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-10 14:40 +0200
                Re: Good hash for pointers Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-15 20:32 -0700
                Re: Good hash for pointers Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-10 09:35 +0200

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