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| From | Tim Rentsch <tr.17687@z991.linuxsc.com> |
| Newsgroups | comp.lang.c |
| Subject | Re: Challenge for Feeb: dealing with large numbers in C |
| Date | Wed, 23 Oct 2019 07:18:16 -0700 |
| Organization | A noiseless patient Spider |
| Lines | 66 |
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Ben Bacarisse <ben.usenet@bsb.me.uk> writes:
> DFS <nospam@dfs.com> writes:
>
>> On 10/21/2019 8:15 AM, Ben Bacarisse wrote:
>>
>>> DFS <nospam@dfs.com> writes:
>>>
>>>> superincomprehensibleness 2116343913154240100000000000000000000
>>>> antidisestablishmentarianism 10816738360843397000000000000000000000
>>>> microspectrophotometrically 5063607945377863500000000000000000000000
>>>> dichlorodiphenyltrichloroetha 29387878280664888000000000000000000000000
>>>> hydroxydesoxycorticosterone 260918185927817140000000000000000000000000
>>>> hydroxydehydrocorticosterone 354994003426527000000000000000000000000000
>>>> cyclotrimethylenetrinitramine
>>>> {} 1816546187380119700000000000000000000000000
>>>> trinitrophenylmethylnitramine
>>>> {} 286030059853623620000000000000000000000000000
>>>>
>>>>
>>>> It's looking like prime products is not the right hash function for a
>>>> table of only 370K entries.
>>>
>>> I'm not sure you are using the right terminology.
>>
>> wiki says "A hash function is any function that can be used to map
>> data of arbitrary size to fixed-size values."
>
> That's a reasonable stab at a definition.
>
>> I don't see why the hashes have to be of equal size for the generator
>> function to be considered a hash function. Or is that just how the
>> term evolved?
>
> I'd say so, yes. But the key point here is that a good hash function
> will not preserve any useful property of the strings. A good hash
> function give a wildly different result if two different letters are
> swapped.
To me a hash function is any deterministic single-valued function
that produces a fixed-sized, integer-valued output (usually with a
dense output space though not necessarily). The key property,
apart from the fixed-size integer output, is that if the hash
values are different then the input values must be different.
Whatever other properties a hash function might or might not have
depend on the application. A good example is a Zobrist hash
https://en.wikipedia.org/wiki/Zobrist_hashing
which has the property that small changes in the input allow easy
re-computation of the hash value.
Certainly there are applications where we would like wildly
different outputs for two inputs with only a single pair of
swapped letters. As I use the term though (and I believe this is
fairly common but I have made no effort to confirm that), it is
perfectly appropriate to call a function that maps anagrams to the
same[1] output value a hash function. Note further that we can do
both at once - a single hash function with a 128-bit output could
have 64 bits that would match for anagrams, and 64 bits that would
give very different results for words with letters swapped. Which
choice makes sense depends on how the hashing is being used, but
all of them count, I would say, as hash functions.
[1] Either usually the same, or assuming a bounded input space.
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Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-20 18:12 -0400
Re: Challenge for Feeb: dealing with large numbers in C Barry Schwarz <schwarzb@delq.com> - 2019-10-20 18:33 -0700
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-20 23:16 -0400
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-21 13:15 +0100
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-21 14:40 -0400
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-22 00:54 +0100
Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-22 10:05 +0200
Re: Challenge for Feeb: dealing with large numbers in C Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-10-23 07:18 -0700
Re: Challenge for Feeb: dealing with large numbers in C Manfred <noname@invalid.add> - 2019-10-26 20:01 +0200
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-26 17:50 -0400
Re: Challenge for Feeb: dealing with large numbers in C Manfred <noname@add.invalid> - 2019-10-28 16:33 +0100
Re: Challenge for Feeb: dealing with large numbers in C Barry Schwarz <schwarzb@delq.com> - 2019-10-21 07:56 -0700
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-21 16:46 +0100
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-21 14:57 -0400
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-21 20:53 +0100
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-21 16:05 -0400
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-21 21:12 +0100
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-21 20:08 -0400
Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-22 10:27 +0200
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-22 19:45 +0100
Re: Challenge for Feeb: dealing with large numbers in C Eli the Bearded <*@eli.users.panix.com> - 2019-10-22 19:58 +0000
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-23 11:46 -0400
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-23 20:02 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 01:38 +0100
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-23 22:10 -0400
Re: Challenge for Feeb: dealing with large numbers in C Ike Naar <ike@sdf.lonestar.org> - 2019-10-24 07:24 +0000
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-24 09:29 -0400
Re: Challenge for Feeb: dealing with large numbers in C James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-10-24 08:45 -0700
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-24 11:56 -0400
Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-24 09:13 -0700
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 18:28 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 10:36 +0100
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-24 09:26 -0400
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 18:29 +0100
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-24 14:38 -0400
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 21:30 +0100
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-24 11:30 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 20:36 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 21:34 +0100
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-24 22:42 +0100
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-24 18:59 -0400
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-25 02:48 +0100
Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-26 04:33 -0700
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-26 17:21 +0100
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-26 18:47 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-26 23:24 +0100
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-27 00:29 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-27 01:58 +0100
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-27 12:02 +0000
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 02:08 +0000
Re: Challenge for Feeb: dealing with large numbers in C Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2019-10-26 14:29 -0600
Re: Challenge for Feeb: dealing with large numbers in C Keith Thompson <kst-u@mib.org> - 2019-10-26 13:36 -0700
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-26 22:06 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-26 23:04 +0100
Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-27 12:49 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-27 18:20 +0000
Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-27 22:45 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 00:08 +0000
Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-27 14:57 -0700
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 01:08 +0000
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-28 01:44 +0000
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 02:31 +0000
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-28 10:42 +0000
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-28 12:45 +0000
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 17:39 +0000
Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-28 20:31 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 20:22 +0000
Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-28 22:07 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 22:22 +0000
Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-29 10:17 +0100
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-29 11:21 +0000
Re: Challenge for Feeb: dealing with large numbers in C already5chosen@yahoo.com - 2019-10-28 11:05 -0700
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-28 19:26 +0000
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 21:08 +0000
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-28 21:57 +0000
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 23:59 +0000
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 00:53 +0000
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-29 01:09 +0000
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 01:32 +0000
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-28 22:44 -0400
Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-29 03:05 -0700
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 11:12 +0000
Re: Challenge for Feeb: dealing with large numbers in C already5chosen@yahoo.com - 2019-10-29 04:19 -0700
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 11:47 +0000
Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-29 05:03 -0700
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 13:16 +0000
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-29 17:13 +0000
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 17:35 +0000
Re: Challenge for Feeb: dealing with large numbers in C Ike Naar <ike@sdf.lonestar.org> - 2019-10-30 07:19 +0000
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-29 16:19 +0000
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 16:50 +0000
Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-29 10:03 -0700
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 17:13 +0000
Re: Challenge for Feeb: dealing with large numbers in C already5chosen@yahoo.com - 2019-10-29 10:23 -0700
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-29 22:20 +0000
Re: Challenge for Feeb: dealing with large numbers in C already5chosen@yahoo.com - 2019-10-30 03:04 -0700
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-30 15:39 +0000
Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-30 09:02 -0700
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-30 19:35 +0000
Re: Challenge for Feeb: dealing with large numbers in C already5chosen@yahoo.com - 2019-10-30 14:11 -0700
Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-31 03:34 +0000
Re: Challenge for Feeb: dealing with large numbers in C Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-04 17:02 -0800
Re: Challenge for Feeb: dealing with large numbers in C Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2019-10-26 12:30 -0400
Re: Challenge for Feeb: dealing with large numbers in C Robert Wessel <robertwessel2@yahoo.com> - 2019-10-26 12:03 -0500
Re: Challenge for Feeb: dealing with large numbers in C Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2019-10-26 14:25 -0600
Re: Challenge for Feeb: dealing with large numbers in C Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-10-24 18:06 -0700
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-21 22:44 +0100
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-21 19:00 -0400
Re: Challenge for Feeb: dealing with large numbers in C Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2019-10-21 10:20 +0800
Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-21 12:44 +0100
Re: Challenge for Feeb: dealing with large numbers in C Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2019-10-21 10:24 +0800
Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-20 23:05 -0400
Re: Challenge for Feeb: dealing with large numbers in C Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2019-10-21 11:32 +0800
Re: Challenge for Feeb: dealing with large numbers in C Autist <autist69@gmail.com> - 2019-10-29 15:15 +0100
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