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Author Topic: xxHash  (Read 408 times)

Vortex

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xxHash
« on: January 22, 2023, 07:55:13 PM »
Quote
xxHash is an Extremely fast Hash algorithm, processing at RAM speed limits. Code is highly portable, and produces hashes identical across all platforms (little / big endian). The library includes the following algorithms :

XXH32 : generates 32-bit hashes, using 32-bit arithmetic
XXH64 : generates 64-bit hashes, using 64-bit arithmetic
XXH3 (since v0.8.0): generates 64 or 128-bit hashes, using vectorized arithmetic. The 128-bit variant is called XXH128.

https://github.com/Cyan4973/xxHash
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Biterider

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Re: xxHash
« Reply #1 on: January 22, 2023, 08:15:15 PM »
Thanks Vortex
Very useful information!  :thumbsup:
The benchmark data is very interesting.
Let's see if we can use them...

Biterider
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jack

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Re: xxHash
« Reply #2 on: January 22, 2023, 10:03:42 PM »
had look at the collisions test
Quote
The test requires a very large amount of memory. By default, it will generate 24 billion of 64-bit hashes, requiring 192 GB of RAM for their storage
that's a bit more memory than what my PC has  :biggrin:
one thing that has always bothered me about hash tables is collisions, how you deal with a collision?
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LiaoMi

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Re: xxHash
« Reply #3 on: January 23, 2023, 02:42:40 AM »
:tongue: :thup:
Hash tables for ultra fast dictionaries - http://masm32.com/board/index.php?topic=9754.msg107371#msg107371
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jj2007

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Re: xxHash
« Reply #4 on: January 23, 2023, 05:45:32 AM »
Have you noticed that there is a big difference between searching with Google vs using Forum search?

Google finds 12 matches for "exgetsel" (with quotes) in the whole Internet.
Forum search finds 18 matches, in this forum only.

How could this be improved using hash tables?
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NoCforMe

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Re: xxHash
« Reply #5 on: January 23, 2023, 06:00:02 AM »
So maybe the mighty vaunted Google ain't the miraculous collection of algorithms that it's cracked up to be, eh? Who woulda thunk it?

(OTOH, it's a hell of a lot better than Duck Duck Go, which I no longer use: I love its privacy protections, but its search results are quite inferior to Google's.)
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jj2007

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Re: xxHash
« Reply #6 on: January 23, 2023, 06:02:43 AM »
The explanation is that Google uses fast hash tables, while forum search uses slower algos.
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NoCforMe

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Re: xxHash
« Reply #7 on: January 23, 2023, 07:18:19 AM »
So the tortoise wins the race ...
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jj2007

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Re: xxHash
« Reply #8 on: January 23, 2023, 07:50:22 AM »
Yep. Google uses hash tables, and therefore can find only full words. No partial search :cool:
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mineiro

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Re: xxHash
« Reply #9 on: January 23, 2023, 12:27:35 PM »
You can check this link, sound that authors are talking about:
https://encode.su/threads/2556-Improving-xxHash
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I'd rather be this ambulant metamorphosis than to have that old opinion about everything

jj2007

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Re: xxHash
« Reply #10 on: January 23, 2023, 07:09:21 PM »
Quote from: mineiro on January 23, 2023, 12:27:35 PM
You can check this link, sound that authors are talking about:
https://encode.su/threads/2556-Improving-xxHash

Bulat Ziganshin definitely knows what he is talking about, he is the author of FreeArc, the best archiver ever :thumbsup:
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