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Subject: Re: Is improvement from hash tables in middle game linear or exponential?

Author: Uri Blass

Date: 08:08:11 12/20/03

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On December 20, 2003 at 10:13:18, Vincent Diepeveen wrote:

>On December 20, 2003 at 08:43:37, Thomas Mayer wrote:
>
>>Hi Vincent,
>>
>>>I did 2 experiments:
>>>
>>>experiment A) I ran diep at 460 processors with 115MB hashtable *in total*
>>>experiment B) Same diep version at 460 processors with 115GB hashtables.
>>>
>>>Note hashtable means transpositiontable here. Each processor had local 4.2MB
>>>pawnhashtable and each processor had local 32MB evaluation table.
>>>
>>>MB = 10^6 , GB = 10^9
>>>#probes   = 4
>>>entrysize = 16 bytes
>>>position  = r4rk1/p1q1nppp/b2b4/2nP4/1P3p2/P1N2N2/B1P3PP/R1BQK2R w KQ -
>>>
>>>What is the expected outcome?
>>
>>well, there are several unclear facts - e.g. how to usage of 460 processors is
>>different to the usage of 1 processor etc.
>>
>>Anyway, let's try a guess and take the idea of Christoph Theron that hashtable
>>doubling is about 7 Elo... We have 10 doublings, so 70 Elos expected... Doubling
>>in speed is expected with around 60 Elos... So I expect a speedup of about
>>120-150%... How far am I away ?! :)
>>
>>Greets, Thomas
>
>i don't want any elo answer, that's bullshit of course. Above 12 ply (without
>forward pruning and with some extensions and checks in qsearch) another ply
>matters shit. The question asked here is: "what does it matter for search
>depth".

speedup of about 120-150% if you have branching factor of 2.5-3 means almost 1
ply deeper.

Uri



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