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Subject: Re: Fruit X searches deeper than Shredder 7.04! :-)))

Author: Ulrich Tuerke

Date: 13:19:05 12/22/04

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On December 21, 2004 at 05:11:13, Uri Blass wrote:

>On December 21, 2004 at 03:53:49, Joachim Rang wrote:
>
>>On December 20, 2004 at 16:32:24, Jouni Uski wrote:
>>
>>>Shredder 8 reaches quite stunning averaga search dept. E.g. with only 15
>>>second/move average with Pentium 2400 and 128MB hash it averages 15,2 ply! For
>>>comparison Fritz Bilbao and Gandalf 6 reach both same 12,7 ply. No wonder
>>>Shredder beats them 13 - 7 and 14 - 6. Of course 2,5 ply is a lot difference!
>>>Is there any amateur or pro engine, which can equal Shredder in depth - Junior's
>>>half plys can be forgotten.
>>>
>>>Jouni
>>
>>Here is a 1-minute search on my Athlon XP@1540 MHz, with Shredder 7.04 default
>>and Fruit X with aggressive delta, futility and history pruning. Both engines
>>were analysing together under Arena. Compare the depth!
>
>I am surprised to read that fruit2 has history pruning.
>I understood that Fabien does not plan to implement history based pruning and
>here is the source of my misunderstanding:
>
>
>The reason is the following link:
>http://f11.parsimony.net/forum16635/messages/68164.htm
>
>Fabien claimed in that link:
>
>"Forward pruning in the main search is a separate topic that I don't intend to
>address now. If I ever do, I expect it will require years of work (same for a
>proper move ordering)."
>
>Note that I consider history based pruning as forward pruning in the main
>search.

Doesn't the history heuristic simply mean that moves which had often produced
cuts in the previous iteration will be tried as killers ?
If this is true, then history pruning does only change move ordering; so it's
clearly a backward pruning technique.

Did I get this wrong ?

Thx,
Uli

>
>It did not take me years to implement it and I was surprised that Fabien claimed
>that it will require years of work and maybe there is a misunderstanding about
>the meaning of forward pruning.
>
>Uri



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