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Subject: Re: When to do a null move search - an experiment

Author: Vincent Diepeveen

Date: 13:50:56 04/28/04

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On April 28, 2004 at 15:03:41, Gerd Isenberg wrote:

>On April 28, 2004 at 12:12:17, Vincent Diepeveen wrote:
>
>>On April 28, 2004 at 11:32:00, Gerd Isenberg wrote:
>>
>>>On April 28, 2004 at 09:44:01, Vincent Diepeveen wrote:
>>>
>>>>>I tried double nullmove suggested by Vincent too, without any precondition like
>>>>>eval - margin >= beta. Vincent is probably right - it seems to work great, and
>>>>>solves a lot of test positions a few percent faster. But with some positions,
>>>>
>>>>And how many plies does double nullmove on average search deeper in a normal
>>>>chess position?
>>>
>>>It looks like iterations terminate about 5-10% earlier on average.
>>>I fear my BF isn't that good to earn an additional ply in standard matches.
>>>
>>>My impression with your really great double nullmove idea is
>>>that it doesn't work so good in critical and probably game decisive positions,
>>>even in early middlegame root positions. But of course that may be due to my
>>>implemetation and sideeffects with other things in my search.
>>
>>this is a big nonsense and you know it.
>
>Sorry Vincent, no - simply my vague impression.
>Similar to some more additional knowledge, which slows you down a bit, but helps
>to find some moves one ply or even more plies earlier.
>
>Of course i have to investigate it a bit more and play some matches.
>
>>
>>theoretical chess studies which never come onto the board you cannot call
>>'critical game deciding positions'.
>>
>>You show up with some insane positions where uncommon passer knowledge, checks
>>or pawn evaluation are decisive in terms of whether you find a winning move or
>>not and you use that to test 'zugzwang'.
>
>I thought BT-test positions are from some gm matches?

They just have tried to locate anti-positional near to random positions where
computers had problems with AFAIK and nullmove especially.

So positions where bruteforce is not doing bad.

So if you do less selective search somehow in such positions, especially near
the leafs knowing the poor qsearch from isichess, i am sure that will be
helpful.

As long as you do not realize that, then we will continue misunderstanding each
other here.


>Anyway, there are some other positions i tried so far from my favourite testset,
>even positions from games IsiChess played, like this am position.
>
>6k1/4bppp/2p3n1/5Q2/1qPB4/1P1R1BP1/r6P/7K w - - am Qc8



>>
>>Both your positions have nothing to do with zugzwang in absolute respect. Just
>>get a fullwidth search with singular extensions and in your testset positions it
>>will outgun anything you do with nullmove, i'm sure of it.
>
>Ok, i will try and see.
>
>>
>>As long as we are not speaking at the same level with each other, i can't help
>>it that fullwidth+singular extensions solve anything you show up with sooner.
>>
>
>I fear with search topics and parallel search i'll never reach your level and
>brilliancy ;-)
>
>Cheers,
>Gerd



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