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

Author: Gerd Isenberg

Date: 12:03:41 04/28/04

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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?
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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