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Subject: Re: EGTB: Until what depth ?

Author: Tony Werten

Date: 11:43:32 03/29/01

Go up one level in this thread


On March 29, 2001 at 14:24:14, Robert Hyatt wrote:

>On March 29, 2001 at 14:10:06, Tony Werten wrote:
>
>>On March 29, 2001 at 09:14:06, Robert Hyatt wrote:
>>
>>>On March 29, 2001 at 04:37:19, Tony Werten wrote:
>>>
>>>>Hi all,
>>>>
>>>>until what depth do various programs probe the tablebases ?
>>>>
>>>>cheers,
>>>>
>>>>Tony
>>>
>>>
>>>With Crafty, if I am doing a 14 ply search, I probe until depth > 14.  Since
>>>in 40/2hr games I typically search to depth 13/14 in the middlegame, that is a
>>>good limit.  If I do an iteration to 19 plies, then I probe to 19 plies.
>>
>>That's what I'm doing actually. I tried probing in qsearch (only first couple of
>>ply) but in testpositions my harddisk would go nuts. OTOH in testpositions you
>>don't have previous positions that would already have excluded certain
>>searchpaths.
>>
>>In matches it works (probing first plies in qsearch) until the opponent does a
>>couple of unexpected moves.
>>
>>Same seems to happen when probing everywhere in full search ( including
>>extensions )
>>
>>In the dutch championships I got my egtb code working the second weekend and I
>>turned it on including unlimited probing in qsearch. After 12 moves or so, I got
>>out of book and spend 8 min on the search. I got 2 egtb hits while in the
>>rootposition there were 30 pieces on the board ( I had recapture extensions).
>>Then I got the idea that it might not be usefull to probe that much.
>>
>>Tony
>
>
>Don't forget the _obvious_ limits:
>
>1.  only probe after a capture that takes you to 5 or fewer pieces on the
>board.
>
>2.  never probe in other circumstances.  IE if you _already_ have 5 pieces
>on the board, there is no sense in probing, because the capture that dropped
>you to 5 pieces would have been a probe hit and you would not still be
>searching.  Since you didn't have the right tablebase _then_ you are not going
>to have it _now_.

Didn't think about the second one because until now I've always had all the
tables. Might be a good idea to put it in though.

Tony




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