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Subject: Re: Problem searching too deep!

Author: Sune Fischer

Date: 06:30:48 05/28/02

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On May 28, 2002 at 09:09:18, Daniel Clausen wrote:

>On May 28, 2002 at 04:05:47, Sune Fischer wrote:
>
>>I believe it is then safe to stop the search at 150 plies, that's 50 plies left
>>for extensions(!), it will simply have to do, even if I get a crash in 1 of
>>10000000 games ;)
>
>If you'd be in my programming team, either you or me would be looking for a new
>job now. ;) A simple additional if-statement at the beginning of search makes
>this 100% correct in all cases and slows down your engine by a _very_ small
>factor. So basically you're just careless here - and therefore maybe also
>careless in other places. ;)
>
>Remember that even though these small speedups do add up over time (and maybe
>give you an additional +2 ELO boost in the next 10 years *grins*) the risk for
>crashes or misbehaviours also adds up. And Murphy will make sure it will happen
>during the most important game. =) [should it happen during a game against my
>engine (in the future.. maybe..) I'll remind you of this thread =)]
>
>HTH :)

"careless" :)
Hmm, I don't know. I need to extend ~100 plies(!!) to get a crash for a total of
200 plies search!
Can you come up with any kind of position that would even slightly challenge
this limit? To get many extensions you need checks or so, but then the position
won't transpose as good (because it won't be blocked pawns), so really you need
maybe 170 extensions in a 30 ply search, in all it's extremely unlikely.

I think that has to be some kind of a record if so, surely it would mean a tree
explosion or really bad extension rules.

I also have the maximum number of pseudo legal moves set to 255, this must be  a
potential bug too then?
Well I'm not going to check before adding a move if there is still room, call me
careless if you must ;)

These are the only known limitations I have, anything else shouldn't crash if
the position is technical legal.

-S.

>Sargon



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