Author: Peter Fendrich
Date: 06:43:47 05/28/02
Go up one level in this thread
On May 28, 2002 at 09:30:48, Sune Fischer wrote:
>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
If I were you, I would at least put in something like:
#ifdef _DEBUG
if (ply >= MAXIMUM_PLY) printf("\nThis can't happen!\n");
#endif
Then at least you can easily trap crashes due to this impossible scenario.
From my experience things happen not beacause the program
does what I expect it to do but rather when it goes crazy... :)
Peter
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