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Subject: Re: Fruit finds mate in 45 Movei find it faster

Author: Joachim Rang

Date: 07:49:01 11/03/05

Go up one level in this thread


On November 03, 2005 at 10:39:17, Uri Blass wrote:

>On November 03, 2005 at 09:21:17, Uri Blass wrote:
>
>>On November 03, 2005 at 08:40:02, Ignacio Santos Crespo wrote:
>>
>>>Hi Uri,
>>>
>>>Thank you for your answer. The following position is interesting: Fruit crash
>>>and Movei crash after depth 16.
>>>
>>>Mate in 69
>>>
>>>[D]1K1n2q1/1p4pR/1prPPpPn/1RB1p1rP/8/1B2p3/2p2b2/1k2N3 w - - 0 1
>>>
>>>Regards,
>>>Ignacio.
>>
>>
>>Thanks for posting it.
>>
>>I could verify that the public version crash in console mode at depth 16
>>when latest private version even crash at depth 14.
>>
>>The question is also what is the reason that fruit crashed.
>>If it crashed because the interface cannot get long pv then it may be a bug in
>>the interface but if it crashed because of another reason then it is a bug in
>>the engine.
>>
>>Uri
>
>More details
>
>The version that was compiled by Dan Crobit crash at depth 14
>slower version that was compiled by me does not crash and can get even depth
>17(maybe the reason is that I added some printf that print the maximal ply every
>time that it get it and for some reason the bug with printf does not lead to
>crash but only to high depth that is not logical(I get branching factor that is
>close to 1.2 or 1.3 at depth 14-17)
>
>the maximal selective depth of movei is 100 so it cannot see mate in 69
>
>At depth 13 the maximal selective depth that movei search in this position is 97
>At depth 14 it get selective depth of 100 and it seems that the version that Dan
>Corbit compiled crash near the time that it gets selective depth of 100 plies.
>
>I suspect that the problem may be that my arrays are too short at some point
>I tried to reduce the maximal search depth to 99 and it did not help.
>
>I tried again to reduce the maximal search depth to 97 and it did not crash but
>it also does not get depth 17 fast like the previous version and at the time of
>posting it only started depth 16 that is clearly logical because I do not expect
>branching factor of 1.2 and branching factor that is slightly more than 2 is
>clearly more logical.
>
>
>Uri


it has to do with the compiler. Fruit compiled by Bryan Hofmann (official
version ) crashes while other dev-compile from me does not. Probably some kind
of optimization which can cause a crash in rare circumstances.

Joachim



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