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Subject: Re: Does crafty stop calculating SEE after capturing a king?

Author: scott farrell

Date: 17:05:11 01/12/04

Go up one level in this thread

On January 12, 2004 at 17:34:52, Uri Blass wrote:

>I do not see when it happens in crafty and note that it is not only a question
>of speed when it is not clear what is faster and if I understand correctly
>crafty may be wrong when a sequence of captures that is finished in trading
>kings happens and it may happen in the endgames.
>
>[D]8/5r2/5k2/3R1p2/5K2/8/8/8 w - - 0 1
>
>Rxf5+ is a good capture but based on SEE that let trading kings it can be
>pruned.
>
>Uri


thanks uri/sune, added some stuff about a king,

my acutal check was if king is capturing, and -stm still has pieces in the
capture list, return -king for that part. I also added the dont xray the king,
but I didnt see any effect - but clearly it is smart.

My goal is to have 2 SEE, one fast, and one smart.

output from chompster:

the key is:
maxthreat/SEE+/SEE ala crafty/NA

as you can see it scores the Kxf5 as +1, and kxf5 as -50, interestingly with
checks in the qsearch either way found kxf5+ with the same 33 nodes. I think
crafty might need 2 plies instead of one, with an incorrect SEE and no checks in
the qsearch.

notice RE5 says 0 on both SEE and SEE+, I think SEE (ala crafty) just minimax's
the king swap and accidently gets the right score.

8/5r2/5k2/3R1p2/5K2/8/8/8/ w - - 0 0
normal moves:
RD8 (D5D8) , maxThreat=0/0/0/0
RD7 (D5D7) , maxThreat=0/-5/-5/0
RD6 (D5D6) , maxThreat=9/0/0/0
RA5 (D5A5) , maxThreat=0/0/0/0
RB5 (D5B5) , maxThreat=0/0/0/0
RC5 (D5C5) , maxThreat=0/0/0/0
RE5 (D5E5) , maxThreat=0/0/0/0
RxF5 (D5F5) , maxThreat=9/1/-4/0
RD4 (D5D4) , maxThreat=0/0/0/0
RD3 (D5D3) , maxThreat=0/0/0/0
RD2 (D5D2) , maxThreat=0/0/0/0
RD1 (D5D1) , maxThreat=0/0/0/0
KE5 (F4E5) , maxThreat=9/-50/0/0
KxF5 (F4F5) , maxThreat=9/-50/-4/0
KG5 (F4G5) , maxThreat=9/-50/-50/0
KE4 (F4E4) , maxThreat=1/-50/-50/0
KG4 (F4G4) , maxThreat=1/-50/-50/0
KE3 (F4E3) , maxThreat=0/0/0/0
KF3 (F4F3) , maxThreat=0/0/0/0
KG3 (F4G3) , maxThreat=0/0/0/0

• Re: Does crafty stop calculating SEE after capturing a king? Uri Blass 21:00:14 01/12/04
  • Re: Does crafty stop calculating SEE after capturing a king? scott farrell 23:15:36 01/12/04
    • Re: Does crafty stop calculating SEE after capturing a king? Uri Blass 00:02:52 01/13/04
      • Re: Does crafty stop calculating SEE after capturing a king? scott farrell 00:25:48 01/13/04

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