Author: scott farrell
Date: 23:15:36 01/12/04
Go up one level in this thread
On January 13, 2004 at 00:00:14, Uri Blass wrote: >On January 12, 2004 at 20:05:11, scott farrell wrote: > >>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 > >I do not understand it. > >Why maxthreat of Re5 is 0 when maxthreat of the illegal Ke4 is 1? >both threat the pawn at f5 and if we talk about new threat then they do not have >a new threat. yeh, maxThreat is only the maximum piece that can be attacked after the move is made, Its not SEE at all, I guess Re5 should return 1, attacking the pawn. I think maxThreat is not used much these days, but still in the debug. I'll check Re5 anyway. > >I also do not understand why threat against the king is 9 when SEE of exposing >the king to check is -50. > Maxthreat doesnt differentiate between kings and queens, its only to detect moves that are threatening, as opposed to actually capturing anything, if some threats a king its nearly the same as threat to a queen, you better do something about it - or probably lose the game. I guess you saw the nice 1.0 SEE+ gain for Rxf5 - you have to like that like. >Uri
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