Author: Robert Hyatt
Date: 18:17:00 03/27/00
Go up one level in this thread
On March 27, 2000 at 15:02:03, Dann Corbit wrote: >On March 27, 2000 at 01:28:15, Kai Skibbe wrote: > >>Crafty 17.07 has special code for detecting rookpawns and wrong bishop. >>But in the following position Crafty evaluates the position with a positive >>score. >>Why is the score of Crafty positive ? >>I have tested the position with the fritzengine of Crafty 17.07 with 32MB >>hashtables on a Celeron 500MHz and no tablebases. BTW with only two pawns on >>a-file Crafty shows a drawscore. >> >>[D]k7/8/P7/P7/P7/8/1K6/B7 w - - 0 1 > >Actually, it is a little bit funny. Crafty drops the evaluation back to zero as >it sees the pawn eaten. Then it gets its hopes up for the next pawn, and sees >it eaten. Finally, on the third pawn, it got its hopes up again, but I was not >patient enough to see them dashed again. > >Crafty v17.10 > >White(1): epdpfga epd.epd epd.out >PFGA: EPD record: 1 > time surplus 0.00 time limit 16:39 (16:39) > nss depth time score variation (1) > 13-> 0.31 1.56 1. Kb3 Ka7 2. Bd4+ Kxa6 3. Kb4 Kb7 > 4. Kb5 Ka8 5. a6 Kb8 > 14 0.44 -- 1. Kb3 > 14 0.46 ++ 1. Kb3!! > 14 0.68 0.00 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 > 14-> 0.87 0.00 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 > 15 0.88 ++ 1. Kb3!! > 15-> 1.15 0.39 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 > 16 1.16 ++ 1. Kb3!! > 16-> 1.42 0.78 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 > 17 1.65 ++ 1. Kb3!! > 17-> 1.93 1.17 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 > 18 1.95 ++ 1. Kb3!! > 18-> 2.25 1.56 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 > 19 2.86 ++ 1. Kb3!! > 19-> 3.13 1.95 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 > 20 3.53 ++ 1. Kb3!! > 20-> 3.77 2.34 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 > 21 4.19 ++ 1. Kb3!! > 21-> 4.46 2.73 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 > 22 5.25 -- 1. Kb3 > 22 7.85 0.00 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 <HT> > 22-> 8.29 0.00 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 <HT> > 23 8.31 ++ 1. Kb3!! > 23-> 6:50 0.39 1. Kb3 Ka7 2. Kb4 Kxa6 3. Bd4 Kb7 4. > Kb5 Ka8 5. a6 Kb8 6. a5 Ka8 7. a7 Kb7 > 8. a8=R Kxa8 <HT> > 24 6:50 ++ 1. Kb3!! > time=7:22 cpu=99% mat=6 n=100206329 fh=99% nps=226230 > ext-> checks=16150019 recaps=0 pawns=151201 1rep=968509 thrt:0 > predicted=0 nodes=100206329 evals=96649 > endgame tablebase-> probes done=11330 successful=11330 This is caused by the bishop 'leaving'. It found a way to sac the bishop, and since you don't have even simple databases like kpk, it won't realize that the resulting ending is a dead draw... I don't get that odd behavior at all here, with databases turned on...
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