Author: Heiner Marxen
Date: 06:50:27 07/23/01
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On July 23, 2001 at 02:25:50, Uri Blass wrote: >On July 22, 2001 at 22:44:46, Heiner Marxen wrote: > >>On July 21, 2001 at 15:02:43, Uri Blass wrote: >> >>4k3/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - acn 718366; acs 8; bm e4; ce 32756; dm 6; >>pv e4 Kf8 Qg4 Ke8 Qg7 Kd8 Bb5 Kc8 Bc6 Kd8 Qd7#; > >Here chest is faster than chessmaster in finding the shortest mate. :-) >chessmaster6000 cannot see mate in 6 even after some minutes because of null >move pruning unless I asked it to search for mate in 6. > >The problematic line from chessmaster's point of view is: >1.e4 Kd7 2.Qg4+ Kc7 3.Qg7+ Kc6 4.d4 Kb6 5.Qd7 when black is in zunzwang. > >Usually chessmaster is faster than chest in finding the shortest mate but it >does not know that the mate that it found is the shortest mate. Yes, and this is what makes Chest slow, most of the time: proving that all those shorter mates do not exist. >I guess that the times of chest in every problem is for finding all the >solutions and in this case chessmaster has a clear advantage because it is happy >with finding 1 solution. Normally (for Chest that is with composed chess problems with just one solution) this is not a big thing. The average solution time would reduced by a factor of 2, or even less, since the non-solution moves often are significantly faster to compute. Here, where we have 2 or sometimes even 5 solution moves, it could be a factor of 4. That would change the times significantly. OTOH, it is nice to know all solutions as a reference point. >Chessmaster results in finding the shortest mate in the same problems in >comparison to chest: > >-, 8 >4, 190 >2, 180 >2, 129 >13, 141 >4, 157 >17, 128 >6, 182 >2, 182 >52, 250 >25, 203 >108,278 >125,178 >- ,186 >24 ,216 >6, 291 >38, 197 >87, 179 >5, 230 >25, 213 >19, 200 >103,357 >71 ,324 Thanks for the info! That doesn't look bad for Chest. What CPU/memory did you use for Chessmaster? >Chessmaster also found mate in 8 in all the other problems that were posted >except one > >[D]4k3/pp2p3/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1 That one is still busy computing :-) Regards, Heiner
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