Author: Uri Blass
Date: 03:19:35 02/07/01
Go up one level in this thread
On February 06, 2001 at 17:19:28, Heiner Marxen wrote: >On February 06, 2001 at 16:55:44, Uri Blass wrote: > >>On February 06, 2001 at 12:02:30, Heiner Marxen wrote: >> >>>On February 06, 2001 at 10:17:01, Paul wrote: >>> >>>>On February 06, 2001 at 08:59:10, Heiner Marxen wrote: >>>> >>>>>I have not yet tried with side to move switched ;-) >>>> >>>>I have :) ... I also get a mate in 7, is much more difficult tho :) >>>> >>>>Bxe4 B5xe4 Rb1+ Bxb1 Rd8 Bxc7+ Bxc7 Bxa7+ Kxa7 Ra5+ Ba6 Rgxa6+ Kb8 Bxc7# >>> >>>I like Rb6# more :-) >>> >>>Well, didn't that mate the wrong side? >>> >>>With side to move switched to white Chest does not find a mate in 11, >>>in only 80 seconds (K6-3/400 30MB hash). Therefore I suspect, this time >>>switching side to move is not much fun ;-) >>>(except in the way you handle it :-) >> >>chess playing programs may be faster than chest in this case. > >Sure, that happens all the time. > >>They can prove that there is no mate. >> >>Evaluation of mate against white at the end of the iteration is a proof that >>white has no mate. >> >>Proving that white has no mate in 11 is not a proof that white has no mate. > >Sure! I took it just as a hint, not as a proof. Sorry for not being clear. > >Chest has a bit support to find a mate against the side to move, by just >trying to solve a series of mates 1 ply deeper (option -x): >I just tried it with depth=6: > >After Rh8 - h1 ... > No solution in 6 moves. >After Rb3 - b1 ... > No solution in 6 moves. >After Bc8 - b7 ... > Solution (in 2 moves): > Be5 : c7 >After Bc8 - a6 ... > Solution (in 3 moves): > Be3 : a7 >After Bc8 - d7 ... > Solution (in 3 moves): > Be3 : a7 >After Bc8 - e6 ... > Solution (in 6 moves): > Bf5 : e6 > Be5 : h8 >After Bc8 : f5 ... > Solution (in 5 moves): > Rg6 - g8 >After Ba8 - b7 ... > No solution in 6 moves. >After Ba8 - c6 ... > No solution in 6 moves. >After Ba8 - d5 ... > No solution in 6 moves. >After Ba8 : e4 ... > No solution in 6 moves. >After Ba5 - b6 ... > Solution (in 6 moves): > Rg6 : b6 >After Ba5 - b4 ... > Solution (in 2 moves): > Be5 : c7 >After Ba5 - c3 ... > Solution (in 2 moves): > Be5 : c7 >After Ba5 : d2 ... > Solution (in 2 moves): > Be5 : c7 >After Rh8 - g8 ... > Solution (in 4 moves): > Rg6 : g8 >After Rh8 - f8 ... > Solution (in 6 moves): > Bd2 : a5 >After Rh8 - e8 ... > No solution in 6 moves. >After Rh8 - d8 ... > No solution in 6 moves. >After Rh8 - h7 ... > Solution (in 5 moves): > Rg6 - g8 >After Rh8 - h6 ... > Solution (in 5 moves): > Rg6 - g8 >After Rh8 - h5 ... > Solution (in 5 moves): > Rg6 - g8 >After Rh8 - h4 ... > Solution (in 5 moves): > Rg6 - g8 >After Rh8 - h3 ... > Solution (in 5 moves): > Rg6 - g8 >After Rh8 - h2 ... > Solution (in 5 moves): > Rg6 - g8 >After Rb3 - c3 ... > No solution in 6 moves. >After Rb3 : d3 ... > Solution (in 6 moves): > Be5 : c7 >After Rb3 - a3 ... > Solution (in 4 moves): > Be3 : a7 >After Rb3 - b4 ... > No solution in 6 moves. >After Rb3 - b5 ... > No solution in 6 moves. >After Rb3 - b6 ... > Solution (in 3 moves): > Be5 : c7 >After Rb3 - b7 ... > No solution in 6 moves. >After Rb3 - b2 ... > No solution in 6 moves. >After Ra7 - b7 ... > No solution in 6 moves. >After Ra7 - a6 ... > Solution (in 2 moves): > Be5 : c7 >Time (virt) = 236.180 sec (ca. 3.9 min) > >Still no proof of anything, but you can try to find a proof with Chest. >With more depth and time it might find a mate after all legal moves. > >Also, when processing an EPD batch, Chest first tries to find a direct mate, >and if not found, it tries to prove the side to move is lost, in the way >indicated above. It is better to use a mate finder and not a mate prover for the second side if the target is to be faster in proving mates. Uri
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