Author: Dann Corbit
Date: 12:50:38 09/17/04
Go up one level in this thread
On September 17, 2004 at 15:06:40, Uri Blass wrote: >On September 17, 2004 at 14:21:16, Dann Corbit wrote: > >>On September 17, 2004 at 11:42:38, Robert Hyatt wrote: >> >>>On September 16, 2004 at 19:48:59, Dann Corbit wrote: >>> >>>>On September 16, 2004 at 18:18:13, Robert Hyatt wrote: >>>> >>>>>On September 16, 2004 at 12:52:43, Dann Corbit wrote: >>>>> >>>>>>On September 16, 2004 at 07:37:01, Ricardo Gibert wrote: >>>>>> >>>>>>>Your post is a good example of what happens when one jumps to a conclusion >>>>>>>without taking the minimum amount of effort needed to understand what is really >>>>>>>going on. >>>>>> >>>>>>I disagree completely, also with everyone else. >>>>> >>>>>Taking a _longer_ path to win is counter to a tactical test idea. Clearly the >>>>>move given is bad, because it just extends the game and reaches the same >>>>>position a second time where the _real_ solution has to be played. That is >>>>>pointless... >>>>> >>>>>Otherwise a mate in 3 might turn into a mate in 40 if one side takes every >>>>>opportunity to first repeat a second time before making progress... >>>> >>>>The pv shown by Arasan leads to a win. >>>>If it lead to a draw or some other problem I would agree. >>> >>>You ask a student to add 2 + 2. >>> >>>He turns in the following: >>> >>> >>>sqrt(100) / sqrt(25) + log10(100) and solves that and turns it in with his >>>scratch paper. Do you give him credit? I do not. There are a zillion longer >>>ways to do something, such as a tree search in chess. Tactical solutions are >>>about the shortest way to win. IE if there is a mate in 8 and a mate in 10, the >>>correct answer is the mate in 8. >> >>There are often strange solutions to test problems (e.g. tossing a queen due to >>tablebase simplification). If a chosen move wins 100% of the time, and the >>program sees a clear solution, it is a winning move. A winning move cannot be >>said to be incorrect. It has exactly the same value as a winning move to a >>shorter solution. >> >>>If there are two equal ways to win, then yes, >>>either is correct. But to intentionally repeat a position makes no sense and I >>>give it a "zero" as it is pointless... >>> >>>If you want to count it right, that's ok, but I disagree and I won't. Otherwise >>>each WAC position probably has _multiple_ correct solutions... >> >>If a problem is not proven all the way to win/loss/draw then it is really open. >>If there are 10 moves that lead to a definite win, then all ten moves are >>solution moves. Including crazy moves like tossing a queen for a tablebase >>simplification. > >I disagree. >There are cases when there is only one solution that you can expect chess >programs without bugs to find and it is the right solution(tablebase win is not >a bug in chess programs so it can be included as a solution but a win by >repetition of the root position certainly incdicates a bug). > >WAC is used to test chess programs for not having bugs in the search and failure >should suggest a bug. > >If you include the stupid move of arasan as a solution then the wac test is >losing it's value to detect bugs. > >By your definition a lot of problems in WAC have more than one solution >I found 7 position with more than one solution in the first 20 positions simply >by using Fritz at 2 best move in 6 cases or by using my brain in one case to see >that white can force repetition and win later. > >2rr3k/pp3pp1/1nnqbN1p/3pN3/2pP4/2P3Q1/PPB4P/R4RK1 w - - bm Qg6; id "WAC.001"; > >1)Nh5 also wins and not only Qg6 > >r1bq2rk/pp3pbp/2p1p1pQ/7P/3P4/2PB1N2/PP3PPR/2KR4 w - - bm Qxh7+; id "WAC.004"; > >2)Qe3 also wins > >r4q1k/p2bR1rp/2p2Q1N/5p2/5p2/2P5/PP3PPP/R5K1 w - - bm Rf7; id "WAC.008"; > >3)Nf7+ Kg8 Nh6+ Kh8 Rf7 also wins > > >r2rb1k1/pp1q1p1p/2n1p1p1/2bp4/5P2/PP1BPR1Q/1BPN2PP/R5K1 w - - bm Qxh7+; id >"WAC.014"; > >4)Ne4 also wins > >1R6/1brk2p1/4p2p/p1P1Pp2/P7/6P1/1P4P1/2R3K1 w - - bm Rxb7; id "WAC.015" > >5)b4 also wins > >1k5r/pppbn1pp/4q1r1/1P3p2/2NPp3/1QP5/P4PPP/R1B1R1K1 w - - bm Ne5; id "WAC.017"; > >6)I suspect that b6 also wins. > >r2qkb1r/1ppb1ppp/p7/4p3/P1Q1P3/2P5/5PPP/R1B2KNR b kq - bm Bb5; id "WAC.020"; > >7)Be6 also wins If your engine choses one of those alternatives and shows a winning line, or a checkmate is found, then those are solutions. If two different moves clearly win, then the moves are equivalent in value. Unless a move ends in a proven checkmate (e.g. by Chest) then we do not really know if it is going to win, and so there is some doubt in it. There are (perhaps) some winning moves that are better than others. But until a forced checkmate is demonstrated, we really cannot know which one is better.
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