Author: Robert Hyatt
Date: 15:03:42 09/17/04
Go up one level in this thread
On September 17, 2004 at 15:50:38, Dann Corbit wrote: >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. No, but if _both_ solutions have a common position, where the right move is played first by the correct player, and the second player wastes a few moves to force the game back to the initial position before forcing the win, it can't be good. As a human I would _never_ claim that the longer path is equivalent once I noticed that it just adds 4 moves to the _front_ of the correct winning plan. If it was not for the fact that the correct PV is a part of the longer PV, I'd buy your argument, but that isn't the case here. The correct move is played after wasting moves to force a repetition back to the starting position...
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