Author: Ed Trice
Date: 05:36:49 01/08/04
Go up one level in this thread
On January 08, 2004 at 04:27:01, martin fierz wrote: > >i don't know whether that is correct. IIRC your experiments were done with >wyllie (a weak program) and with an old version of kingsrow (which was >absolutely no good at winning these kind of positions - i know this because i >discussed this with the author of kingsrow, ed gilbert - of course, you couldn't >know this!). Martin, you may recall I asked for volunteers to participate in this experiment when I posted on George Miller's BBS. I was greated with cricket chirps. Since Murray Cash had also created a Distance To Conversion database (DTC) I was very curious to get some data about how it would perform against the Perfect Play Lookup database: again, no real interest was demonstrated on Murray's end. I would like to point out the winning side in each case had a 7-piece database which would allow them to avoid considering any move that lost or game away the draw as the game tree was built. Ed Gilbert felt his program could win, and it did not. Roberto felt his program could win, and it did not. This was an important result! For the first time, it was discovered that a winning position in the game of checkers was difficult enough to be drawn in practice. >after some discussion with ed gilbert, his program is now much better at >converting wins. Yes, AFTER this was demonstrated to him. How was I supposed to play the program version that he improved AFTER this experiment while we were conducting the experiment? >you should try again against his latest version 1.14l; if that >can't win against the perfect play database then you have a point! > Well the entire solution to this 253 ply win has been published now. I dont understand how you can diminish a result shown against two grandmaster strength checker programs. Yes, Wyllie is the weakest of the lot, but it still would easily exceed the minimum requirements for grandmaster status. >i noticed that there is a downloadable version of WCC gold plus now, >unfortunately for this purpose it only has a 6pc perfect play database. can you >give me a couple of hard 6-piece wins that i can try against cake? In my experience the even database wins are not that difficult. For 3 against 3 (3x3) you are basically playing the longest form of second position, which has a straightforward algorithm to execute the win. You just "change the guard" on the uncrowned men, crown all of your own pieces, then force the minority king out of the double corner in an easy-to-demonstrate fashion. Even middlegame heuristics should be able to resolve this. The longest win for 3x3 = 167 plies bk: 25 bc: 5,9 wk: 18 wc: 17,30 black to move and win. I think it just plays into a 3x2 in a few plies, but it is one of the longest 3x2 wins. You and I already played a 3x2 test in 2001, and we learned that these are able to be handled by contemporary programs. If you would prefer, we can play a 4x3 via messenger if you want. These are much more interesting and difficult. >in one of the games i played between cake 6-pc and WCC gold plus, cake got into >a winning 3-2 ending where WCC announced that it would lose in 75 ply, and cake >needed 79 ply to finally win (it twice played a move that left the >distance-to-win unchanged) - not bad; but of course it probably gets >exponentially harder with distance-to-win. > That is also the old 'Al Lyman' opening book with lots of bad play in it. I have the tournament edition of the opening book. I am not sure if this will make a difference or not.
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