Author: Inmann Werner
Date: 04:15:57 11/03/98
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>>********* >>I tried something with null move. >> >>Problem: you can make a mate with the next move, but the opponent checks you as >>long as it goes beyond the horizon. >>I now only talk about this specific problem. I think, it often occurs and know, >>that a "solution" for this problem does not stop horizon effect all. >> >>My thought: When the opponent is on move, I do a null move and one own move and >>then quiet search. If a mate occurs here, I remember it, and pass it to the next >>alpha_beta recursion which is my move. Only if a am checked at this time, I >>extend 2 moves (not only one for the check) as long as extensions are allowed. >>(Max Extensions...) >>So I only extend if I can mate in one and the opponent slides out with a check! >>There are also some limitations when doing the special null move, but there I am >>experimating. >> >>My position above then gets solved at ply 6!!!!! >>I tried some other positions with heavy threats and checks, where no real mate >>can be made (worse for my algoritm). There it slows down about 10%, because it >>looks deeper in maybe interesting things which in this case do not work. >> >>I must say, that I implemented above 3 hours ago, and 3 hours testing is not >>much, but it is worth to think about. >> >>Werner > > >my advice is "caution" doing this. IE Crafty finds this at depth=10, about >10 seconds or so on my ALR. It's not hard to make it find it at depth=6 or >7. But would it play better in games? No... it is *easy* to over-extend and >find wonderful tactics but get killed positionally... But that would be a principle problem of extensions. If I do not extend in any case, I can fasten up my program extremly, getting 1 ply deeper. The question is, when to extend. Many say, at checks and beats on the same field, because here it gets interesting. I do so, and the search slows down. Gets the program then a worse play? Same I thought about mate threats and extensions. Aren´t they worth an extension? Werner
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