Author: Bernhard Bauer
Date: 23:58:38 06/01/99
Go up one level in this thread
On June 01, 1999 at 11:56:42, Christophe Theron wrote: >On June 01, 1999 at 05:51:49, Bernhard Bauer wrote: > >>You surely know how Crafty uses null move. From search.c you can see: > >(snip) > >>Bob Hyatt doesn't use null move if there are "few" pieces on the board. That >>could be viewed as low mobility. Of course other views are possible. > >This rule is simple but too simple. There are ways to get much better >performances in the endgame. But of course you have to live with a few >"holes"... > > >>Zugzwang detection is another thing that may help. > >But "zugzwang detection" does not exist! If somebody is able to write a >"zugzwang detection" routine, then the problem is solved. But there is no easy >way to detect that a side is in zugzwang, except by doing a search. And the cost >is too high. > > >>This "smart" choice makes you (and the users of your program) sad when your >>program fails to solve a certain position. > >I keep an algorithm when it makes me more happy than sad. :) > > >>>>The explanation "the computer can't do it" has proven wrong in decades. >>> >>>I don't understand why you say this... Did I say that the computer can't do it? >>>My program does it for example. >>> >>No you haven't said this. I do not argue against you. I simply don't like the >>holes in the programs. I want them to disapea. > >Don't you think I want the same? > >But "holes" are not the only problems chess programs have to face. You look >stupid when somebody finds a hole in your program, but you look also stupid when >your program is not able to compute deep enough to find a combination that other >programs see quickly. > >Don't focus too much on holes. If you do, then what you will get is a simple >alphabeta program with no selection at all. There will be no holes, but it will >takes ages to find simple things... > > >>>>The question remains: what is the best way to do it. There are ways that will >>>>not slow down your program and will succeed in other positions. >>> >>>I am all hears. Tell us how it is possible. >>> >>See above and have a look at Tiger. As Tiger solves the 2-mover you have >>allready implemented something thats better than in Fritz. > >But Tiger fails also badly on some other positions... And you would complain if >you would find them... So it's a neverending story. > > >>>>So I hope you can understand my point of view. >>> >>>Not if you tell me that I'm taking poor decisions. >>> >>A decision that leads to the wrong result for the gain of speed is poor. >>Finding a result in a somewhat long time is better than finding it never. > >I agree. That's why some of my selection algorithms are enabled only in the >deeper parts of the tree. I can miss something, but with longer time I will not >miss it anymore. > > > > Christophe Thank you for your contributions which have clarified a lot. I think we are allready agreeing. The whole field is difficult, but there are many programs in development and the programs become better. I wish you good luck for the WCC. Kind regards Bernhard programs in development - and
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