Author: Graham Laight
Date: 09:50:39 05/11/00
Go up one level in this thread
On May 11, 2000 at 10:43:57, blass uri wrote: >On May 11, 2000 at 10:20:34, Graham Laight wrote: > >>On May 11, 2000 at 10:07:56, blass uri wrote: >> >>>On May 11, 2000 at 08:33:26, Mogens Larsen wrote: >>> >>>>On May 11, 2000 at 05:36:42, blass uri wrote: >>>> >>>>>I also believe that other beta testers did not think about part of my productive >>>>>ideas for chess programs. >>>> >>>>Out of curiosity, what productive ideas have you been suggesting? >>>> >>>>Sincerely, >>>>Mogens >>> >>>I will repeat one idea that I posted here: >>> >>> >>>Many programs are null movers and they prune moves when they see no threat. >>> >>>I found that Crafty could not find some tactics in practical games because it >>>pruned threat mate moves. >>> >>>I suggested that before the decision if to prune by null move to check also if >>>there is a mate threat to bigger depth(If it seach d plies for regular threat it >>>can search d+1 or d+2 plies for mate threat) >>> >>>I think this will help crafty to see tactics when there is a mate attacks and I >>>think that crafty will not be significantly slower when there is no mate threat >>>because checking if there is a d+1 plies mate threat is easier than checking if >>>there is a d plies not mate threat). >>> >>>Crafty can call chest(a free program that is the best mate solver) to check if >>>there is a mate threat and chest is a very fast mate solver(it tries to prove >>>that there is no mate with the smallest possible tree and it helps it to see >>>that there is no mate very fast). >>> >>>I read that it is a slow searcher and search only 20000 nodes per seconds on >>>a slow hardware p166(I am not sure if I am right about the hardware) but it can >>>solve 1500 mate in 2 in one second. >>> >>> >>>Crafty on p166 needs significantly more than 1/1500 second in order to search 3 >>>plys threat when these threats can miss mate in 2 because crafty's evaluation >>>also has no idea if the position is mate so it may need more than 2d-1 plies to >>>see mate in d threat not only because of null move. >>> >>>Uri >> >>This is a good idea, but I don't think Bob will go for it. >> >>Firstly, it's difficult to know whether there's a possible mate threat. If there >>is, there's a high probability that a chess program would stumble upon it >>anyway. > >It is not so difficult to know when there is a mate threat > >There are positions when it is more common when the king is exposed >and it take less time to check if there is amate threat than checking if there >is another threat so crafty will not be significantly slower. > >> >>Secondly, I think Bob likes to control everything that's happening so that he >>can ensure that it's all done in the minimum amount of time. Having a cuckoo in >>the nest doing unpredictable things with unpredictable quantities of resources >>is hardly likely to please Bob, from my readings of his postings over the years. > >It is possible to control the time. >You can decide to call chest to search for a mate threat not more than 1/10 of >the time that you search for other threats(It will often search deeper and even >if it does not search deeper it can see mate threats that the regular search of >crafty does not see because of null move pruning because crafty is using null >move recursively) > >Crafty will be slightly slower in cases when there is no mate threats but the >fact that it will find some important tactics that it did not find before is >more important. > >Uri Perhaps chess programmers will have to accept an "object oriented" approach to programming to make their programs much better - with different programmers doing different objects. I have already stated my case that programmers should consider using knowledge management tools (I suggest http://www.haley.com might be a good place to start) because at least one top programmer has admitted that building the knowledge in a non-systematic way has resulted in the same knowledge being used more than once in evaluating position nodes. I remember in the 1970s when people would build a hi-fi system. They would get the turntable from one supplier, the tape deck from another, the tuner from another, the amplifier from another, and the speakers from yet another! Maybe we have to go this way in building "chess systems" to get the best possible players. -g
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