Author: Vincent Diepeveen
Date: 08:18:37 05/27/04
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On May 26, 2004 at 13:49:38, Tord Romstad wrote: >On May 26, 2004 at 13:34:23, Robert Hyatt wrote: > >>I have used "IID" for years, but in a very restricted way, namely to handle the >>case along the PV where I have no hash move. I've never tried it _everywhere_ >>before, so have no data. But I intend to try to see if it is something that >>could work, or if it is a waste... > >I am fairly sure you will find that _everywhere_ is a waste. It is probably >not worth doing near the leaf, you have a hash table move to search, or when >a fail-low is most likely. Perhaps you should also use a somewhat bigger >reduction factor than in your "along-the PV IID". > >Note that it could also be interesting to look for good ways to make use of the >return value of the internal search. It gives a reasonably reliable estimate >of the value of a full-depth search, and can be useful as an ingredient in >pruning tricks. The most obvious (and entirely risk-free) case is when the >reduced-depth search returns a mate score. When this happens, it is clearly >not necessary to do a full-depth search. IID works only when your program is too inefficient. it used to work for years too for my checkers 10x10 program and initially even for diep. But then later it just didn't work anymore when i added some more knowledge to checkers 10x10 and improved its move ordering a bit. For DIEP it seemed to work in past for big depths, but when i improved move ordering around 1998-1999 it no longer worked anymore. I tested it in all type of different behaviours. Same is true for things like countermove and history table moves. They just do not work anymore when your program is getting more efficient. >Tord
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