Author: Robert Hyatt
Date: 21:20:03 08/27/03
Go up one level in this thread
On August 27, 2003 at 22:12:54, Tom Likens wrote: >On August 27, 2003 at 14:01:18, Robert Hyatt wrote: > >>On August 26, 2003 at 18:42:59, Ricardo Gibert wrote: >> >>>In the Richard Lang interview at: >>> >>>http://www.beepworld.de/members37/computerschach/ >>>(Just click on the link "ChessGenius Classic 7" in the leftmost column. The >>>interview also appears in *English*) >>> >>>"For example I have never used capture searches and rely instead on a static >>>swap off routine." >>> >>>This seems to indicate that CG does not employ a qsearch. I also understand that >>>Junior does something similar. I wonder how this is done? I would presume some >>>type of accuracy tradeoff must be involved, but I wonder what? I'm very curious >>>about how this is all done and why doesn't everybody do it this way? >>> >>>How is all the effort that goes into creating a good eval compatible with such a >>>handling of non-quiescent positions? It just seems kind of wacky to me. >> >> >>I can tell you what I did in the 1970's. >> >>The issue is that the _last_ move in the search path is "iffy". IE if you >>just do a pure 4 ply search, no extensions, no q-search, the last move in your >>pv will _always_ be a capture of the most valuable piece that can be taken, >>whether it is protected or not (IE in a worst case, you end the PV with QxP, >>where in a real game, the opponent would the reply PxQ.) >> >>If you apply a SEE type exchange evaluation to the last piece moved, you >>stop this nonsense. Of course, that misses overloaded pieces and the like, >>but it is certainly possible that the errors that produces are not frequent >>enough to cause a problem. The tree is far more robust than I would have >>thought possible, until some recent testing has produced some amazing results. > >And yet my program *still* makes bad moves :) > >So any chance you will be publishing something in an upcoming issue >of the ICCA journal (or the ICGA as it is now known)? > >regards, >--tom Possibly. Either there or in an AI journal...
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