Author: Johan de Koning
Date: 18:08:00 09/30/03
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On September 29, 2003 at 03:41:24, Tim Foden wrote: >On September 29, 2003 at 03:13:13, Johan de Koning wrote: >>Anyway, I think I'll skip the experiment with fully normalized TT entries. >>(That's with inactive files removed, and the remaining files flipped/sorted >>into canonical form). That would be good for a complete retrograde analysis, >>but it won't beat alpha-beta on a fixed starting position. > >As Uri pointed out, if there are any empty files, and all pawns in groups >bounded by the edge of the board and any empty files can't move, then they could >be treated as not being there any more, which could improve the gain from the >fully normalised TT entries in a main search?? Yes, I was thinking of Uri's proposal. 1. Replace blocked file clusters with empty files. 2. Replace adjecent empty files with a single empty file. At this point, I think, Uri's Fibonacci enumeration applies. 3. Flip each cluster left-right, select the "better" one. 4. Sort clusters most "better" to least "better". 5. Apply 1...4 to a W-B mirror of the original position, select if "better". Where "better" is defined by some unambiguous recipe. >It may also be possible to apply some form of combinatorial approach once at >least one empty file has appeared, which could speed things up quite a lot I'd >think. That would certainly be interesting, if you like headaches. Though I can think of one simple, not systematic approach: any cluster that draws in an even number of plies can be scratched, as in steps 1 and 2. Or less simple: any cluster that wins against an arbitrary number of moves and null moves can be used as a lower bound for the entire position. Hmmm, it looks like many more days can be wasted on the Pawn Game. :-) ... Johan
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