Author: Tom King
Date: 23:30:28 05/07/01
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On May 07, 2001 at 18:32:29, Robert Hyatt wrote: >On May 07, 2001 at 16:48:41, Tom King wrote: > >>Hi all, >> >>there's been a few postings recently about strategies for programs to >>effectively order moves at the root of the search. One strategy which is quite >>interesting is the "order by nodes searched" heuristic, used by Crafty (and >>maybe others). Currently, my program, Francesca, uses a very simple "order by >>eval()" heuristic for ordering root moves. >> >>As a test, I played a series of games between the standard version of my >>program, and a version which uses a "order by nodes searched" heuristic for >>ordering root moves. I set these two versions playing blitz, last night. When I >>just checked, they had played 130 games, and each had scored 50%. Each had won >>37, lost 37, and drawn 56. Amazing that it should end so even! >> >>It's difficult to draw any conclusions from this. >> >>Probably more games are needed to see if "order by nodes searched" really helps. >>My hunch is that it may be a win at slower time controls - move ordering becomes >>more important the deeper you search.. [this reminds me of the time back in 1995 >>when the move ordering in my program was very poor.. didn't seem to matter too >>much at blitz, but at slower time controls, the search just ground to a halt. I >>remember (fondly) how I made some improvements to Francesca's move ordering, and >>suddenly she was searching throught the deeper plies 10 times quicker! Ah! great >>days..] >> >>Rgds, >>Tom > > >The way to test is fixed-depth searches with both approaches. One will give >slightly smaller trees. this is not a _big_ win, just a win. (It _can_ be a >big win in some cases, and once you do a parallel search it will be an even >bigger win... Hmm.. I'll persevere some more with this idea. More games, different time limits, do some test suites, and see what I find. Certainly, it doesn't seem *worse* than my current scheme, just not better! Rgds, Tom
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