Author: Will Singleton
Date: 21:59:49 05/13/99
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On May 14, 1999 at 00:24:38, James Robertson wrote: >On May 13, 1999 at 23:12:41, Dan Homan wrote: > >> >>I've tried the mtdf algorithm a few times with no luck. It was >>always noticably slower than pure PVS. (For reference: mtdf is >>an algorithm which uses a series of null-window searches from the >>root to narrow in and find the true score of a position.) >> >>Today I tried mtdf again, but this time with more determination. >>It is an easy change to my program because all I need to modify >>is the loop that calls my PVS function from the root. Again, I found >>that it was much slower than normal PVS at first. However, >>by modifying the algorithm to use an adaptive step-size (meaning that >>I don't try neighboring (+/- 1 point) windows for re-searches but >>rather try to bound the score more efficently) and by >>reducing my score resolution from 1/100 th of a pawn to 1/25 th of >>a pawn, I got better results from mtdf than from pure PVS. >> >>I went from 277 correct solution on the WAC test set (5 sec limit on a >>Cel 400) to 281 correct solutions with mtdf. My rms solution time for >>both runs (with and without mtdf) were nearly the same. Of course, >>these tests are not really conclusive... For example I don't know how >>pure PVS will do with 1/25 th of a pawn scoring rather than 1/100 th. >>What this does indicate to me is that mtdf is a viable solution. Previously, >>I had assumed it would be very difficult to implement effectively. >> >>If I decide to commit to mtdf, there are (presumably) more optimizations >>I could take advantage of. What kind of experience do other programmers >>have with mtdf? >> >> - Dan > >Where can I find out more about mtdf? > >James One good place to look is the computer resource center -> links -> programming methods and studies -> mtd(f). Amazing how much stuff is in there. Will
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