Author: pavel
Date: 00:05:19 11/19/00
Go up one level in this thread
On November 19, 2000 at 02:49:49, Aaron Tay wrote: >On November 19, 2000 at 01:47:13, pavel wrote: > >>On November 18, 2000 at 23:40:08, Dan Homan wrote: >> >>>On November 18, 2000 at 23:23:27, Brian Richardson wrote: >>> >>>>On November 18, 2000 at 23:06:36, Dan Homan wrote: >>>> >>>>>I've just put a new version of EXchess up on my website: >>>>> >>>>>http://pc.astro.brandeis.edu/BRAG/people/dch/chess.html >>>>> >>>>>The new version (v4.01) adds Temporal Difference evaluation learning to the >>>>>previous version (v3.14). I am not sure that this really increases the strength >>>>>of the program, but it was fun to work on. There are a couple of other minor >>>>>enhancements to the search and opening book code. >>>>> >>>>> - Dan >>>> >>>>About how many games with TD learning have been played and did it change your >>>>evaluation function much? >>> >>> >>>I've played hundreds of games, but I've also reset the learned values back to >>>the original parameters many times as well. For the parameters which come with >>>the released version, I am not sure how many games contribute. Another wrinkle >>>is that the program only 'learns' after a loss, so the number of 'learning >>>games' is smaller than the number of games played. >>> >>>One consistent result is that TD learning wants a smaller value for passed >>>pawns than I was using before (about 75% of my original 'hand-tuned' value). >>>Also my knight-outpost and bishop-outpost values are consistently increased >>>by the TD learning by a factor of 3 or 4. >>> >>> - Dan > > > > >>can you elavorate TD learning? >>as far as I know, it fixes value after each game. >> >>is there any file generated by the program as a .lrn file, which increases after >>game? >>or the eval is tuned externally? >> >> >>pavs > >There is a score.par file that changes after each loss. But I don't see anyway >to combine learning from other sources much like you can import learning from >other sources for crafty's book.. > >Is there a way? Otherwise if each new version of EXchess came with a new >score.par file , does that mean the learning each user has will be tossed out? > >I'm also curious about how Exchess decides what to tune after each loss. How >does it "know" what evalution scores to change? > >I will run 100 blitz games first vers various strong opponents (to maximise >losses..:( !! ) and see how the score.par changes. Currently, i see the passed >pawn value dropping quite significantly and knight outpost values increasing >inline with what the author found.. also one more thing I noticed in the webpage, it's a brute force proram. no selective search? also it seems if the program uses losses to tune it;s eval, then it can be misinterpreted. for instance, result from a game that was played in 5 min/game, will have lesser values of importance then a game that was played at 40/40 or 40/60. so it can be interpreted that an exchess version that plays only 5min blitz will have one kind of tuned eval, while the other one that plays mainly 40/40 will differant. Which one is best? :) this are mainly assumption, as I need to know (more clearly) what TD learning is. thanks pavs.
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