Author: Aaron Tay
Date: 02:04:05 11/19/00
Go up one level in this thread
On November 19, 2000 at 03:05:19, pavel wrote: >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? LOL becuase of this statement on the website? " Brute force searches to 60 ply (1 ply = a move by one side). Recursive null move pruning. " You don't really think Exchess routinely does brute force to 60 ply do you? I think that's just a maximum ply.. Besides the web site talks about "recursive null move pruning"..Even someone like me know that once you see the word " pruning" and probably null move , we can't be talking about pure brute force..So my guess is yes, Exchess does have "selective search"... Correct me if I'm wrong, but this "selective search" vers "Brute force" is not a major issue these days.. No modern day programs are 100% brute force these days..Every program does "selective search"... Of course how selective the search should be and how much risk each program takes in pruning each line is a matter of taste.. I;m just waiting for someone else to say old paradigm= brute force and new paradigm = selective search or as someone already done that? I think if people are going to walk around and throw around terms like "Selective search" , "brute force" , " New paradigm" they do well to read up on it first.. > >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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