Author: Vincent Diepeveen
Date: 14:09:23 08/05/02
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On August 05, 2002 at 16:56:41, Vincent Diepeveen wrote: I hope you realize that DIEP played hundreds of games versus knightcap at the internet, and thousands in total, and that i was a lot of these games watching. knightcap (the pc version) was a very popular opponent to beat when it was at the end of its learning curve, giving away pieces for just 2 pawns and one check. I have not seen a single testrun which managed to get to a better local maximum. *always* it was playing towards a parameter set where some parameters were at least 10 times the value it had to be. giving away pawns and pieces for just a few checks, it's real incredible. At a certain point however, knightcap dissappeared. That's too bad actually. I hope you realize that at the time when it played at the icc, that it was already completely the underdog. It usually played way higher programs. Just beating them once was already great. I remember how some crafty versions completely butchered it. these were crafty versions before bob started a major modification to the king safety. crafty's king safety was very weak, just a few yaers ago. It still is very weak, but not *comparable* to what it was a few years ago. Good work by Bob. the only few games which knightcap won was by throwing pieces into the king side of the opponent. someimtes 1 pawn for a piece in order to get a heavy piece close by. A few years ago that won sometimes a game. Do not forget that knightcap from search viewpoint had advantage over its opponents. DIEP got about 6 ply a few years ago in blitz, and knightcap already 7,8. So tactical spoken it should have seen never less than the opponent. Fact that it kept sucking says enough. Default knightcap with values which would be tuned by a decent chessprogrammer would have destroyed opponents searchin 2 ply less. At 6 ply versus 8 ply is no compare simply. In these days people used to laugh for me for designing a big evaluation, though the pro's were very busy with that too, but didn't mention it :) Best regards, vincent >On August 04, 2002 at 15:43:49, Miguel A. Ballicora wrote: > >>On August 04, 2002 at 15:24:50, Sune Fischer wrote: >> >>>On August 04, 2002 at 14:46:18, Vincent Diepeveen wrote: >>> >>>>On August 04, 2002 at 14:06:55, Sune Fischer wrote: >>>> >>>>will, believe, think, consider. >>>> >>>>Please proof it. chess is very simple compared to other >>>>applications where automatic tuning is supposed to work >>>>in the future. >>>> >>>>So far i have not seen a single decent program that >>>>can do better with automatic tuning than without. >>> >>>Well, maybe you have, do you know how the pros are tuned? >>> >>>How can it be, that the pros have such a good evaluator, while you being an >>>FM(!), can't make something better? >>> >>>>there is a shitload of freeware programs and volunteers to rewrite >>>>them to enable automatic tuning. Please >>>>pick a strong program and tune it. I would advice crafty. >>>>A small parameter set. Even big advantage for the tuners, >>>>but already a good program to start with. >>> >>>It is a non-trivial exercise to do, and I don't know every character of >>>Crafty's code. Besides I would rather spend time on implementing this in my own >>>program and get an edge :) >>> >>>I believe I can make it work, maybe even improve on it. >>>It isn't real important to me whether you believe it works or not, I think you >>>should follow your ideas and I will follow mine, actually I prefer if you forget >>>all about TDLeaf as soon as possible :) >>> >>>>Finding the best values as a human isn't trivial. It sure isn't >>>>for programs. But humans use domain knowledge your tuner doesn't. >>> >>>KnightCap was too interesting a project not to follow up on, I'm very surprized >>>it hasn't been done already. >>>To see people write that it doesn't work when a) KnightCap proved it _did_ work, >>>and 2) they have not even attempted it themselfs, is very funny to me. >>> >>>-S. >> >>5000 parameters is not much when compared to the parameters needed to obtain the >>optimal conformation of a protein with a computer. In that case, it is almost >>impossible (with the current knowledge) to obtain the right conformation >>starting from scratch, but is is very doable when you start from the "optimal" >>conformation (determine by physical methods, not by a computer), you change >>something and see how the new conformation would look like. Iterations around >>the minimum are very fast because all the parameters behave almost linearly or >>close enough. When the parameters behave linearly the time to resolve the >>problem is O(1) (a linear regresion of n parameters is O(1)). So, even if they >>are not perfectly linear, it is way below n log(n). This might not be exactly >>like chess but it allows me to make this guess: I believe that learning methods >>will be useful to tune all the parameters when a new one has been introduced. >>I wonder how many parameters has been throw out in good programs just because >>they did not work, but they just needed a general fine tuning of all the rest. >> >>Regards, >>Miguel > >For the experiments i conducted it didn't parameterize of course all >parameters, but i focussed upon a few important parameters. > >The ones which are tunable from the GUI too. that's about 50 parameters >in total. > >Of course there are 3 start values > - a) default values > - b) random values > - c) all values random > >What we see in case b and c is such horrors that i don't want to discuss >even about it, but in case of a we see that the newlocal maxima it choses >never gets even *near* to the local maxima of the default values. > >I know many who tried TD learning and i only had to look to how >knightcap played and to see some writings about what the guy did, >to realize what it was doing. > >The results of knightcap (as interpreted by me), >tao, zchess, DIEP, the king and ZZZZZZ and >many others are all similar what learning is doing. > >You toy for a long while and think: "perhaps do it different". > >If i design a pattern p, then obviously i have in mind it to be positive >or negative. In short a bonus or a penalty. Nothing as important as the >+ and - sign. > >this is the most important mistake one can make: the + and - sign of a >heuristic. > >Secondly there is the fine tning of the heuristic. > >obviously when a heuristic is +2.000 it doesn't matter whether a tuner >tunes it as +1.852 or +2.425 > >However when it gets +5.0 then obviously something is WRONG. dead wrong. > >If a passer bonus which always is positive gets from +1.0 to -0.75, then >we talk about a major problem. > >But the real problem is the lack of domain dependant knowledge. Where >each pattern has been typed in by hand, obviously it's a waste of time to >use automatic tuning. > >If i speak for diep i wouldn't know how many parameters i have. It's not >important. we talk about tens of thousands probably. It's been years that >i counted. > >Look it's very easy to get bunches of parameters by using arrays to index >a heuristic. > >Where many pro's don't use arrays but a constant value, versus me perhaps >an array, that's directly a factor 64 difference in the number of >'adjustable parameters'. > >I even try to avoid arrays a little, in order to get not a too huge >program. It's already not fitting in any PC's L2 cache which ain't >funny, though not a big problem (not all parameters get considered >each evaluation, you get a kind of logarithmic behaviour in selecting >of course which patterns to evaluate so the price of extra parameters >is not there simply). > >Obviously automatic tuning is only useful if it manages to create better >local maxima when it runs longer. > >Does it with your protein research?
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