Author: Mridul Muralidharan
Date: 12:42:54 03/18/04
Go up one level in this thread
On March 17, 2004 at 18:40:05, Sune Fischer wrote: >On March 17, 2004 at 18:16:11, Mridul Muralidharan wrote: > >>>> Take a set of quiet positions and it will be possible to see history being >>>>totally equal or slightly worse or slightly better than random (or no) move >>>>ordering. >>> >>>I don't think so, random is about as bad as you can get. >>> >>>History tables, while they may not be perfect, are certainly an improvement upon >>>randomness. >> >>Maybe I forgot to add YMMV :) >> >>But my expiriments on crafty have lead me to believe that crafty can do better >>than history. > >Well, that goes without saying because one can _always_ do better! :) > I meant better than using history :) >>Ofcourse , for me , history totally sucks - no doubt about it. >> >>History is damn cheap (well almost :) ) , and almost all sites on chess >>programming have it mentioned ;) so anyone starting off would think it is like a >>gospel truths that history performs well. >> >>The amount of attention that it gets and the amount of chess programs that it >>has made its way into is dispropotionate to the benifit it gives :) > >They are easy to explain and easy to implement, perhaps that's a factor. > Very true .. but how many actually get the idea behind history ? Few I think ... If you understand the philosophy behind an idea , you can tweak and play around with it. >>If people expiriment more (and more often too !) , then you may come up with >>other schemes that are far better. > >Of course. >HH is only the last resort but every bit needs tweaking :) > Yes , even if you do use history , there are loads of improvement over the bland history[from][to] style .... >>I dont use history or pcsq or any crude piece/from-to based move ordering >>schemes anymore - gave them up about 6 months or so after starting seriously. >>I still keep revisiting them , tweaking them , etc due the obvious "cheapness" >>in these schemes - IF i can get a good solution - then why not use it ! ;) >>But of all the initial attempts , I found history totally bad and nothing has >>changed my opinion about this till date. > >I agree there are far better ways, most of them more expensive too. > >I don't see any reason to call them "totally bad" though (not unless you intend >to mock those that use them ;) as they clearly are better than doing >nothing. Hmm , I think I should have put a ":)" after that statement - just so that you did not come to the conclusion that I am mocking you (or others) ! It was definitely not my intention. But anyway , I could never have possibly mocked for example , you and Gerd ! Both of you use some techniques on history that I had not seriously expirimented with ! (Which sadly still did not work well for me , when I tried them yesterday and have a roughly 15 - 20% hit as compared to my current move ordering scheme : inspite of the speed boost (time to solution and nodes searched - both worse) ). >YMWV. (your milage _will_ vary) > They did vary :) >>(Even the very interesting study by someone a few months (?) back on various >>move ordering heuretics was not really convincing since I did the same and found >>contrary results .... maybe mine of his code had bugs ;) ) >> >>Maybe in initial years of computer chess when processing power was very very >>pricy then history might have had some kind of benifit (whenever with luck it >>does not deteriorate into randomness ...) but harping about same ideas 10 - 25 >>years later still does not smack well of progressive and scientific thinking >>.... >>Today , you can definitely attempt better schemes - a 50 knps drop if it leads >>to 20 % smaller tree is an amazing gain today - while such a propotionate speed >>drop when programs were barely doing 6 - 8 ply was unthinkable earlier on ! >>(reasons for this should be obvious ...) >> >>Ok , enough rambling , 3:30 at night can do crazy things to brain :( > >Your clock must be broken, mine is showing 00:34 am. :) We have only 2 - 2:30 hours gap ? Cool ! where are you located ? Best Regards Mridul > >>Good night , Best Regards and have a "happy history" ;) > >Alright, nighty night then. > >-S. >>Mridul
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