Author: Dave Gomboc
Date: 11:25:06 09/16/02
Go up one level in this thread
On September 16, 2002 at 03:45:03, martin fierz wrote: >On September 15, 2002 at 22:00:28, Dave Gomboc wrote: > >>On September 12, 2002 at 02:13:29, martin fierz wrote: >> >>>On September 11, 2002 at 23:08:19, Dave Gomboc wrote: >>> >>>>On September 11, 2002 at 16:28:37, martin fierz wrote: >>>> >>>>>On September 11, 2002 at 07:23:38, Dave Gomboc wrote: >>>>> >>>>>>On September 10, 2002 at 17:03:26, martin fierz wrote: >>>>>> >>>>>>>if you want to compare, only if you do it properly - so only if i get the >>>>>>>logfile afterwards :-) >>>>>>>and i hope you realize that even with the logfile, comparing one position is >>>>>>>rather meaningless. >>>>>> >>>>>>It's not my program, I can't make such a guarantee! But he is having a party on >>>>>>Saturday, so if I have a position I can bug him a bit to get him to log in and >>>>>>run it... >>>>>> >>>>>>Yes, I know that comparing one position is meaningless. >>>>>> >>>>>>Dave >>>>> >>>>>4-8 about 3 moves after 11-15 in the game is the real mistake. 4-8 wins the man >>>>>but loses. any normal checkers program should want to play 4-8 for a while, and >>>>>if it's good, it should switch away from 4-8 after some time. the position is >>>>>rather complicated, so you should make sure that it doesn't switch back. i've >>>>>changed a couple of things in cake after LV to make it find this faster, which >>>>>it does, but it still needs a lot of time :-( >>>>>just try glancing over schaeffer's shoulder to see when it switches to a better >>>>>move :-) >>>>> >>>>>aloha >>>>> martin >>>> >>>>Okay, I will try. :-) >>>> >>>>So are you saying that once you take the checker you're toast? Like a forced >>>>loss? Or are there drawing resources later, but it's just that taking the >>>>checker is quite a bad move? And what should it play instead of 4-8? >>>>Presumably not any move will do? >>>> >>>>Dave >>> >>>yes, there is only one move X to draw in this position AFAIK. and it's not 4-8. >>>i don't want to bias your answer so i'll just wait and see what you guys get :-) >>> >>>i have this book generator, i think there are also people in your group who do >>>this kind of stuff. i let it expand this line after las vegas, and it says 4-8 >>>is a dead loss, and X is a database draw. >>> >>>in the improved version, cake first wants to go 4-8 with a positive score, then >>>it starts getting a negative score for it, then it switches to X with a negative >>>score, and finally the negative score gets smaller. that's the reason i'd like >>>to see a search log, because from that you can see at what point it realizes >>>that winning the man is no good, and when it switches to X, and when it realizes >>>that X is probably a draw. the thing is that at first both moves look good, then >>>both look bad, and finally 4-8 looks real bad, and X only a bit bad. at least to >>>cake. so the point where a program has "solved" this position is when it >>>realizes that X is probably going to draw. not when it displays X as best move, >>>because for a long while, whether you want to play 4-8 or X is just a matter of >>>"taste", i.e. some parameters in the eval which have nothing to do with >>>understanding this position. >>> >>>aloha >>> martin >> >>Well, I couldn't run it... apparently the endgame database code is being >>rewritten at the moment. :-) >> >>Dave > >oh - too bad! i'd have been interested - i'm sure chinook would have solved this >faster than my engine, but i'd have liked to know how much faster. i've found a >problem in my evaluation which hurts in this particular position - i'll have to >try and fix it. thx for trying anyway! > >aloha > martin I will ask again when it is done. The code is being upgraded to allow the use of the 10-piece tablebases. (Not all of them are generated yet, but it can use the partial set that has been computed.) Dave
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