Author: Vincent Diepeveen
Date: 08:21:35 01/29/00
Go up one level in this thread
On January 29, 2000 at 03:08:33, Christophe Theron wrote: >On January 29, 2000 at 01:52:32, Vincent Diepeveen wrote: > >>On January 29, 2000 at 00:47:58, Christophe Theron wrote: >> >>>On January 28, 2000 at 13:19:20, blass uri wrote: >>> >>>>On January 28, 2000 at 12:31:29, Shep wrote: >>>> >>>>>On January 28, 2000 at 11:31:29, Amir Ban wrote: >>>>> >>>>>>On January 28, 2000 at 05:25:26, Shep wrote: >>>>>> >>>>>>>On January 27, 2000 at 10:40:05, Jari Huikari wrote: >>>>>>> >>>>>>>>Where you consider the position of a game changes to middle game / end game? >>>>>>>> >>>>>>>>opening == most pieces haven't moved yet ? / opening book not ended yet ? >>>>>>>>end game == few pieces left ? >>>>>>>>middle game == neither of the two above ? >>>>>>> >>>>>>>I suppose some programs have a more fine-grained approach to this. >>>>>>>Tiger for example divides the game into several "phases" (more than 3 for sure >>>>>>>:) according to the material on the board, and different evals >>>>>>>(/extensions/pruning/...?) are fired off according to the phase the program is >>>>>>>in. >>>>>>>In the DOS version, it would show "Phase x/y"; in Rebel Tiger, the best way to >>>>>>>see it is when the eval suddenly jumps from like "+1.10" to "+0.20" (or vice >>>>>>>versa) after a capture has occurred. (Contrary to Fritz, this is _not_ due to >>>>>>>any preprocessor oddities. :) >>>>>>> >>>>>> >>>>>>Why isn't it like Fritz ? It sounds exactly the same. >>>>> >>>>>It does not happen to Tiger that he says "+0.00" and then after the next >>>>>capture, shows "-3.00" immediately. That would be a result that has been >>>>>reported repeatedly about Fritz. Tiger's eval may go up or down a bit, but it >>>>>does not miss losing moves just because it was "in the wrong phase". >>>>>So I suppose there's a difference between the preprocessing Fritz employs and >>>>>the things Tiger does between phases. >>>>> >>>>>Of course I cannot point the finger to it, not knowing either program's source >>>>>code, but I figure that Tiger's approach is different (besides, such drastic >>>>>eval changes (1 pawn or more) are _extremely_ rare for Tiger). >>>> >>>> >>>>I do not understand. >>>> >>>>Do you mean to say that the only difference between tiger and fritz is in the >>>>size of the change in the evaluation? >>>> >>>>Can tiger show scores of +0.4,+0.5,+0.5 +0.46 and never showing +0.9 and after >>>>the expected moves scores of +0.9,+0.95,+0.93,+0.96? >>>> >>>>If it can than I see no difference between tiger and fritz (except the size of >>>>the change) >>>> >>>>It is possible that you meant that tiger can show something like >>>> >>>>depth 7 +0.4 >>>>depth 8 +0.5 >>>>depth 9 +0.5 >>>>depth 10-13 +0.9 >>>> >>>>and after the expected move >>>>it can show from depth 1 to depth 10 evaluations of +0.9? >>>> >>>>If this is the case than tiger is not a root processor but can have jumps in the >>>>evaluation because of being a processor of something that is not the root but >>>>close to the root. >>>> >>>>Uri >>> >>> >>>You cannot use this to judge if a program is a root processor or not. >> >>>The score of a deep line can be stored in the hash table, and once it is found >>>in one search (maybe after a very long time), it can be found immediately in the >>>next search because of HT persistency. >>> >> >>the score changes for some part sure can be from hashtable, but not in >>this drastic way Christophe! >> >>This is like Ed saying he doesn't use the nullmove idea! >>You can change the type of car, but it remains a car! > > > >Ed does not use null move. > >You want his sources to check, maybe? > > > > >>Tiger is obviously suffering from the fritz effect, after >>queen gets off suddenly score changes drastically. For example against DIEP >>in dutch open diep was at -1.0, tiger at +1.0. Tiger offers queen exchange. >>Diep wasn't expecting that and would not have done it in the same way. >>Diep happily exchanges and goes to very close to zero, before >>capturing it already goes to a score X which is near to zero. >>After physically moving the queen and exchanging it, my score doesn't >>change much, though hashtable is quite some bigger and having more probes. >>Score difference is 0.00 usually when relatively seen (11 ply X score >>goes to after making 2 plies at board to about X score at 9 ply). Tiger >>dropped nearly a pawn DIRECTLY at very small depths already after diep >>took the queen. That is not a hashtable issue! >> >>Tiger changes incredible much. doesn't take away that you can evaluate >>a lot of other things in positions, but preprocessor obviously is very >>important to Tiger's root score! >> >>I saw at dutch open that tiger uses a kind of gnuchess stage (0..9) >>to express where it was, and it putted that in the root to the screen. >>I don't understand why you print out a GNUchess stage at the >>root Christophe at the screen! For a preprocessor it is needed though. > > > >Tiger uses different algorithms for each stage of the game. > >That means my search, pruning, extensions set and knowledge set are different in >every stage of the game. This means obviously you change things in the root instead of the leafs, so that makes tiger a preprocessor. >I display this on the screen in order to amuse the kids that pretend to know >everything. >And it works. ;) > > > > Christophe
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