Author: Robert Hyatt
Date: 19:30:03 03/10/00
Go up one level in this thread
On March 10, 2000 at 22:10:51, G. R. Morton wrote: >On March 10, 2000 at 17:24:18, blass uri wrote: > >>On March 10, 2000 at 16:36:09, G. R. Morton wrote: >> >>>On March 10, 2000 at 15:33:16, Mike S. wrote: >>> >>>>I have pasted the wrong FEN string, sorry. I hope it's all ok now. >>>> >>>>On March 10, 2000 at 15:28:01, Mike S. wrote: >>>> >>>>>[D]8/p1r2R2/1p1k4/7p/8/3P4/PP4K1/8 w - - >>>>>Shredder 3, on a K6-2/400 with 12 + 4 MB hash (no TB's) switches to Rf5 after >>>>>2:45, here is the log: >>>>> >>>>> 8.01 0:00.38 -0.27 2.Txc7 Kxc7 3.Kh3 Kd6 4.Kh4 Ke5 5.Kxh5 Kd4 6.Kg5 Kxd3 >>>>>7.Kh4 Kc2 (47.905) 124.4 >>>>>(...) >>>>>14.01 0:22.14 -1.62 2.Txc7 Kxc7 3.Kh3 Kd6 4.Kh4 Ke5 5.Kxh5 Kd4 6.Kg5 Kxd3 >>>>>7.Kf5 Kc2 8.b4 Kb2 9.b5 Kxa2 10.Ke5 (2.529.945) 114.2 >>>>>14.03 2:45.70 -1.61++ 2.Tf5 (15.096.562) 91.1 >>>>>14.03 3:57.63 -1.60 2.Tf5 Tc2+ 3.Kf3 Txb2 4.a3 Ta2 5.Ke4 Txa3 6.Txh5 Ta1 >>>>>(20.829.482) 87.6 >>>>> >>>>>But the evaluation is only 0.02 better so far. >>> >>>Its disappointing that shredder changes its mind only after nearly 3 minutes >>>when it is easy to see that RxR loses simply. Now I wish someone would answer >>>the question about the ?Rc8-c7 Zwischenzug . >> >>It is known that programs are weak in some endgames but Rebel won 2 endgames >>with rooks and opposite colour bishops against humans. >> >>shredder also saved a bad endgame with one pawn disadvantage against a GM in the >>Israeli league. >> >>You are right that computers are weak in very simple endgame if they are not too >>simple to be solved by tablebases but they may be strong in more complicated >>endgames when both sides have rook and bishop or rook and knight. >> >>Uri > >Years ago the explanation for the relatively poor endgame play of software was >that they did not analyze with chunk pattern recognition followed by focused >checking like humans, but rather had to waste huge amounts of effort on >worthless exponentially exploding tree branch searching with relatively few >heuristics to limit it. With very fast PCs and fast searching algorithms like >we have today this min-max tree search methodology was suppose to triumph, but >evidently not, as this very simple end game position shows. Now if there are >such simple endgames that software can?t handle efficiently, there most be even >more (and more complicated) middle game (probably closed) positions that are >really not being handled efficiently by software, positions that a great >pattern recognizer like Kasparov can grasp much quicker. Still, its hard to >believe such top programs, evaluating 10s or 100s of thousands of positions/sec, >sometimes can?t find the simple winning plan that a club player can see easily. >Something else going on? > >Best Regards Depends on your perspective. In the endgame discussed, black is winning. White has to try to find a way to draw since black has the distant passed pawn. If white trades rooks, it is easier. However, avoiding the trade has its own problems as white _still_ has to contend with the distant passer... The right answer here is probably to not play into a position where you are almost certainly lost in the first place... :)
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