Author: Sune Fischer
Date: 13:22:25 04/20/03
Go up one level in this thread
On April 20, 2003 at 15:25:49, Uri Blass wrote: >On April 20, 2003 at 15:04:22, Sune Fischer wrote: > >>On April 20, 2003 at 03:23:11, Uri Blass wrote: >> >>>>>>[D]8/r7/8/5bk1/8/5B2/5RPP/6K1 b >>>>>> >>>>>>Terry >>>>> >>>>>Crafty sees this instantly: >>>>> >>>>> 4-> 0.05 2.00 1. ... Ra1+ 2. Rf1 Ra2 3. g3 Rd2 >>>>> 5 0.05 ++ 1. ... Ra1+!! >>>>> 5 0.06 0.00 1. ... Ra1+ 2. Rf1 Rxf1+ 3. Kxf1 Bh3 >>>>> 4. gxh3 Kg6 5. Kf2 >>>>> 5-> 0.07 0.00 1. ... Ra1+ 2. Rf1 Rxf1+ 3. Kxf1 Bh3 >>>>> 4. gxh3 Kg6 5. Kf2 >>>>> 6 0.08 0.00 1. ... Ra1+ 2. Rf1 Rxf1+ 3. Kxf1 Bh3 >>>>> 4. gxh3 Kg6 5. Kf2 Kg5 >>>>> 6-> 0.09 0.00 1. ... Ra1+ 2. Rf1 Rxf1+ 3. Kxf1 Bh3 >>>>> 4. gxh3 Kg6 5. Kf2 Kg5 >>>>> 7 0.24 0.01 1. ... Ra1+ 2. Rf1 Rxf1+ 3. Kxf1 Bh3 >>>>> 4. gxh3 <EGTB> >>>> >>>>Good Job! I should test all my chess software on this ending, to see if they >>>>"understand" the draw with a passed pawn or doubled pawns on the h-file with the >>>>wrong coloured Bishop. >>>> >>>>But remeber, the Mach III is slow and old, with no EGTB and solves this position >>>>quickly! >>>> >>>>Dan Spracklen had to give it some endgame understanding in the code; Which to me >>>>says what could he have come up with, had he remained creative in the world of >>>>CC? I believe he ended his chess programming career in 1994 when his last >>>>programme was for Saiteck. >>>> >>>>Terry >>> >>>I think that every programmer can teach his(her) program to have that knolwedge >>>if (s)he is interested in it. >> >>All you have to do is to support the egtbs. > >No Yes :) >You do not need to have tablebases for this and most people have not enough >memory for all the 5 piece tablebases(KBPP vs K is 5). It's a simple TB draw 4 moves in, the PV of Crafty also shows that. I believe any engine with a not completely broken TB implementation can find this draw. It might be a good position to check the implementation, though. >I do not like egtbs and they can also be counter productive >because you may be happy with a lost KR vs KPPP (Rook is more) when KR vs KPP >is drawn that unfortunately you reject because of tablebases. Getting out of bed in the morning can also be dangerous ;) If they help more often than they hurt, then I think the decision is easy. >It is possible that tablebases are productive only after you have enough >knowledge in the evaluation. I believe it is the opposite actually, the more knowledge you have the less you need the table bases. A smart engine without TBs may not declare mate in 23 but it will still win in 30 moves. >>I doubt Crafty will solve this one "on its own". >> >>-S. > >Crafty has the relevant knowledge and I do not see it as hard to solve it after >adding the relevant knowledge. > >The releavant knowledge is relevant not only for that case but also for other >cases. Maybe, maybe not (have you checked the code?). I don't think anyone is highly motivated to program lots of simple 4-5 piece specific endgames when the engine most often is used with TBs. Seems time would be better spent in the areas out of reach for the TBs. I also think there are too many exceptions to make simple rules for what is won, drawn or lost in these endgames. Often one tempi is enough to change the outcome, if you add general knowledge you are likely to be wrong in lots of cases too. -S. >Uri
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