Author: Vincent Diepeveen
Date: 12:11:39 02/04/01
Go up one level in this thread
On February 03, 2001 at 01:52:02, Sandro Necchi wrote: >On February 02, 2001 at 21:24:43, Vincent Diepeveen wrote: > >>On February 02, 2001 at 02:14:41, Sandro Necchi wrote: >> >>So in short you prefer a 30 ply material only search >>with tactical extensions up to say 60 ply or so? > >No I meant that if you see a depht of 14/30 it does not mean 14 ply full depht >and 30 selective, but something like: >6 ply full depht up to 14 ply selective and up to 30 ply max allowed extension >search. >This means that still there is an horizon problem in some cases and only a >deeper search will let the program see deeply enough: What program are you referring to here now? Because if i show depth=14 in diep then some lines are seen up to 128 ply (usually several tactical lines reach depths like 66 or 72 ply), so that would be in reality 14/72 then, but for sure it doesn't miss anything which you mean within that depth in practical game play (of course zugzwangs in far endgame you can discuss about it needs a few ply more as normal, but that's a theoretical discussion not a practical decision). Perhaps what you mean to say is: you don't see the positional advantage from preprocessors, you find they play positional moves based upon a few ply depth instead of the depth they show? If that's your statement then i have to agree with you. >30/80 would mean (to me): > >12 ply full search up to 30 ply selective and 80 ply max allowed extended >search. Deeply enough to see what needs to be seen. >To have such a power needs a much faster computer than today's. >I do not rely on deep search as I think chess knowledge increase is better, but >sometimes only a deep search can correct incorrect evaluations/missing chess >info. A preprocessor at 30 ply is not going to answer your prays either! >I hope I was clear enough. > >Ciao > >Sandro >> >>You prefer this over a say 12 ply search of a chessprogram? >> >>>On February 01, 2001 at 09:44:28, Vincent Diepeveen wrote: >>> >>>>On February 01, 2001 at 04:11:36, Sandro Necchi wrote: >>>> >>>>>On February 01, 2001 at 03:48:09, Uri Blass wrote: >>>>> >>>>>Dear Uri, >>>>> >>>>>>On February 01, 2001 at 02:20:33, Sandro Necchi wrote: >>>>>> >>>>>> >>>>>><snipped> >>>>>>>No, maybe I did not clearly explain what I meant. I said that a friend of mine, >>>>>>>testing the program regardless of the opening book, said that it was 100 points >>>>>>>better than Fritz 6a. So it was not the book making it stronger, but the engine >>>>>>>being stronger. >>>>>> >>>>>>My impression about the engine is different. >>>>>> >>>>>>I used ahredder5 for a long time to analyze positions from my correspondence >>>>>>games when I was in theory. >>>>>>If the engine is 100 elo better than I expect it to find good moves in the >>>>>>opening without opwning book. >>>>> >>>>>I think that to expect PCs chess programs "to make theory" is wrong. The horizon >>>>>effect should create a lot of problems on this matter. it really depends on the >>>>>positions. In some program A should do better than program B and viceversa. >>>> >>>>Sorry to fall into this discussion but the word horizon effect >>>>is no longer valid. If you get a real small search depth like 6 or 8 ply >>>>then you might refer to horizon effect, but we talk about depths >>>>of like 13 ply and more here to start with knowing Uri that's the >>>>minimum depth he let the progs analyze. I'm sure Shredder at >>>>so many hours a move gets a bit more as 13 also. >>>> >>>>Horizon effect is no longer valid then, as that would mean that >>>>you assume everything is horizon effect till the game is solved by search >>>>which is quite hard on todays pc's >>> >>>No, I do not agree. Well, since the best move is selected by a numerical plus >>>compared to other moves and the programs are really selective, the depht are not >>>really valid because a lot of moves are discharged to reach such a dephts. So >>>some moves are not analized deeply enough and this would done only at high >>>dephts. >>>So to really see many moves ahead as it really needs in the early stage of a >>>game it takes a huge amount of time. >>>This situation will get better when the full search will reach 30 ply with 60 >>>ply selective. >>>I think the computer speed must be increased quite a bit to do so, so maybe in >>>the next 10 years or so. >>>I agree that a lack of knowledge would effect the search also, but generally >>>speaking in chess there are so many exceptions that needs to be analised deeper >>>to see everything clear enough to correct knowledge missing and/or wrong >>>evaluations. >>>So, my concept is the programs do not know what they know and somebody must take >>>a look to them to let them take the correct way. >>> >>>Sandro >>>> >>>>More valid is the term preprocessor + lack of knowledge. >>>> >>>>>> >>>>>>I found that shredder suggested me a stupid sacrifice and only after many hours >>>>>>the score went down and it converge to the theory move Re1. >>>>>> >>>>>>Here is the opening in my correspondence game against yoav dothan(I am white) >>>>>> >>>>>>1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxd4 a6 5.Nc3 >>>>> >>>>>Even if this is probably the best move, I think for Shredder 5. Bd3 should be >>>>>better after some moves. I know that the program evaulation is better for Nc3, >>>>>but it is important the program position understanding after some moves... >>>>> >>>>>Qc7 6.Be2 b5 7.0-0 Bb7 >>>>>> >>>>>>I gave Shredder5 to analyze this position for a long time and it needed many >>>>>>hours to avoid the bad sacrifice 8.e5 >>>>>>It changed it's mind to Re1 that is the theory move only after many hours. >>>>> >>>>>This confirms what I said before. if the position is understood by the program >>>>>the program would find the correct moves easily. >>>>>> >>>>>>I analyzed 8.Re1 when there is an interesting line 8.Re1 b4 9.Nd5. >>>>>>I can also sacrifice a pawn by 9.Na4 >>>>>> >>>>>>I did not get a clear consequence about the sacrifices and I decided after a >>>>>>long think to play 8.a3 and not to sacrifice a pawn or a knight(the game >>>>>>continued 8...Nf6 9.Qd3 d6 10.Bg5 and it is yoav to move). >>>>>> >>>>>>One of the reason that I decided not to sacrifice is the fact that my opponent >>>>>>does not have to accept and I assume in my correspondence games that my opponent >>>>>>will probably play the best move. >>>>> >>>>>Yes, you are correct. >>>>>> >>>>>>It means that if I evaluate that b4 has 50% chance to win and 50% chance to lose >>>>>>my chances are smaller than 50% because I assume that my opponent will play b4 >>>>>>with probability of more than 50% if it wins and will not play it with >>>>>>probability of more than 50% if it loses. >>>>> >>>>>I agree, but what is best to play is also what will bring you to a position >>>>>which will suite your style or positions where you can play at your top strenght >>>>>and not only a general % score. >>>>>I understand this is not easy to explain and this is why one never stops to >>>>>learn... >>>>>> >>>>>>Uri >>>>> >>>>>Sandro
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