Author: Dave Gomboc
Date: 11:25:38 05/19/99
Go up one level in this thread
On May 19, 1999 at 08:05:28, Mark Young wrote: >On May 19, 1999 at 02:55:48, Dave Gomboc wrote: > >>On May 18, 1999 at 22:52:23, Mark Young wrote: >> >>>On May 18, 1999 at 22:18:47, Dave Gomboc wrote: >>> >>>>Some balance here is necessary. Some people are content to say that if a move >>>>is selected as best, this is good enough. Other people insist on seeing a score >>>>accompanying the move that accurately reflects the theoretical value of the >>>>position after the move is played. >>>> >>>>It is important that an accompanying score is accurate. This certifies that the >>>>software has seen its way through whatever complications may be present. >>>>Changes to the position that do not interfere with the themes that support the >>>>main line of play will not prevent a solution from being found. >>>> >>>>It is important that the best move is played, even if the accompanying score is >>>>not accurate. This certifies that the software understands enough about the >>>>position to make its way forward correctly -- for the moment. It is useful to >>>>identify that a move is likely to be the most promising, even if a definitive >>>>conclusion has not been reached. >>>> >>>>It is fair to say that the while the former is better, the latter is often >>>>adequate. If the software's assessment of a position is highly perturbed by >>>>"small" (read: irrelevant) changes to a position, then it could be said that >>>>much "luck" is involved in it choosing a particular move or another. More >>>>often, though, assessments do not vary widely between positions with "small" >>>>(again read: irrelevant) changes, and in this case, it is partially the >>>>consistency of the assessing that allows the proper move to frequently be >>>>chosen, even without the discovery of a tactical verification, or tactical >>>>refutation of alternatives. >>>> >>>>So, in testing, prefer a proper score, but do not ignore a proper best move >>>>without a proper score. It is still doing something right: give it half credit. >>> >>>What is the proper score, any + score, a huge +score....the only proper score of >>>a winning positions is mate in n. >>>> >>>>Dave >> >>This is a valid question. I think that a "proper score" is one that is high >>enough relative to the alternative scores that a certain path is absolutely >>guaranteed to be selected (including from perturbations of the position to be >>played from.) This is different from the usual notions of "seeing that it can >>win the piece", et cetera: a sufficient, but not necessary criteria for matching >>my "good enough" score. >> >>If the scores for all of the moves but the best one are abysmal, then it has >>found that only one move is playable, even if you don't see that it wins (or is >>actually not good enough anyway!, but is still the best move because it holds >>off a resignable position as long as possible.) If the scores for four or five >>moves are roughly even, this isn't really good enough to score "full points" >>IMO. >> >>We can see that if the program reaches a position that it presumed to be okay >>(in an earlier search), but sees that it is resignable when it gets there, it's >>toast. Finding a "proper" score at some earlier stage would have allowed it to >>avoid the error completely by not playing to the bad line. The major idea >>behind singular extensions is to see what is happening at the "end of the >>tunnel": you can see those fail-highs and fail-lows early enough that you can do >>something about them (head towards the position, or avoid it.) Programs that >>see "proper scores" from further back in the game are going to be stronger than >>those that don't, ceteris paribus. > >So what you are saying is the program has to see it tacticly, or it does not >count. Programs have other aspects to them then just there search, and I see >nothing wrong with a program finding the correct move by seeing the other line >get killed, instead of seeing this one move wins. This is something that I definately did not say. At least, I tried to be very careful not to. In some positions with some chess engines, even a steady one-third of a pawn difference might be enough to make such a guarantee. The margin of difference required depends on the position and on the engine. >You did not really answer the question, and we are back at square one. All of >what you are saying is subjective thus anyone can reject any BM played by any >program producing almost any score. You are trying to split the baby and I don't >think it can be done. > >You need to show me how this is workable with some examples. I am not about to enter a comprehensive scientific experiment to do so, sorry. >>Dave Dave
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