Author: Graham Laight
Date: 03:56:59 07/20/00
Go up one level in this thread
On July 20, 2000 at 02:38:07, Ed Schröder wrote: >On July 19, 2000 at 18:36:28, Graham Laight wrote: > >>On July 19, 2000 at 15:02:14, Amir Ban wrote: >> >>>On July 19, 2000 at 11:06:13, Alvaro Polo wrote: >> >>>>I'll believe that adding new knowledge to Junior is almost free. I have then two >>>>questions. >>>> >>>>1.- Why isn't then Junior's evaluation much better? Please don't misunderstand >>>>me. I am sure it has a great evaluation but, one may think that when things are >>>>almost free you could just add any bit of knowledge that you might consider >>>>useful under any circumstance and have a really astounding, hypergreat, out of >>>>this world evaluation. >>>> >>> >>>Because the problem is not writing evaluation terms but deciding which one's are >>>right or formulating them correctly. Not to mention giving them correct weight. >>> >>>I don't know where many posters in this newsgroup get the idea that "knowledge" >>>in chess is obvious and it's just a matter of coding it. In fact the opposite is >>>true: the *true* and *correct* rules of evaluation ar more like a hidden mystery >>>that programmers look for like the mathematicians looked for the proof of >>>Fermat's theorem. I can easily add 20 new elements to my evaluation, but I >>>expect 19 of them will prove to be wrong, or (what amounts to the same thing), >>>badly tuned. >>> >>>The best way to become familiar with this problem is to write a chess program. >> >>I've seen programmers complain about this problem before. They also complain >>that they apply knowledge to fix a problem in one type of position, and it plays >>worse in another type of position. >> >>I've long believed that the solution is to be more systematic in the creation, >>storage, and selection of knowledge. >> >>I'm afraid I'm not going to write a chess program in the forseeable future, but >>here's my idea to store knowledge systematically, then address the problem of >>getting to the right knowledge in the right positions: >> >>* write a large number of evaluation functions (eval fn), and store them in a >>database (db) so that they can be managed and maintained (one eval fn per db >>record) >> >>* for each record, as well as the eval fn, also store some "indexes" to indicate >>the type of position where this eval fn will be useful >> >>* generate a chess position to evaluate (we're playing a game now) >> >>* compare this position with the indexes of the eval fns, creating a >>(percentage?) match value between each eval fn, and the present position >> >>* sort the eval fns into order of match value, and pick the best matching eval >>fns >> >>* apply each of the selected eval fns to the present position, weighting them >>according to their match value >> >>* do all this with some sort of "in memory" database with fast APIs, and do some >>tricks with the database indexing, so that it can all be done quickly in "real >>time" (I can post a web site of a product that can do this, if anyone is >>interested). >> >>I hope this stimulates further discussion - I personally think that this is a >>very important issue. After all - we're trying to do "Artificial Intelligence" >>here - and you can't really be intelligent without having both plenty of >>knowledge, and the ability to select the right sliver of that knowledge for the >>present circumstances. >> >>-g > >You are missing some main points which Amir explained quite well. I will >give a very simple example about one of the main problems implementing >new chess knowledge. > >Suppose you are adding new chess knowledge concerning rook moblity on open >files. It will have effect on all the other chess knowledge you have written >once before. You for instance will get unwanted side effects concerning pawn >structure, king safety etc. Unwanted negative side effects can be: a) the >engine will accept double pawns too easy because the rook wants to have >the open file b) making unsound moves regarding king safety as open rook >file is rewarded too high in respect to king safety. > >The opposite is also true for (a) and (b). Often a position requires to >accept the weakness of a double pawn, often a position requires an open >rook file above king safety. > >This is just one of the simple cases. CC is not about just coding new chess >knowledge (that is the most easy part) but how it correlates with all the >other stuff you have. And the more you have the more difficult it becomes >to add new chess knowledge because of these unwanted side effects. If you >for instance forget to check (test) chess knowledge you have programmed 5 >years ago if it still correlates with the new stuff and it doest not correlate >you end-up with a program that is weaker without realizing it (for years). > >The main problem of adding new chess knowledge is the correlation between >all the chess knowledge you have and your suggested database system will >have the same trouble. > >Ed I have to disagree STRONGLY with this assessment of my idea!!! The problem you are describing is the classic problem of "knowledge management" when you have a huge amount of knowledge. My thinking is explicitly designed to address this very issue. I'll admit right now that there is a maintenance problem with my scenario, that I quietly neglected to mention: every time you realise that you need new indexes in your knowledge db, you are going to have to "retro-fit" those indexes to all the knowledge records in the database that you already have. That's a maintenance problem which I haven't conceptually solved, yet. Even though this is "model" chess program, not a "real" one, I'd be interested to hear if anyone has any ideas about this. However, when it comes to keeping the knowledge under control, well organised, maintainable, and selected for use on just the right occasion, my idea is the tops! (imho) For every piece of knowledge, because it is in a database, you could search for it in many ways. Without losing anything in the game, you could even categorise the db records (e.g. category level 1 = pawn structure, king safety, etc, category level 2 would be a list of records pertaining to king safety, etc). If I did build this system, I would certainly include a good text description for each knowledge record in the db, and a short, concise title. Best of all, when you want to know what's happening with your eval in a particular position, you've got a ready made function which will list the knowledge records the system is going to use in the eval, ordered by their weightings! You'd also be able to see, also in order of weighting, those knowledge records that didn't quite make it into the eval. What could be better than that? Do you really believe that my ideas have nothing to contribute to the knowledge management problem? -g
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