Author: Ricardo Gibert
Date: 06:48:15 09/01/99
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On August 31, 1999 at 22:01:49, Robert Hyatt wrote: >On August 31, 1999 at 15:47:54, Ricardo Gibert wrote: > >>You've missed the point. You're focusing to much on the specific examples and >>missing the generalization. Everybody realizes more than one bishop of the same >>color is rare. That is a feature the is incidental to my point. I used these >>examples to save myself work of producing less trivial examples. Do you really >>believe there do not exist analogous examples that are more practical bent? You >>focus on the tree and overlook the forest! >> > >Personally, I like trees better. :) > >But in any case, the bishop + RP is a special case that I handle. There >are many others. My approach has been to fix the special cases that hurt, >and ignore the ones that don't... IE I saw crafty get tricked into many >RP + wrong bishop endings. Now I don't get tricked. > >And btw, I saw genius vs crafty yesterday, where genius out of the >clear blue sacrificed a bishop leaving crafty with a bishop + wrong >rook pawn. Unfortunately for genius, crafty announced a mate in 26. >Because it was _not_ a draw. That is what being too 'general' will get >for you... I don't call 'em a draw unless I am _sure_ they are draws. >And I don't lose games in this insane say. :) Yes, that was being too general, but the point of my post was not about "same color bishops". I was pointing out 2 things: 1) "Advantages" are not additive. Sometimes they an advantage is meaningless even when it is a whole piece. 2) An eval of highly similar positions can produce wildly different results. In the 1st & 3rd case, a 2nd bishop of the same color makes no difference, but in the 2nd case gave an easy win. The examples were meant as an illustration of what I believe is common. Determining whether an "advantage" is significant is part of the reason for performing a search, but it may take too long and a program will miss what is very obvious to a human using a non-search non-heuristic method, i.e. logic (actually a diferent kind of search). > >But for every special case I see, I fix. IE Crafty _NEVER_ gets burned >by playing Bxa7 and letting black play b6 trapping the bishop. And I can't >count the number of games it has won by using this code to not protect that RP >knowing that the opponent won't take it. And when they do... > >So special cases are not bad, because I don't believe there are an infinite >number of those that are significant. And for every one that is found and >included, that is one less way to screw up... > >One of the most common examples is _always_ two bishops of the same color. >Which is interesting. But which will never happen in a real game. So it is >interesting from a theoretical point of view, but not from a practical one. >And I'm more interested in solving practical issues that hurt crafty or help >crafty in real games...
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