Author: Robert Henry Durrett
Date: 17:58:37 06/11/02
Go up one level in this thread
On June 11, 2002 at 18:01:40, Robert Hyatt wrote: >On June 11, 2002 at 15:56:19, J. Wesley Cleveland wrote: > >>On June 11, 2002 at 11:52:47, Robert Hyatt wrote: >> >>>On June 10, 2002 at 18:45:03, Dieter Buerssner wrote: >>> >>>>I'd like to add, that not for all engines, it is some sort of luck, when they >>>>remember past analysis, and when not. I am convinced, that for my engine, it is >>>>better in general, to analyze from back to front. I am also convinced, that it >>>>will not forget previous analysis. >>>> >>>>Regards, >>>>Dieter >>> >>> >>>It _must_ unless you have a hash table of infinite size... >> >>If crafty stored the result returned from the prior search in the hash table, >>made the age current when the hash table returns a valid score, and started ply >>1 with the move in the game, it would always get the most useful value and >>nearly always get the very useful values. > >Crafty does this. Unfortunately _this_ search can overwrite the results from >the previous search quite easily. And then you have a problem. Or, in lots of >cases, just because the position after the move played at move 29 is found to >be bad, when you back up to move 28, you find that the opponent can play a >_different_ move at 29 and not wreck the score so you still don't see the >"problem" since you didn't search down _both_ paths, just the path actually >played in the game. > >in short, searching from the back to the front leaves huge holes in the tree >you pretend to be searching. > >As I said, I tried this when I first started doing the "annotate" command >in Crafty (which was several years ago) because it seemed to be an obvious >idea. But after lots of testing with many different people, it became apparent >that it caused more questions than it solved problems... > >At least the current version is consistent in how it behaves, which (for a >computer program) is a good thing... Why not find some sort of compromise? Here's why you might want to: So far, GM games between the very top human GMs simply produce moves and lines which are better than those produced by current chess engines. [I believe this to be true.] As long as this remains the case, then it seems prudent to take the human GM's moves and lines into account, and give consideration of these higher priority in searches. In other words, if asking the chess engine to do a post-mortem ["overnight"] analysis of such a game, you would want to closely examine the human GM ideas expressed in that game. Bob D.
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