Author: Robert Hyatt
Date: 08:39:31 06/12/02
Go up one level in this thread
On June 11, 2002 at 20:58:37, Robert Henry Durrett wrote: >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. First, the "annotate" facility in crafty _does_ follow the actual game. But as to "giving priority to the GM moves/lines" I don't know how to do that within alpha/beta. The evaluation of a program (Crafty in this case) guides the search regardless of the moves actually played in the game being examined...
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