Author: Russell Reagan
Date: 19:47:05 12/28/03
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On December 28, 2003 at 20:54:36, Bob Durrett wrote: >On December 28, 2003 at 13:32:05, Tom Likens wrote: > >>Hello Everyone, >> >>I've been experimenting recently with using the evaluation function to shape >>the search tree. Specifically, I've been using the static evaluation of >>the current position and the previous position to determine if a move should >>be extended or reduced. I also have been making allowances for moves that >>increase or decrease the pressure against the king, attack hung pieces, >>save hung pieces etc. >> >>So far the results have been exciting, but also potentially frustrating. >>The main problem I've encountered is that any pruning or extensions based on >>the previous node's score cause hashing problems because this becomes path >>dependent. In a way, I suppose this isn't much different then making these >>type of decisions based on the value of alpha or beta as well, but these new >>effects have (at least for my program) seemed more detrimental. >> >>My (obvious) question, how do other programmers deal with this phenomenon? >>I suppose ignoring it is one option, but I'm hoping there is a better >>solution. >> >>regards, >>--tom > >Your bulletin is exciting since it shows there is still room for innovation in >engine design. As you and others here develop and implement this idea the >overall level of play of chess engines will go up simply because the >front-runners will be forced to adopt some of your new ideas. I have often had >the suspicion that "current wisdom" regarding searching, pruning, and the like >is holding back the truly innovative people who might feel obligated to cling to >the old ideas. I think the whole current theory about "extending and reducing" >needs to be re-thought, although I am definitely no authority on that subject. >The Earth is not flat after all! > >Perhaps the next extension of your idea is to perform and utilize complete >dynamic position evaluations to refine the searching. > >Congratulations to you and the others for corageously pursuing a new idea which >perhaps may go against "current wisdom." It is only through original innovation >and invention that advances will be made. Old ideas are not always the best >ideas. > >Bob D. I don't think anyone's creativity or passion to find new ideas is hindered. It is just hard to find new ideas that are significant improvements, and even then I bet many people do not publish their ideas that work. I know for a fact that some people already use this idea of guiding the search by the differences in evaluation between plies. The fact is that we really have no idea what the top engines do, and the top engines may already use these kinds of ideas, and many more that aren't publicly well known (obviously they do since they are significantly better than a lot of engines that use all of the well known ideas). It might not force the top engines to add these new ideas. Another thing to consider is that a good engine has ideas that complement each other well. An idea that significantly helps one engine might not help another one at all.
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