Author: Peter McKenzie
Date: 02:36:51 05/21/99
Go up one level in this thread
On May 20, 1999 at 12:48:08, Dave Gomboc wrote: >On May 20, 1999 at 06:01:29, Ed Schröder wrote: > >>>Posted by Dave Gomboc on May 20, 1999 at 03:00:12: >> >>>>Extensions (remaining): A number of the list of "Extensions on depth" >>>>is also tried in the tree. Here I use fractional increments of 1/4 ply. One >>>>idea is to push the hash table entries of best lines. In other words, if >>>>the current move is from the hash table and the move of the previous >>>>ply too then the depth is increased with 1/4 ply. Also some promotion >>>>extensions are tried which increment may vary on their importance. >>> >>>"Pushing the hash table" sounds interesting. I have never heard of this being >>>done before! >>> >>>In "Search Control Methods in Deep Blue", a small (I think 1/4 ply) extension >>>was done if a move by the opponent was made possible by the last move of the >>>opponent (i.e. they are following some plan... and might be putting together >>>some kind of combination, even if you're not sure what it is yet). They >>>referred to this as "influence", I think. I do not remember if they >>>invented it or if it was cited from somewhere else. >> >>I am not sure if I understand you correctly. Say Nf3-e1 as an example, then >>extend new possible moves like Nd3, Nf2 and so on with 1/4 ply. Correct >>interpretation? Not a bad idea. > >If Nf3-e1 was played on the last iteration, then Nd3 would get a small >extension, yes. Was Nf2 a typo? Oh, I see. In positions where Ne1-d3 was >played, yes, Nd3-f2 would get a small extension too. That's right. > >I am thinking they invented this, I haven't heard about it before either. There is an 'inverse' type idea, where you prune moves that could have been played earlier. For example, say white plays Ra1-b1, then next ply the move Rb1-c1 probably doesn't make alot of sense because it could have been played a move earlier. So you might prune Rb1-c1. Of course, this is a gross simplification but its still something to think about. Peter > >>Ed Schroder > >Dave
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