Author: Bas Hamstra
Date: 01:49:15 09/16/99
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On September 15, 1999 at 19:42:34, Andrew Williams wrote: >On September 15, 1999 at 17:12:16, Dan Homan wrote: > >>I was reading the crafty source again the other day and noticed that >>Bob has a special function to improve the move ordering at the root >>of the search. >> >>I really didn't feel like writing such a function last night, but I >>thought instead to use the values returned by the search itself to >>improve the move ordering at the root. I know that I only get an >>accurate value for the best move, but I thought that my fail-soft >>search might return useful numbers for the other moves as well.... >> >>Implementing this was pretty quick and easy: there were a couple >>of pit falls, but the total changes were about 5 lines of code. >>Previously I simply used the same move ordering at the root that I >>use at all other nodes. >> >>The improvement was amazing! I got a full ply in many positions and >>about a half-ply in many more. It improved my solution times on WAC >>noticably and seems even better in quiet positions. >> >>I know that my solution was a quick kludge, so I am wondering what >>other people do for move ordering at the root of the search. >> >> - Dan > >Hi Dan, > >This is what I used to do. (I'm also using fail-soft). It's one of those >things that shouldn't really work, but seems to do very well. However, >I later changed it to use the number of nodes in the sub-tree to order >root moves. If I recall, this made very little difference to my program's >performance; I just prefer this, because I know why it should work. Interesting. Isn't this in fact the same discussion as a few days ago? Using values < Alpha for movesorting? In this case on the root. Well, if it shouldn't work, why does it, if it does, if you know what I mean? And if it works, I would very much like to hear Bob's reaction. Anyway I will try this too. Regards, Bas Hamstra.
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