Author: Robert Hyatt
Date: 19:58:20 09/15/99
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On September 15, 1999 at 22:47:53, James Robertson wrote: >On September 15, 1999 at 22:37:34, Will Singleton 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 >> >>I find it odd that you'd get an improvement with that scheme -- what were you >>using before? >> >>I now use the node-count method, which worked better than my previous method, >>which I don't remember right now (might have been your new one). >> >>Will > >I don't use any root-ordering method. How much does it help you? A full ply or >even half a ply or even a quarter of a ply would be wonderful. > >James I assume that at least you were searching the best move from the previous ply _first_ before trying any others? If not then better ordering would be a huge gain. But if you did that, it shouldn't be significant except for some tactical type positions... where it continuously changes its mind at the root..
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