Author: José Carlos
Date: 08:40:17 12/21/01
Go up one level in this thread
On December 21, 2001 at 11:33:48, Will Singleton wrote: >On December 21, 2001 at 09:27:01, José Carlos wrote: > >>On December 21, 2001 at 02:14:48, Will Singleton wrote: >> >>>On December 20, 2001 at 18:31:41, Dan Newman wrote: >>> >>>>>What kind of move you search first in case you don't have the move from >>>>>hashtable? >>>>> >>>>>Ren. >>>> >>>>If I'm in the PV, I do an internal iterative deepening search and use >>>>that move. If not I generate the captures, sort them with a SEE, >>>>and use the top one of those. >>>> >>>>-Dan. >>> >>>I was thinking of doing IID, and I'm not sure what you mean by the above. Do >>>you mean that if the ply 1 move is the pv move, then below that you always do >>>IID in any branch? And after the left side, you don't want to spend the effort >>>to do IID because of ... ? >>> >>>Will >> >> I can't speak for him, but I'll tell you what I do: >> I have 3 different "alphabetas": AB, AB_PV, and QSearch. In the root, I first >>call AB_PV (which implements IID). For every 1st move, AB_PV calls AB_PV. For >>the rest, it calls AB. AB allways calls AB. >> When AB_PV calls AB, and it returns a score above alpha (which is the only >>bound I pass to AB), I open the window again and call AB_PV to see if this is >>really a PV move. >> When depth=0, they both call QSearch. >> So I don't use IID in the whole left branch of the tree, but only in the "real >>PV nodes". >> The reason is to apply it only on nodes that are searched with an open window >>(BTW, I don't do any prunning in that nodes, because I expect them to be the >>PV!). For the rest of the tree, I don't need "the best move", just a "good >>enough move", that's why I don't bother to do IID there. >> >> José C. > >OK, interesting. Is the benefit significant? In my program it works fine. However, other programmers have reported no benefit at all. Worth trying anyway. José C.
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