Author: Ed Schröder
Date: 10:24:21 01/26/00
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>Posted by Peter W. Gillgasch on January 26, 2000 at 09:18:55: > >In Reply to: Re: DB NPS (anyone know the position used)? posted by Ed >Schröder on January 26, 2000 at 03:07:42: > >On January 26, 2000 at 03:07:42, Ed Schröder wrote: > >>On January 25, 2000 at 23:57:33, Ernst A. Heinz wrote: >> >>>> In a one by one setting it does not matter at all. >>> >>>Still not convinced: a quiescence node that produces a direct >>>"stand pat" cutoff obviously generates less work than one >>>which fails to do so -- even in hardware! *** QED *** >>> >>>Or am I missing something? >>> >>>=Ernst= >> >>Something else... I always wondered about this free 4-ply evaluation. I >>can understand that evaluation for the current position done in hardware >>is possible in a few cycles. I can't understand this also to be true for >>4 plies as it should involve: search, hash table, q-search etc. In other >>words a complete chess program. > >Well of course they have a complete chess program for interior nodes >in hardware as you know. The idea why I think that the position does >probably not matter too much is because something like 0.07 percent >of the nodes they do are calculated on the SP and the remaining >99.93 percent of the nodes are done on the hardware where the transition >from father to sibling and back has a fixed cost regardless of move >ordering. I am not saying that the size of the tree is not influenced >by the position, I am also not saying that the time it takes to complete >a 4 ply search on the chips does not depend on the position. > >You have experience with one by one move generators since your ARM >program did that. What is your gut feeling, assuming that all moves >spend the same time in MakeMove/UnmakeMove (hypothetical) and all >your move generators need the same time to produce the next move >(only a little hypothetical) and you have no instruction count >differences between the usual case versus the "get out of check" case, >would you see any major NPS differences between different positions ? I think you mixed me up with somebody else. I always do and have done a full move generation and then sort the move list first based on a fast static evaluation. I have tried the one by one approach but it was not superior. I suspect the reason is Rebel's expensive evaluation function. If you have a fast eval NPS will drop considerable doing a full move generation plus a quick-sort. Having a slow eval like Rebel you hardly see the NPS drop and you can afford such time consuming things. Ed >For me it is pretty much constant, ups and downs by maybe 1/6 which >I attribute to the varying execution times of MakeMove/UnmakeMove and >the differences between "in check" and "not in check" nodes. > >-- Peter
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