Author: leonid
Date: 15:31:21 01/26/00
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On January 26, 2000 at 13:24:21, Ed Schröder wrote: >>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 am curious to see if I understood correctly what you have said. You find for each ply all the moves and aline them in the way that the most promissing goes first. What I would like to know is if all the moves that you generate for the ply are legal. In my logic I use almost everywhere legal moves and I find all the moves for the each ply before using them. Found that very few do the same. Now I see that probably you do the same. This is why I make this question. Leonid. > >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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