Author: blass uri
Date: 20:30:50 11/23/98
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On November 23, 1998 at 22:38:17, Robert Hyatt wrote: >I'll play that game. we are talking about a factor of 1,000. You implied >this could easily be explained by their not doing null-move or other forward- >pruning tricks? That is your explanation? > >I'd like to suggest you break out the calculator. Null move does *not* >reduce the search by a factor of 1,000. Not by a factor of 100. Generally >not by a factor of 10. So, I re-ask... if they are only searching to 10 >plies, *why* does it take them so many nodes to get to ply=10. Want some >math? perfect tree ought to be 2*38^5 moves. They search that many nodes in >under 1 second (that is about 160M nodes). Most agree that current programs >search within a factor of two of the optimal tree size (references available >if needed). so lets say they can fully search this tree in 1 second, even >assuming imperfect ordering... Now, again, I'd like to ask the >*same* question again, and this time get a *reasonable* answer: > > > >If they take (say) 5 minutes to do a 10 ply search, at 250M+ nodes per second, >that is over 300X the number of nodes a full-width search to depth=10 should >search. If you factor in a q-search that is the same size as the full-width >part, we have a missing factor of 150 to account for. I say that is *all* >search extensions. And I say that is *far* more than any of the rest of us do >in terms of extensions. How *else* would you characterize this? I think that Junior5 also does search extension because Junior needs similiar number of nodes to do 10-11 *full* ply search. I think it can see also long lines of 30+ or even 40 plies with the extensions but Amir Ban can tell better how many plies Junior can see in the longest variations after 10-11 *full* ply search. Uri
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