Author: Robert Hyatt
Date: 06:37:35 02/24/98
Go up one level in this thread
On February 24, 1998 at 09:34:46, Robert Hyatt wrote: >On February 24, 1998 at 06:24:04, Thorsten Czub wrote: > >>I thought fritz/nimzo vs. Rebel are an exception ! :-) >>From my point of view there is NO pattern in the games - rebel8/9 looked >>pretty outsearched ! And this means you don't get a typical pattern like >>: >>your king safety is too weak or enemy handles the pawns better or >>whatever. >> >>Concerning the hash-tables I have to admit that fritz seems to handle >>them different than other programs. fritz is very hash-table sensitive. >>I don't think other programs behave the same way concerning hash like >>fritz does. >>Maybe Frans has programmed something different. >>You can test yourself by reducing hash-tables in fritz5 and find out >>THAT fritz is very sensible if you reduce the hash. >> >>no - the fast searchers have - for the first time in the history of >>computerchess and ssdf-list, overtaken the knowledged based programs. >>THATS the big surprise. > > >you haven't been around long enough to say that. Can you spell Chess >4.x? >they went from smart/selective to dumb/fast, and set the world on fire. >Cray Blitz went from smart/selective to dumb/fast (at first) and went >way >up in speed, with a real rating of 2258 (USCF) in 1980. There's nothing >new here at all. You simply find that there are two approaches. Fast >means simple, which translates into easy debugging issues. Smart means >complex, which translates into complex debugging issues. Although I >don't >agree that Rebel is a slow/smart program when it is faster than Crafty >on >equal hardware... > > > >>When we played in Paderborn we had many discussions concerning >>OUTSEARCHING the opponent, due to the fact that ChessTiger and Nimzo98 >>behaved like this. >>Nimzo98 outputs did not show this but the games looked like this. Any >>opponent of ChessTiger was starring with wide eyes on it's search >>depths. Vincent ran arround and told anybody stories about SCHACH3.0. In >>the game vs. clever+smart e.g. this was very easy to see. Clever got a >>fail-high, and after 2 minutes a bad fail-low following Tigers moves. >>Nimzo98 attacked Tiger like hell, the game turned arround several times. >>But - in the end was also a draw. >> >>Maybe Fritz5 with big hash can OUTSEARCH the others, meanwhile fritz5 >>with LESS hash cannot do this. >>I have tried it out myself by putting enough ram into my machine. The >>changes were drastic. WHY ? > > >If I were Frans I'd be concerned that my hash-replacement algorithm was >*not* doing its job. IE in normal positions, we only get 10-20% hash >hits >anyway. So there's no reason to go in the dumper when the table fills >up, >*unless* the hash replacement algorithm is not working well, or is too >simple >to work well.. > > >>WHat is Frans doing with the hash-tables ?Or better - what is he doing >>different that increasing of hash lets the playing-strength increase >>linear ! >>One main thing of course is the big number of HITS fritz gets with >>computing almost 200K NPS. > >but it isn't that big. IE Cray Blitz, searching 5-10M nodes per second >reports 20-30% hash hits (max) in the opening/middlegame. It does go >*way* >up in endings of course... there is another idea I just thought of. Suppose Fritz is very sloppy in move ordering (IE it doesn't try the history heuristic, to avoid the extra instructions needed). In that case, it might be *very* dependent on getting a transposition/refutation table hit to suggest the best move to try. This would be *very* ugly, but it is possible...
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