Author: Vincent Diepeveen
Date: 13:10:09 05/05/04
Go up one level in this thread
On May 05, 2004 at 09:14:50, Mike Hood wrote: >On May 05, 2004 at 08:12:44, Vincent Diepeveen wrote: > >>On May 05, 2004 at 07:47:57, Mike Hood wrote: >> >>>I just let Filemon run while loading Fritz 8 to see why it takes so long. I was >>>shocked to see that during the initialisation Fritz tries to open every possible >>>tablebase. For instance... >>> >>>Open kpk.nbw.emd -- good, it's there >>>Open kpknbw.emd -- file not found >>>Open kpk_nbw.emd -- file not found >>>Open kpk_nbw_emd -- file not found (I never knew this format was valid) >>>Open kpk.nbw -- file not found >>> >>>And the same five accesses for the nbb file. >>> >>>Why carry on with the other three after finding the first tablebase? But it gets >>>even wilder when it comes to the 6-piece tablebases. All 365 possible tablebase >>>pairs in all possible formats are accessed, even though I don't have any on my >>>disk. Thousands of "file not found" results. Just one example, to show how >>>ludicrous it is: >>> >>>First Fritz tries to open krbnkp.nbw.emd, krbnkpnbw.emd, krbnkp_nbw.emd and >>>krbnkp.nbw.emd. Almost the same as before, except Fritz is assuming 6-piece >>>tablebases are compressed. But then Fritz tries to open krbnkp.0.nbw.emd, >>>krbnkp.0_nbw.emd, krbnkp.0nbw.emd and krbnkp.0_nbw_emd. Then krbnkp.1.nbw.emd, >>>etc... and krbnkp.2.nbw.emd... and all the way through to krbnkp.g.nbw.emd. That >>>means 136 disk accesses for a tablebase that I don't have! And that's only one >>>tablebase out of 365. >>> >>>Wouldn't it be much easier just to scan the tablebase directory and only open >>>the files that actually exist? >> >>Both nalimov and i do this in a similar way. >> >>If you are willing to write code for this that works faster and works both for >>windows and *nix, then i will be real happy to use it. >> >>Best Regards, >>Vincent > >Thanks for the info, Vincent. I assumed the initialization code had been written >by Chessbase, not by Eugene. > >My math was a bit off in my original post, but after looking at Filemon's log I >can give the exact figure: Fritz attempts to access 33647 non-existent tablebase >files. And please... you can't tell me that if the file krbnkp.0.nbw.emd doesn't >exist it still makes sense to look for krbnkp.1.nbw.emd, krbnkp.2.nbw.emd, etc >all the way to krbnkp.g.nbw.emd. That's a waste of processor time on any >operating system. have we found a volunteer in you to improve the code? BTW in diep i'm not using .0 .1 but use files > 2 GB in size when that would be needed (uncompressed it is), so white+black is at most 2 files of 3.6GB for 6 men, nalimov is around 17GB or so for the big ones a piece for black+white.
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