Author: Robert Hyatt
Date: 08:26:11 09/17/99
Go up one level in this thread
On September 17, 1999 at 10:54:09, Owen Lyne wrote: >Continuing to set iup my new Athlon with Crafty, tablebases, Winboard etc. So, >I'm at the EGTB stage right now. Thought people might be interested in >speed of generation - did all the 3/4 piece tablebases in about >90 minutes (Eugene quotes a PII/400 taking about 2 hours, so that >sounds about right). > >Next though is 5 piece, I have 256MB of RAM but Eugene likes >machines with 500+, so I may have a problem... > >Which bases (perhaps pwnless ones?) can I do and which are totally >impossible with the code set up as it is? Can I try anything and >just put up wirh ridiculous paging to disk and slow performance, >or is it not even possible? > >Other thought is about compression - being able to run Crafty >using compressed tablebases is absolutely awesome, and without taking >a performance hit is astonishing! Great work Bob, Eugene and Andrew Kadatch! > Take my name out of the equation... that was Eugene and friends totally... And yes, you are right, excellent code (although I hate reading some of the C++ stuff they write, just like I assume they hate reading some of my code. :) ) But it does work well, and amazingly fast... and to think that we can have all the interesting 5 piece files (just omitting 4 vs 1) in under 6 gigs is really something... >Now - how about generating tablebases, is it possible (either with current code, >or to modify code so it is) to generate tablebases where the minors >are compressed? That would be incredibly useful, especially again if it >was without much performance hit. I don't understand? _all_ the databases are compressed, but even in the uncompressed format, they are 'compressed' because of the new indexing scheme Eugene uses that takes advantage of symmetry when possible. > >It's all very well saying compressed only take 6 gigabytes (I have plenty) but >If I have to have all 22 gigabytes uncompressed while making them before I can >compress any then ouch, I don't think I can manage... I presume I could figure >out which minors are used to generate any one base and carefully compress and >uncompress accordingly, but directly using compressed minors would be ideal. > Aha... this I don't know about, but from a software engineering point of view it would seem that he should already be using compressed files while building new ones, since I would think that he uses the same probe code? Eugene?? >One step further, generate in compressed form (I know that's probably even more >ridiculous, but would hugely help those operating in limited disc space). Of >course I know the other thing someone with limited space can do is >download not generate them, but when I got 3 or 4 KB/s to Bob's FTP site >I knew that wasn't going to be any use for me... Not having to pay >the phone bill anyway... From work I get much, much faster FTP, but >via my ISP (Freeserve) and modem looks much slower (maybe time of day >was also relevant, early morning UK time much better than evening UK time >since thg latter is daytime in US). > >Owen Generating in compressed form would be a headache...
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