Author: Vincent Diepeveen
Date: 16:14:22 04/02/04
Go up one level in this thread
On April 02, 2004 at 18:36:56, Uri Blass wrote: >On April 02, 2004 at 18:17:23, Uri Blass wrote: > >>On April 02, 2004 at 17:56:58, Robert Hyatt wrote: >> >>>On April 02, 2004 at 16:22:19, Jonas Bylund wrote: >>> >>>>Thank you very much for your detailed answers! >>>> >>>>When you say Diep already runs in windows mode, does that mean that it runs DOS >>>>or "real" windows mode? (sorry about not being clear on that in my original >>>>post) >>>> >>>>10GB for all the 3+4+5+6 tb's would be a HUGE success as would 20GB of course! >>> >>>It is also "vaporware". 3-4-5-6 tables will _not_ fit into 10 gigabytes. >> >>Yes but it is possible that tables that are enough to play 3-4-5-6 perfectly may >>fit 10 gigabytes. >> >>Suppose that you have tables that have only 1/32 of the information in the >>original 6-piece tables(it has information about exact distance to mate only if >>the index of the position is divisible by 32). >> >>You can still use them in 1/32 of the positions in case that the index of the >>position is in the table. >> >>In case that the index of the position is not divisible by 32 you can search >>forward and in order to check if the index of the position is divisble by 32 you >>do not need to look at the table. >> >>Now the question is if programs who use the smaller tables can practically play >>6-piece positions perfectly or cannot do it. >> >>Uri > >Note also that nalimov admitted that he had no time to work on more efficient >table for 6 pieces and the question is also how much can you compress the tables >thanks to symmetry. Ever thought about how many possibilities there is to just compress 1 file? Take for example a PPM algorithm that knows about how your scheme works. Compression is a science in itself, actually IMHO more complex than computerchess because you do not have infinite system time to compress real huge files (like the big 3.6GB egtb files from DIEP). Chess has a limited number of positions possible. Latest ICGA journal estimate was 10^43. I do not say there is more than 10^43 possibilities to compress a 3.6GB file optimal. >In any case win/draw information can also be productive and in second thought I >think that programs may fail in playing perfectly with only 1/32 of the >information. You could convert the nalimov's for example to a format having mate in 30, 31 .... n and everything under mate 30, so mate in 0 .. 29, you put it as 'mate'. You will figure out that you can play near perfect with that real soon. Sometimes a mate in 33 will get 34. I tried several maximin positions with diep without EGTBs and diep still mated there very near optimal. That to my own surprise. Now imagine if you have bittables available, there is 0% chance (not a perfect 0 but rounded 0) that it will *not* mate :) Of course you will figure out a theoretic situation which simply will not occur in practice. Just try it and you'll see. The chance that you will manage to escape to a 50 move rule is like 0.00000001. I just do not see it happen in reality. For a start you need to get into KNN versus KP or something. Something really spectacular and always with 2 knights involved :) Just calculate from the TBS files how many draws there are *because of the 50 move rule*. Reality is simply that not doing probes last few plies in the search is giving a factor zillion more chances for incorrect behaviour than this :) >I thought that only 1/2 of the information may be enough becase it is enough to >know positions when it is white to move so by the same logic only 1/32 may be Note it is a mystery to me where you got factor 32. Nalimov stores the hard ones in 2 bytes a position, diep stores 5 positions a byte. Factor 10 savings. All egtbs with 1 byte a position for nalimov, it is a factor 5. >enough if you search deeper but in another thought I think that it is not so >simple because the position when white to move may get index divisible by 2 but >when I go only to divisble by 4 I cannot take care that the position of mate in >x when x is even will get index that is divisible by 4. You should not be busy too theoretic. What do you want to do. Win the game, or play perfect chess? I want to win. You? You want to buy in a few years a 2 TB harddisk to store all 6 men and then you go have a try whether that's better than my 7 men? >Uri > >Uri
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