Author: Marc Bourzutschky
Date: 09:49:45 01/15/03
Go up one level in this thread
On January 15, 2003 at 11:40:29, Les Fernandez wrote: >On January 15, 2003 at 11:33:16, Marc Bourzutschky wrote: > >>On January 15, 2003 at 09:48:25, Robert Hyatt wrote: >> >><<snip>> >>>>If you are really desparate for those 5-1 endings (and like Eugene I don't see >>>>the point of generating them) you can use Johan de Koning's FEG program >>>>(available on www.chessmaster.com) to do it. For 5-1 endings you'll need about >>>>300MB of RAM and a few gig disk space. A typical pawnless ending will take >>>>about a day, an ending with pawns about 3 days, on a 2 Ghz machine. >>>> >>>>-Marc >>> >>> >>>Does it produce DTM tables that will work with Eugene's probe code? >>> >>>Or is this the win/lose/draw stuff? >> >>It has full DTM information, but stored in a quite different format from >>Eugene's, and therefore not accessible by his probe code. It should be possible >>to translate one format to the other, but such a utility does not yet exist. > >Hi Marc, > >Listen when you refer to a different format then Eugenes are you saying that in >it exists wtm draw,bwtm win, wtm mate, wtm broken, btm draw, btm win, btm mate, >btm broken info? I am just trying to understand it because perhaps I can write >a converter to go to the format I need if the info is there. Just a thought > >Les The format refers to the binary containing the actual data, and since the format is not public it would be almost impossible to write a converter yourself. During generation, the program also produces a stats file, similar to Eugene's .tbs file. The stats file contains for each DTM the number of positions with that DTM, i.e., you get complete wtm win and btm lost info (for 5-1 there clearly are no wtm lost or btm win positions). Broken positions and draws are not separated in the stats file, but it is easy enough to write a program to count broken positions, and then you can infer the number of draws by subtraction. One difference between the stats file and the .tbs file is the treatment of symmetry for pawnless endings, so you can't compare counts directly. The .tbs file restricts the two kings to 462 squares, while in the stats file it restricts one of the kings to 10 squares, so you will consistently get more positions. The compressed version of the chessmaster data actually applies full diagonal symmetery to the data, so you get even fewer positions than you get in the .tbs file, which only has a partial implementation of diagonal symmetry. But since the stats file is produced during generation rather than after compression it contains more positions. It is actually possible to collect win-loss statistics on the compressed files as well (ply by ply), which will give you the stats with fully implemented symmetries. For example, consider this wtm and mate in 2 position in KRK: [D] 8/7R/8/8/8/2K5/8/k7 w the compressed chessmaster data would only count this position once, while in the .tbs file you would get a count of 2, because it also contains the position obtained by reflecting along the a1-h8 diagonal: [D] 6R1/8/8/8/8/2K5/8/k7 w -Marc >> >>The key benefit of Johan's program is the small footprint. It only requires >>enough RAM to store the side to move, and as a result only needs about 15MB for >>6-man endings (excepting the pathological 5-1, which requires 300MB), regardless >>whether pawns are present or not. The program is also significantly faster than >>the publically available version of Eugene's tbgen program (although it seems >>Eugene has a faster version now). The complete 5-man set takes about 2 3/4 days >>to build on an AMD2600.
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