Author: Andreas Stabel
Date: 03:23:01 10/03/01
Go up one level in this thread
On October 02, 2001 at 13:39:08, Dann Corbit wrote: >On October 02, 2001 at 06:04:38, Andreas Stabel wrote: > >>On October 01, 2001 at 18:21:09, Dann Corbit wrote: >> >>>On October 01, 2001 at 18:11:10, robert flesher wrote: >>> >>>>It has been calculated that the four opening moves can be made in 197,299 ways, >>>>leading to some 72,000 different positions. The approximate numbers of different >>>>games possible is 25x10 to the power of 116. a number astronomically higher that >>>>the number of atmos in the observable universe. This Quote was directly taken >>>>from Guiness book of world records 1976 edition. WOW and this is why chess is so >>>>damn hard. :) >>> >>>Unfortunately, they don't know what they are talking about. >>>There are 197,281 different ways to make the 4 opening moves. >>>There are 99,270 distinct positions at ply 4 (including e.p vulnerability). >>>The other numbers are equally suspect. >>>This has some interesting information: >>>http://www.clark.net/pub/pribut/chessfaq.html >>>Though the actual length of the longest possible game may be open to a bit of >>>debate. I have seen slightly different figures given elsewhere. >> >>My program has generated the following table - which does not seem to match >>your numbers very well. >> >>Table from opening position: >> | | Unique nodes | Unique nodes II Unique nodes | Factor | >>Ply| Total # nodes | ep = pawn two | ep = oppositeII ep = Only if | prev. | >> | | | pawn can hit II ep is legal | row | >>---+---------------+---------------+--------------II---------------+--------| >> 0 | 1 | 1 | 1 II 1 | | >> 1 | 21 | 21 | 21 II 21 | 21.00 | >> 2 | 421 | 421 | 421 II 421 | 20.05 | >> 3 | 9323 | 8023 | 5783 II 5783 | 13.74 | >> 4 | 206604 | 109262 | 77796 II 77796 | 13.45 | >> 5 | 5072213 | 1351950 | 898812 II 898812 | 11.55 | >> 6 | 124132537 | 15334851 | 10281864 II 10281862 | 11.44 | >> 7 | 3320034397 | 160373323 | 106193912 II 106193643 | 10.33 | >> 8 | 88319013353 | | II | | >> 9 | 2527849247520 | | II | | > >It appears that the only thing that does not match is the unique positions. >Here is my list of uniqe epd positions after 4 ply: >ftp://cap.connx.com/pub/chess-engines/new-approach/r4.unq.bz2 > >Perhaps you could be so kind as to compare with what you generate and tell me >where I went off. Be advised that some of the positions have "useless" e.p. >markers, but that is demanded by the PGN standard. I've checked your file a bit and it seems very wrong to me. There are positions missing like r1bqkb1r/pppppppp/2n2n2/1B6/4P3/8/PPPP1PPP/RNBQK1NR w KQkq - which you will get afte the moves 1. e4 Nc6 2. Bb5 Nf6 In addition the file contains a lot of duplicates like r1bqkbnr/1ppppppp/2n4B/p7/3P4/8/PPP1PPPP/RN1QKBNR w KQkq - r1bqkbnr/1ppppppp/2n4B/p7/3P4/8/PPP1PPPP/RN1QKBNR w KQkq a6 Best regards Andreas Stabel
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