Author: Andreas Stabel
Date: 02:16:34 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'm sorry but I don't have the time to make a program that can compare out positions, but I can make my program output all unique positions as a list of epd lines like your r4.unq file. So if you are interessted in this I can make the file and you or someone else can compare. My numbers suggest that the discrepancy betwwen our numbers lies in the way we eliminate redunant EP markers. Note that my last two columns have removed all EP markers where the EP was not legal giving a smaller number of unique positions than yours. My second column which gives the number of positions where all pawn-two-forward moves gives an EP marker is bigger than yours. Best regards Andreas Stabel
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.