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Up Topic The Rybka Lounge / Computer Chess / Transpositional possibilities?
- - By BrandonSi (***) Date 2010-03-12 17:41
Is there an easy way (web site, program, existing list, etc..) to take a given opening position, and then find all the possible transpositions / derivatives from that position?

I guess with a large enough database (maybe Mega base?) I could just set the position, then filter the entire database and see what ECO codes are found, but then I'd need to look at the initial moves for each game to determine how that ECO/opening was reached.. which could get very time consuming.

Has anyone looked into this before? Ideas?
Parent - - By Dadi Jonsson (Silver) Date 2010-03-14 10:43

> take a given opening position, and then find all the possible transpositions / derivatives from that position?


If you mean the different paths to reach the current position, then it's one of Chess Assistant's features. Here is a part of the list generated by Chess Assistant which shows the different paths to reach the Catalan. The paths are generated from the tree you are using, so you can adapt it to your needs, e.g. build a tree from a collection of games (either Aquarium and Chess Assistant can be used for that).
Parent - - By BrandonSi (***) Date 2010-03-14 13:58
Thanks Dadi, actually I'm trying to do the opposite. A rather simple example, but it illustrates the point.. If the following moves are played.. 1. e4 e5, from that given position, I'm trying to find every possible opening that can be reached and transposed into.

Like I said, that's an over-simplification, I might start 9ply in, rather than 1. e4 e5..
Parent - By Dadi Jonsson (Silver) Date 2010-03-14 17:22
I understand. This is the first time that I see this request, so I thought that perhaps you meant what I showed :)
Parent - - By Ladyhawk (*) Date 2010-03-14 17:05
Hi Dadi,

I own chessasistant 9.1.
I have looked for this feature but I couldn't find it.
How exactly can it be reached.
I want to build a tree from the games that came with my powerbook 2008.
Parent - By Dadi Jonsson (Silver) Date 2010-03-14 17:21
- - By Ladyhawk (*) Date 2010-03-13 23:41
Hi BrandonSi

Here are some ideas.

If you do a search in Mega base for a position, and the last ply leading to the position is 13 for example, then truncate all the games you have find, (also the ones with transpositions), to 13 and you will only have the moves that leading to the position.

You can truncate the games with a chess engine called Yace.  (http://www.top-5000.nl/dl.htm?file=dl/yace_pb.zip  ), unpack it and then start it up in a command window and then type :

cadiz_pgn thegamefile.pgn gamesuntill13.pgn n 13 and press ENTER

If you want to find even more transpositions you can try some program called BookBuilder.
You can dowload a demo version here http://www.downloadpipe.com/Bookbuilder-screenshot-70626.html
Start BookBuilder 4.08, go to tools and choose for delete tree. Open the menu Import and import the pgn file . Set the options for min ELO to 0. Then go to the export menu and export the book to a new rbm file, and save it to the directory where you have downloaded rbm2mvs.
To be able to convert these rbm books to pgn format we first have to convert to mvs with rbm2mvs, then to obk with fgcrwnew, and then to pgn with obk2pgn. It can be that you have to change the names because they are too long, but afterwards you can rename them again.
These programs need to be run from the command prompt, and you need 32 bit system.
If you do a google search for these programs you will find them and its freeware.
You can download fgcrwnew from http://www.vlasak.biz/download.htm
rbm2mvs is included in Pro Deo utilities witch you can dowload from http://www.top-5000.nl/prodeodos.htm
And obk2pgn you can download from http://homepages.paradise.net.nz/npattins/ChessOpeningBookPage.html

I hope this helps.

Regards Jonathan
Parent - By BrandonSi (***) Date 2010-03-13 23:47
Thanks Jonathan, I'll look into that! :)
Up Topic The Rybka Lounge / Computer Chess / Transpositional possibilities?

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