TalkChess.com

[ed]

After intensive research I finally found an successful way to improve the playing strength of Pro Deo using a chess tree. Since the format of the chess tree (called: EOC) is an open source every chess programmer can add the algorithm to his/her own engine and gain some elo points without too much of a hassle.

Download and explanations: http://www.top-5000.nl/prodeo.htm

How to make and access EOC: http://www.top-5000.nl/eoc.htm

Technical issues:

1) The EOC source code doesn't contain the Pro Deo formula used to calculate the bonus/penalty for each move found in the EOC chess tree, if there is interest I would happy to provide it.

2) New in Pro Deo 1.5 is also the option the automatically update the EOC chess tree while playing its games, it seems to help too. It's controlled by the following parameter in a personality.

[EOC Learner = on] * off|on

On request I can provide the source code of this routine too.

Observations.......

The last months I have tried several EOC databases, using it as an opening book gave terrible results, using a giant 100 million positions (!!) chess tree (unfortunately) was unsuccessful too.

Then I made an EOC from about 120,000 quality comp-comp games between the 20 best chess engines, added about 30,000 human 2500+ elo games and the first positive result was a fact.

But the obvious best result gave an EOC database made by 6700 (quality!) games Pro Deo played itself. If you think about it for a while it's not such a big surprise as the created chess tree reflects the total history of the opening and middle game Pro Deo has played, avoiding bad lines and stimulating good lines. As such the system more or less automatically functions as a learner, especially since the EOC database is updated when the result of a game becomes known, score: +5.00 cq -5.00

This was a fun project and I am open to offer my help to anyone who wants to add this technique to his/her engine.

Ed