Polyglot++ simplified

Simplified

Poly 1.6

This page is about POLY 1.6, a continuation on the 5 first versions. After intensive testing we concluded that from all the options available from version 1.2 and 1.5 the WLD (win|loss|draw) approach gives the best results. With version 1.6 we like to present a number of (reasonable well) tuned polyglot opening books included in the download.


For this purpose (from MillionBase 3.45) we created 5 regular polyglot books based on a minimum human elo of: elo2500, elo2600, elo2650, elo2700, elo2750 and 1 polyglot book from CCRL 40/15 games played by engines with a minimum elo of 3300. Six matches of each 5000 games with the new Stockfish 12 should give us insight which book scores best. For reference we use the last handcrafted ProDeo book from Jeroen Noomen.

Poly 1.6 book matches vs ProDeo book

Book

WDL factor

Games

Score

ELO

elo-2500

250

5000

53.6%

+26

elo-2600

250

5000

55.1%

+35

elo-2650

250

5000

56.1%

+42

elo-2700

250

5000

56.6%

+46

elo-2750

250

5000

55.5%

+38

elo-3300

250

5000

54.6%

+32

Best book between 2700+ elo rated human players.


The WDL factor - all 6 books are tuned with a (flexible) value between 1 and 500. In our current case we used an educated guess of 250 which already gives excellent results.


In a nutshell, a low value makes a book very random, a high value narrows the book.

The following example makes the effect visible and note what happens to the weights of the big-four 1. e4 | 1. d4 | 1. Nf3 | 1. c4


You can change the weights using the function key F10, select the book, type the new WDL factor (1-500) and a new book is created called NEW.BIN in the BOOKS folder and perhaps create an even stronger book.


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Credits


Thanks to the Stockfish team for the use of

Stockfish 12

and

Fabien Letouzey

for Polyglot