Piece value
Posted: Wed Nov 14, 2018 5:38 pm
A simple piece value calculation applied to FIDE chess and Musketeer chess variant pieces.
Piece Value Calculation ms doc format
Piece Value Calculation ms doc format
Thanks for sharing. I did genetics before, it is fun. This crossover/mutation is interesting, transferring good genes to other personalities in the population. I hope to create a framework for this when I have more time.MarkZH wrote: ↑Thu Jun 03, 2021 7:30 amA long while ago, I was asked to use my genetic chess software to try to work out semi-empirical values for the fairy pieces of musketeer chess. My program (GitHub repository) improves itself through evolution: randomly mutated players play a game, after which the winners mate and produce mutated copies.
MarkZH wrote: ↑Thu Jun 03, 2021 7:30 amA long while ago, I was asked to use my genetic chess software to try to work out semi-empirical values for the fairy pieces of musketeer chess. My program (GitHub repository) improves itself through evolution: randomly mutated players play a game, after which the winners mate and produce mutated copies. This way, various parameters of a chess engine's evaluation function and time control strategy slowly improve. One set of parameters are the piece values.
After a long delay (programming the rules of Musketeer chess, getting a new job, moving to a new city, etc. etc.), I was able to get some results.
The issue where the discussion took place is here.
The post with the results, detailed discussion, and pretty graphs of piece value evolution is here.
I performed several runs in which only two fairy pieces were used for all games. This was done to save time since it would take far too many games to successfully evolve all of the fairy piece values at the same time. If every piece could be chosen for the games, piece value mutations would often have no effect on the survival of the player since there would only be a 1/5 chance of that piece being chosen for a game. The pieces' gated positions were chosen randomly.
Here's a summary of the data.
musketeer results.PNG
The first two columns in the table are the name of the piece and its symbol. The next 6 columns are 6 runs of the program. The two-letter labels indicate which fairy pieces that were used during that run. The numbers in that column indicate the values that resulted after a long run of the program (the numbers in the bottom row are how many games were played during each run). So, in the first column, every game was played with the Cannon and Dragon. The last run column, labeled "DS (check)" was a run with the Dragon and Spider pieces to check whether similar values would be obtained as previous runs when the Dragon and Spider were paired with other pieces (the Dragon was close, the Spider not as close). The next column, "Mean," is the mean value of the piece through all the runs. The "MusketeerChess.net" column lists the piece values from this site. The last column is the difference in piece values between these genetic results and this site.
A note about the king value: Since the king is never removed from the board, its piece value is only under weak evolutionary pressure. Its value changes wildly from run to run.
Interesting results
The piece value results for the Archbishop, Cannon, Fortress, and Chancellor were within half a pawn of the values given on this site.
The piece values for the Dragon (+1.42), Elephant (+2.20), Hawk (+2.02), Leopard (+1.95), Spider (+1.98), and Unicorn (+1.66) were more valued by about two pawns as compared with this site's values.