This Rust codebase contains a library crate, mixed-strategies, for computing optimal mixed strategies and game values given the payoff matrix for a classical two-player zero-sum game.

A simple driver program is also provided that reads a payoff matrix (as ASCII text) from standard input and displays the game solution. The examples/ directory in this distribution contains a number of example payoff matrices.

The code in this distribution is an implementation of algorithms described in the most excellent book

The Compleat Strategyst
John D. Williams
RAND Commercial Books 1954
https://www.rand.org/pubs/commercial_books/CB113-1.html

It's fantastic that The RAND Corporation has chosen to provide a free PDF of this book for download: my paper copy is getting pretty dog-eared. I highly recommend this book as an introduction to game theory. All errors and bugs in the implementation are, of course, my own.

Please see the rustdoc for usage of the library crate.

Example session (for a rock-scissor-paper game):

$ cargo install --git https://github.com/BartMassey/mixed-strategies-rs
...
   Installed package `mixed-strategies v0.1.0 (...)` (executable `mixed-strategies`)
   
$ printf -- '0 1 -1\n   -1 0 1\n   1 -1 0\n' | mixed-strategies  
value 0.000
max 0:0.333 1:0.333 2:0.333
min 0:0.333 1:0.333 2:0.333

Meaning expected game outgome is neutral for both players, and each player should choose row (column) with equal probability.

This started out to be a port of my Haskell implementation also called mixed-strategies. If you want Haskell instead of Rust, you can check that out: it's quite similar. I gave up on the port when I realized it would be easier to reimplement from scratch than to understand my old Haskell.

Bart Massey

This program is licensed under the "MIT License". Please see the file LICENSE in the source distribution of this software for license terms.