Eight Queens GA
This is an example of a specific implementation of a simple genetic algorithm using https://github.com/bartvig/simple-ga
The eight queens puzzle is the problem of placing 8 queens on a chessboard, so that no two queens threaten each other, i.e. so that no two queens are on the same row, column, or diagonal.
Make sure SimpleGA is in the right folder or change the folder in line 3 of queens.php. Then run composer install. Then you might have to run composer dump-autoload -o to make autoloading work properly.
How to install composer is out of scope for this documentation.
php queens.php
Execution will stop when a correct solution is found, or the genetic algorithm has run for the configured number of generations.
For each generation the most fit solution is output to the screen.
The following variables can be configured in queens.php (see https://github.com/bartvig/simple-ga for an explanation of the variables): population_size, population_random, elite_count, and mutation_promille. If you want to change the max executed number of generations, change the variable $generations.