@seanmor5 - This is a great book so far… I’m enjoying reading and coding along with it!

Quick question, though - since “evaluate” goes to the trouble of calling the “fitness_function” and generating an updated list of Chromosomes with the new calculated “fitness” values in the struct, instead of ending the function with this (where it has to call the “fitness_function” a bunch more times):

 |> Enum.sort_by(fitness_function, &>=/2)

why not end it with this (in order to use these pre-calculated values)?

|> Enum.sort_by(& &1.fitness, &>=/2)

Also, I’m kinda sad that you dismissed the tree-type genetic programming like John Koza did in the 60s and 70s (to generate electronic circuits and a whole bunch of other cool stuff), but that is a huge topic in itself. Also, I’m extremely interested in Gene Expression Programming invented by Dr. Candida Ferreira, but that is also tree-type.

Anyway, thanks for the great book, and I look forward to your updates!

– Glenn