Customizing Mutation in Your Framework

Genetic Algorithms in Elixir — by Sean Moriarity (59 / 101)

👈 Understanding Mutation | TOC | Implementing Common Mutation Strategies 👉

Just like in Chapter 5, ​Selecting the Best​, and Chapter 6, ​Generating New Solutions​, you’ll need to slightly modify your framework to allow you to customize mutation hyperparameters. These hyperparameters are mutation strategy and mutation rate.

In this section, you’ll create a mutation toolbox and modify your framework to allow you to easily customize mutation in your algorithms.

Creating the Toolbox

First, you need to create a mutation toolbox, just like you created a selection and crossover toolbox. Create a new file in toolbox called mutation.ex.

Next, create the Toolbox.Mutation module, like this:

​ ​defmodule​ Toolbox.Mutation ​do​
​   alias Types.Chromosome
​ 
​   ​# ...​
​ ​end​

You’ll be working a lot with the Chromosome struct in this module, so you’ll want to create an alias. Now, whenever you implement a new mutation strategy, you’ll add it to your mutation toolbox.

Changing Mutation Strategy

Open up genetic.ex and navigate to the mutation/2 function. It looks like this:

​ ​def​ mutation(population, opts \\ []) ​do​
​   population
​   |> Enum.map(
​       ​fn​ chromosome ->…