Levis: Programming by the Seat of Your Genes

A toolkit for genetic algorithms in Python, written as a companion to a technical talk.

Overview

The levis package contains a collection of genetic traits meant to be composed to achieve a desired algorithm behavior.

To implement your own GA, you will probably want to extend from one of the classes in selection and one of the classes in logger. The former will give you proportionate or tournament selection, and the latter will enable logging (including verbosity).

You'll also want to override the crossover() and mutate() methods with implementations from the packages by the same name.

The examples each have three components: a genetic solution, a method to generate data, and a main method to wire in command line arguments. The examples will respond to a -h flag to display help.

Getting Started

Prerequisites

Levis currently targets Python 2.7 and has no external dependencies for basic use. Image rendering in the examples, when implemented, relies on svgwrite, and some data generation needs Faker.:

$ pip install svgwrite
$ pip install fake-factory

Installing

Install by cloning the git repository. Installation via PyPI is coming soon.:

$ git clone https://github.com/rawg/levis

Running Examples

If you're looking at this project, you're probably more interested in the example implementations than in the core genetic behaviors. Each *.py file in the examples/ folder should respond to a -h argument to list its options. All should run without any options, but you'll want to tweak the parameters to better understand each algorithm.:

$ cd examples/
$ python knapsack01.py -h
$ python knapsack01.py --iterations=10 --population-size=5

Testing

Running the Unit Tests

Embarassingly, there aren't that many to run! Test suites can be run individually, like so::

$ cd tests
$ python test_crossover.py

Testing Code Style

The code is run through pylint, if that sort of thing interests you. Note that many pylint warnings are currently ignored, but it's good to know your faults.

Future Items

• [ ] Python 3 support
• [ ] Alternative end conditions
• [ ] Cycle crossover
• [ ] Merge crossover
• [ ] Explicit "cut-and-splice" crossover (use n-point in the meantime)
• [ ] Separate traits for logging behavior
• [ ] NewBestScore to add a trigger for when a new high score is seen
• [ ] Clean up handling of configuration and CLI arguments
• [ ] More tests

Versioning

Version numbers follow the SemVer scheme. For the versions available, see the tags on this repository.

Authors

Only one soul can be blamed for this:

• Jeremy Fisher, @thisisroot.

License

This project is licensed under the MIT License - see the LICENSE.md file for details.