/lindenmayer_systems

Lindenmayer systems experiments

GNU General Public License v3.0GPL-3.0

TL;DR

Collection of personal experiments around artificial life, lindenmayer systems, formal grammars, fractal generation, and evolutionary algorithms

Setup

I chose to use Turtle for my graphics because it already comes pre-packaged with Python and follows the general "batteries included" philosophy. Because of this, all you have to do is copy the specific *.py script you'd like and run that. Alternatively, if are a bit more advanced in your software skills, you might want to consider following the steps below.

1) Installing dependencies:

If just using venv, create a virtual environment named venv_linden using: python3 -m venv venv_linden

If additionally using Pyenv to manage and easily switch between multiple Python versions (recommended practice), create a virtual environment using:

pyenv virtualenv <python_version> <environment_name>

See tutorial here for more on Pyenv. Since some of the above graphics-based code relies on a pre-installed Python library called Turtle which itself relies on Python's standard GUI package Tkinter, you might run into problems with Tkinter if you are running on a device that's updating to MacOS Big Sur (as of 12/23/2020). If you do, you might need to install different Python versions via the patch found here by @htp 8/31/2020.

Then activate the environment:

(Just using virtualenv) source venv_linden/bin/activate

(Using Pyenv's virtual environment) pyenv local myproject

The latter command creates a .python-version file in your current working directory from which you run eval "$(pyenv virtualenv-init -)" in your environment, allowing the environment to automatically activate upon entry into that directory (nifty!) Alternatively, you can manually activate your Pyenv environments using pyenv activate <environment_name> and deactivate using pyenv deactivate.

Then install any necessary packages or other dependencies I have (not required as of 12/23/20, but might need to do later down the road): pip install -r requirements.txt

2) Troubleshooting:

  • See here if you are having trouble with Tkinter running on your device.

Sources:

  • See here for a beginner's tutorial on how to use Turtle in Python. I chose Turtle since it is a pre-installed Python library and follows the general "batteries included" philosophy.

  • See here for an alternative to the Turtle package called PyGame. This should be more familiar to graphics/game programmers but is still low-level enough for beginners. Note that if your examples aren't running and you are using a recent version of Mac OS X, it might be a problem with the interaction between pygame and virtualenv. More details here.

  • See here for The Algorithmic Beauty of Plants by Przemyslaw Prusinkiewicz (director of the Computer Graphics group studying Fibonacci numbers and modeling using grammars) and Aristid Lindenmayer (a theoretical biologist studying sequence generators). This textbook is based off Lindenmayer's original notes discusssing the theory and practice of Lindenmayer (L-)Systems for modeling plant growth. It provides much of the theoretical material from which I will be drawing from.

  • See here for my sequence of articles on Lindenmayer Systems from the perspectives of theoretical biology, artificial life, physics, mathematics, computation, linguistics, and philosophy.