Graph and drawing algorithms framework
Grandalf is a python package made for experimentations with graphs drawing algorithms. It is written in pure python, and currently implements two layouts: the Sugiyama hierarchical layout and the force-driven or energy minimization approach. While not as fast or featured as graphviz or other libraries like OGDF (C++), it provides a way to walk and draw graphs no larger than thousands of nodes, while keeping the source code simple enough to tweak and hack any part of it for experimental purpose. With a total of about 1500 lines of python, the code involved in drawing the Sugiyama (dot) layout fits in less than 600 lines. The energy minimization approach is comprised of only 250 lines!
Grandalf does only 2 not-so-simple things:
It doesn't depend on any GTK/Qt/whatever graphics toolkit. This means that it will help you find where to draw things like nodes and edges, but it's up to you to actually draw things with your favorite toolkit.