I've been working on graph clustering for visualization since a few years. Following the publication of my latest publication on the subject, I've released the corresponding code.
I'm using a lot R for implementing and testing new research idea, as a data analysis tool and as a teaching support. My modest contribution to this software is a quite complete implementation of Kohonen's Self-Organising Map in the yasomi package.
CloudDALVQ is a Cloud (Azure) implementation of the stochastic vector quantization algorithm (a.k.a., on-line k-means). It has been developed by my (former) PhD student, Matthieu Durut with his colleague Benoît Patra from Lokad. See our paper for details.
I've been involved in two other open source projects in the past: