libvpsc is a cross-platform C++ library for solving for the Variable Placement with Separation Constraints problem. This is a quadratic programming problem in which the squared differences between a placement vector and some ideal placement are minimised subject to a set of separation constraints. This is very useful in a number of layout problems.

libvpsc is part of the Adaptagrams project. There are no official releases yet, though the code is stable and available from the Adaptagrams GitHub repository.

The API is documented using Doxygen. The documentation you are currently reading can be obtained by running doxygen in the cola directory.

libcola is written and maintained by Michael Wybrow and Tim Dwyer, members of Immersive Analytics Lab at Monash University, Australia.

The algorithms used for VPSC are described in the following papers. If you use libcola, please cite the relevant paper.

• Tim Dwyer, Kim Marriott, and Peter J. Stuckey. Fast node overlap removal.
  In Proceedings 13th International Symposium on Graph Drawing (GD '05),
  volume 3843 of LNCS, pages 153-164. Springer, 2006.