FRESHS is a sampling harness system to carry out rare event simulations, using algorithms such as SPRES or FFS.
FRESHS is simulation-agnostic: it is tested against popular simulation programs (GROMACS, LAMMPS, ESPResSo) but you should find it easy to connect it to your own programs without recompiling them using our plug-in system.
The classic example of a rare event is nucleation, such as the formation of a raindrop from water vapour - this happens every day, but it is rare on the timescale of motion of the water molecules. For this reason, a basic computer simulation of oversaturated water vapour is not enough to study the formation of the raindrop. Various improved sampling methods for computer simulations have grown up to address this difficulty; FRESHS is an attempt to bring them together and make them easy to use.
You can learn more about the rare event sampling algorithms which we currently implement on the publications page of this site. A tutorial is available in the tutorial directory of your freshs snapshot. At present we only implement a small subset of the algorithms which have been presented in the large, and often repetetive, literature on the subject.
FRESHS is an open source project: if you have an algorithm which you would like to contribute, the harness has been designed such that this should be relatively easy for you to do, instantly making your method available to users of all the implemented simulation packages. We hope that in time FRESHS will become the platform of choice for validation, comparison and distribution of rare event sampling methods.