From PLUMED community

We are very pleased to announce that PLUMED2 is available at www.plumed-code.org.

Version 2.0 is a complete rewrite, so there is no way to write a complete set of differences with respect to PLUMED.

Here is a summary of the major differences:
- The input is simpler and more error proof. Many checks are now performed in such a way that common errors are avoided.
- The units are now the same for all MD codes.  If you want to use different units than the default ones, you can now set them in the input file.
- The analysis tools are now much more flexible.  As an example of this it is now possible to write different collective variables with different frequencies
- Many complex collective variables are considerably faster with respect to PLUMED1. In particular, all variables based on RMSD distances.
- Centers of mass can be used as if they were atoms. Hence, unlike PLUMED1, you can use center of mass positions in ALL collective variables.
- The virial contribution is now computed and passed to the MD code.  Plumed can thus now be used to perform biased NPT simulations

In addition, it is now much easier to contribute new functionality to the code because:
- There is a much simpler interface between PLUMED and the MD codes. This makes it much easier to add PLUMED to a new MD code.
- PLUMED2 is written in a C++ object oriented programming and it is fully compatible with the C++ standard library
- PLUMED2 is based on a modular structure
- An extensive developer and user documentations are provided with the code

While PLUMED2 includes many more functionalities with respect to PLUMED1, some other are missing and will be implemented shortly.
Check the User manual in the How tos section about how moving from PLUMED1 to PLUMED2.

More information can be found in the PLUMED2 paper, available on arxiv:

http://arxiv.org/abs/1310.0980

and on the Computer Physics Communications website:

http://www.sciencedirect.com/science/article/pii/S0010465513003196

The PLUMED developers team.--