This package implements the "fix plumed" command, which can be used
in a LAMMPS input script.

The fix allows enhanced sampling methods such as umbrella sampling and 
metadynamics to be used.  Furthermore, PLUMED can be used to perform a 
wide range of analyses on trajectories on the fly as they are generated.

The package uses the "PLUMED" library, whose source code is not included
in the LAMMPS source code distribution. The files in the USER-PLUMED package 
folder implement an interface between LAMMPS and PLUMED, that are written 
and maintained by Gareth Tribello (gareth.tribello@gmail.com).

PLUMED must instead be downloaded and compiled separately to LAMMPS.  This building 
and compiling of PLUMED can be done before or after the building of LAMMPS as LAMMPS 
can call PLUMED as a dynamic library.  There is also the possibility to link PLUEMD 
statically.  In this case a copy of PLUMED must be downloaded into the lib/plumed 
directory.  This copy of PLUMED will then always be linked into the code at compile 
time. 

However you decide to link PLUMED (statically or dynamically) you must run the command:

make yes-user-plumed

before compiling LAMMPS in order to enable the module.   In addition, if you have chosen to 
link PLUMED dynamically you must ensure that PLUMED is in your 
PATH when running a LAMMPS calculation that takes advantage of PLUMED.  If 
PLUMED is linked as a runtime library and if PLUMED is not in the PATH an error will be returned whenever LAMMPS encounters 
the fix plumed command in its input.  To be clear, however, a LAMMPS executable that was dynamically linked with PLUMED will run 
even if PLUMED is not in the path if as long as the input does not contain a fix 
plumed command.

If you wish to statically link PLUMED you must download PLUMED to the /lib/plumed directory before compiling LAMMPS.  You can 
download a tar ball into that directory or you can clone the plumed2 repository from github there.  Once you have created a 
directory containing a distribution of PLUMED within /lib/plumed you then must build PLUMED within that directory by issuing 
the usual commands.  It is worth noting that we have provided a script that will download and build PLUMED for you with 
a minimal set of options.  To run this script you need to issue the following command:

make lib-plumed args="-b"

in the src directory. 

More info about the PLUMED library can be found at:

www.plumed.org

and in the reference articles:

PLUMED2: New feathers for an old bird
G.A. Tribello, M. Bonomi, D. Branduardi, C. Camilloni and G. Bussi,
Comp. Phys. Comm 185, 604 (2014)
https://doi.org/10.1016/j.cpc.2013.09.018

PLUMED: a portable plugin for free energy calculations with molecular dynamics
M. Bonomi, D. Branduardi, G. Bussi, C. Camilloni, D. Provasi, P. Raiteri, D. Donadio, F. Marinelli, F. Pietrucci, R.A. Broglia and M. Parrinello
Comp. Phys. Comm. 180, 1961 (2009)
https://doi.org/10.1016/j.cpc.2009.05.011

Instructions explaining how to use PLUMED and LAMMPS in tandem can be found on the PLUMED website, which also gives 
numerous example scripts for PLUMED as well as citations to articles that dcoment the various methods that are 
implemented within PLUMED.

There are also example scripts for using this package in the folder
examples/USER/plumed, as well as on the GitHub page for PLUMED.

Please contact Gareth Tribello (gareth.tribello@gmail.com) for questions
regarding this package.

---------------------------------

Version: 2016-12-22
