Metadynamics bias exchange on GPUGRID

Preliminary notes on sending a BE (Piana, J. Phys. Chem. B 2007, 111, 4553-4559) simulation on GPUGRID. BE allows one to have metadynamics on multiple CVs, scaling linearly rather than exponentially with respect to the dimensionality.

Setup

The BE_setup command organizes a directory hierarchy as follows

   BEname/in/...      <-- put your input files here
         /config/...  <-- configuration variables
         /results/... <-- returned files
         /stage/...   <-- temporary area
         /bin/...     <-- executables

Follow the instructions on the screen. In principle one only needs to deal with the "in" directory.

Caveats

The following values should be equal
- Restart frequency
- Print stride
- Hills deposition frequency
Run length should be a multiple of the above
WU will be named C<n>R<m>S<s>, where <n>=1..N is the CV, <r>=1..M is the replica, and <s>=0..inf is the step.