[lammps-users] Parallel Replica Dynamics w/ LAMMPS?

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1

Hi All,

I am curious if anyone on the list has tried to set up a parallel replica dynamics (accelerated MD method developed by Art Voter of LLNL and coworkers) run using LAMMPS as a base. It is essentially running a group of nearly identical simulations in parallel, with periodic communications between them.

One of the things that is needed for PRD to work is a sort of ‘wrapper’ which will allow for the creation of the replicas and starting the simulations, allow the replicas to communicate if a transition has been detected in one of the replicas, and if so, to stop all the others, then communicate the state of the replica that had the transition to the other replicas(perhaps create some output), and repeat the process.

Add added complexity will come in the fact that I will have to deal with a batch scheduler system too, because I am using an HPC center machine.

Anyone ever try anything like this?

Dave

David E. Farrell

Graduate Student

Mechanical Engineering

Northwestern University

email: d-farrell2@…435…

2

LAMMPS has a temper command which runs multiple
simulations simultaneously and compares their temperatures
periodically. It sets up groups of processors in the
way you suggest (via the command-line switch -partition)

Steve

3

However, I wonder if there is anything in LAMMPS to search for
saddle-points and detect transitions through them (I confess I have
not read the whole manual). It does have a minimize command and a
min_style command that implements various conjugate-gradient methods
to go to minimum energy positions of the atoms. Therefore I guess
there will be some work to be done in LAMMPS to simulate parallel
replica dynamics (PRD).

It might be worth doing it if one has a large number of processors and
want to explore transitions that have an average time between 10
nanoseconds to microseconds depending on the number of processors you
have at this point in time on the Moores law curve.

Best Regards,
Manoj

4

There is nothing currently in LAMMPS to search for saddle points.

Steve