[gmx-developers] replica exchange
hessb at mpip-mainz.mpg.de
Tue Mar 11 17:08:55 CET 2008
servaas michielssens wrote:
> I have a question about the repl_ex.c file in gromacs-3.3.2, in the
> function replica_exchange( ) gmx_sum is called (line 10 in this
> function). If I understood this correctly this function calculates the
> sum of the potential energy on all nodes. I don't understand why this
> function is called, why do you need the sum of the potential energies
> of all the replica. Or is this just something to check that everything
> is still ok on all the nodes?
No, this is a lazy way of communicating the energies.
Each process fills one entry in an array of size #processes and then the
array is summed
over the processes.
We already had this call and for this very infrequent event, I did not
want to implement
another MPI routine to communicate energies.
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