[gmx-users] Classical Ewald summation

[Justin A. Lemkul]

Andrew DeYoung wrote:
> Hi,
> 
> I seem to remember reading somewhere that the classical Ewald algorithm is
> compatible with particle decomposition runs, but I can't seem to find this
> statement in the manual.  Also, when I try running an NVT simulation with
> either -pd or -dd, I get the following message: 
> 
> "The integration or electrostatics algorithm doesn't support parallel runs.
> Not starting any threads."
> 
> Can you please confirm that the classical Ewald algorithm is not implemented
> in parallel?  And that I'm imagining things thinking that classical Ewald
> was compatible with particle decomposition? 
> 

Per the code in src/kernel/runner.c:

     if (nthreads != 1 &&
         ( inputrec->eI == eiLBFGS ||
           inputrec->coulombtype == eelEWALD ) )
     {
         fprintf(stderr,"\nThe integration or electrostatics algorithm doesn't 
support parallel runs. Not starting any threads.\n");
         nthreads = 1;
     }

Thus the L-BFGS minimization algorithm and the Ewald electrostatics algorithms 
can only be run in serial, as the error message states.

-Justin

-- 
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Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

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