Correction: the stub function to reproduce the problem should read:
c_ssti_forces( f, istart, iend ){
for(int i = *istart - 1; i < *iend; i++){
f[i * 3] *= 0.5;
f[i * 3 + 1] *= 0.5;
f[i * 3 + 2] *= 0.5;
}
return();
}
On Tue, May 3, 2011 at 2:47 PM, Josh Berryman <
the.real.josh.berryman.gmail.com> wrote:
> Hello Devs, I am writing a module which plugs into the amber code in the
> following way:
>
>
> I runmd I have this code:
>
> call force(xx,ix,ih,ipairs,x,f,ener,ener%vir, &
> xx(l96),xx(l97),xx(l98),xx(l99), qsetup, &
> do_list_update,nstep) !call force() in the normal place
>
> call c_ssti_forces( x, f, .... ) !modify the forces for nefarious
> purposes
>
> ... the c_ssti_forces() function modifies the interactions; it is part of
> a TI thing that I am trying out. In serial, this very simple scheme for
> modifying the forces seems to work; but for more than one processor; I have
> problems. The most simple function for c_ssti_forces() which gives
> divergence is:
>
> c_ssti_forces( f, istart, iend ){
>
> for(int i = istart - 1; i < iend; i++){
> f[istart*3] *= 0.5;
> f[istart*3] + 1 *= 0.5;
> f[istart*3] + 2 *= 0.5;
> }
> return();
> }
>
> The behaviour is odd: for serial, with istart = 1 and iend = natoms; this
> stub function just damps the dynamics a bit, as you might hope. For
> parallel (with various valued of istart and iend fished out of the code, eg
> based on iparpt in the fsum function) the temperature blows up and the
> simulation explodes. What is going on? How do I alter forces in a parallel
> run? I get the same behaviour with the thermostat turned off or on.
>
> Josh
>
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Received on Tue May 03 2011 - 06:00:04 PDT
