The OPAL Discussion Forum

["Adelmann Andreas (PSI)" <andreas.adelmann AT psi.ch>]

Hi Sherlp

Dear all,

While computing self-field in OPAL-CYCL, a cubic domain containing all
macroparticles is created and then discretized. After that, all particles are
scattered on the grids. And I have found the scatter() function whose
annotation says 'scatter particles charge onto grid' at(although I don't know
how it actually works)

https://gitlab.psi.ch/OPAL/src/-/blob/master/src/Classic/Algorithms/PartBunch.cpp#L640

yes that is the place and it does a cloud in cell (CIC) interpolation, as the third argument of scatter indicates. 

And I got this from computeSelfFields_cycl() function at

https://gitlab.psi.ch/OPAL/src/-/blob/master/src/Algorithms/ParallelCyclotronTracker.cpp#L3368

But I couldn't find any statement to create the whole physical domain to
discretize and scatter particles.

well I am confused: you just found the scatter function. Setting up the computational domain is at 

https://gitlab.psi.ch/OPAL/src/-/blob/master/src/Track/TrackRun.cpp#L462

in setupFieldsolver(). 

Hope that helps!

Cheers A 

I think the statement should be after the time integration of bunch and before
the next scattering on grids to compute self-field because we should know the
position and boundary of bunch to contain all macroparticles but I still
couldn't find it.

Best regards,
Sherlp