[FLASH-USERS] Prolonging/restricting values

[Seyit Hocuk]

Dear users,

I have made a column density calculation routine that sort of does not 
require to calculate the complete column density at every timestep, but 
needs a small update on the differences between current and last 
timestep. This works fine, 99.5% accurate, but everytime there is a 
refinement step, my column densities are messed-up and I need to do the 
full column density calculation. This is expensive and slow. I suspect 
that this problem arises from the prolongation (or restriction). I am 
currently doing hydro (amr) simulations with self-gravity (multigrid) 
and I remember that you could make your own simple prolongation for MHD 
simulations.

Can I make my own simple (perhaps like injection) prolongation without 
altering the main code much. I just need a simple prolongation, but only 
for column densities. The other variables need to be unaffected. Perhaps 
something like changing the type of the variable. My column densities 
basically increase from the edge of the simulation box to the center. 
Other ideas are also welcome, like DON'T Refine so OFTEN! nstep=1,000,000 :)

My geometry is carthesian, boundaries are periodic. I use PPM and refine 
every 2 steps. Furthermore, I include heating, cooling, turbulence 
(stirring), multispecies+multigamma, particles, and a few other 
self-made small routines.

Thanks,
Seyit



-- 
With kind regards,
Seyit


S. Hocuk
Postdoctoral Researcher
Kapteyn Astronomical Institute
P.O. box 9700
Groningen, the Netherlands