[OSGeo-Discuss] Iteration and supercomputing with GRASS GIS

[Johannes Radinger]

Hello,

I am very new to GRASS GIS!
At the moment I am working with ArcGIS10 to develop a dispersal model 
(raster based) which
involves single calculations for each raster cell (around 20 000 
calculations) conducted by an iteration process over the cells of the 
input raster.
As this takes quite long, a change to a Linux based software and  the 
use of a supercomputer (mulitcore) is considered. Therefore especially 
GRASS GIS sounds interesting to me for the soltution.

How are iterations (like in the ArcGIS10 modelbuilder) solved in GRASS 
GIS? Is that possible?
Is it possible to perform the single calculation in parallel mode and 
use a multicore Linux supercomputer e.g.?
Does anyone have experience with such approaches?

Thank you very much.

/j