Ghosts and Extents (was [vtkusers] vtkImageImport in java?)

[David E DeMarle]

Ghost levels are used in VTK parallel applications to keep track of 
which cells/points are managed by the local processor and which are just 
kept locally for convenience.

With four points, two processors and one level of ghost cells the two 
processes ghost level arrays would look something like this:

P0[0 0 1 -]
P1[- 1 0 0]

Here each process owns two points (marked with a 0), keeps around one 
point owned by the other (marked with a 1) and doesn't have any 
information at all about the last point (marked with a -).

hth
Dave DeMarle

>-Steve
>P.S.  I still don't know what ghost levels are.  Anyone?
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