[vsipl++] Ideas on overlapping distributions

[Stefan Seefeld]

Jules,

thanks for writing this up. Are you going to add that to the Stencil wiki page ?


Jules Bergmann wrote:

> Use cases
> ---------
> 
> 1. STAP
> 
>   Start with tensor of processed radar data.
>   Compute weights based on solving linear system consisting of neighborhood
>   around pixel
> 
>   Distributed processing requires overlap, potentially wrap-around
>   to deal with circular frequencies.

Interesting. So we have at least three different 'boundary conditions' already:

1) zero padding
2) constant padding (use the boundary value to fill)
3) periodic boundary conditions

> 3. Physics.
> 
> TODO: processing example that requires guard cells.

I guess any PDE would do. Depending on the degree, this may involve a single
line of boundary cells, or two (e.g. for diffusion-like equations, involving a
Laplacian).

> Strawman proposal
> -----------------
>  - Add overlap to Block_dist (default value is 0).
>    (possibly have separate left and right overlap).

...and potentially using different boundary conditions in the two dimensions,
depending on the stencil operator.


I need to read and understand all the rest in order to be able to give some
educated comments there. :-)

Thanks,

		Stefan

-- 
Stefan Seefeld
CodeSourcery
stefan at codesourcery.com
(650) 331-3385 x718