[petsc-users] Field dependent stencil in DAs

[Ethan Coon]

On Mon, 2011-07-11 at 19:28 -0400, Kevin Green wrote:

> Now the real reason I came:  Is there some sort of mask that can be applied to the DAs that would turn off the communication of ghost points for some degrees of freedom? 

No.  However, it would be easy enough to create a 1-dof DA of the same (local and global) sizes as your 5-dof DA, create a Vec using that dof, scatter between the 5-dof Vec and the 1-dof Vec (see VecStrideGather()), then communicate only this 1-dof Vec.

Ethan



>  I assume that the communication structures are set up so that only a single message needs to be passed between communicating processes on update, but this still results in passing 5X the data that I have to.  Any comment on this would be much appreciated.
> 
> Thank you,
> Kevin

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Ethan Coon
Post-Doctoral Researcher
Applied Mathematics - T-5
Los Alamos National Laboratory
505-665-8289

http://www.ldeo.columbia.edu/~ecoon/
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