[petsc-users] Question about VecScatterCreate's Documentation

Barry Smith bsmith at mcs.anl.gov
Mon Oct 24 15:41:22 CDT 2011


   The indices are ALWAYS with respect to the numbering of the Vec they are associated with. If the Vec they are associated with lives on just that one process (it is a VECSEQ) then you would say it is with respect to the local ordering if the Vec is parallel then you would say it is with respect to the global ordering. But that is the wrong way of looking at it: the indices are simply indices into the correct slot in the Vec.

   Barry



On Oct 24, 2011, at 2:41 PM, Dominik Szczerba wrote:

> Documentations says:
> 
> ix	- the indices of xin to scatter (if PETSC_NULL scatters all values)
> iy	- the indices of yin to hold results (if PETSC_NULL fills entire vector yin)
> 
> Are the indices expected in the application ordering or local ordering?



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