[petsc-dev] Ghost update in VecAssembly?

[Jed Brown]

Matthew Knepley <knepley at gmail.com> writes:
>> ghost values.  Also, who uses VecGhost _and_ VecAssembly for the same
>> Vec?  That's quite wasteful; if you have local indexing, why not just
>> use VecGhostUpdate(...,SCATTER_REVERSE)?
>>
>
> I do not understand this argument. If you form the local part of each vector
> using VecGetArray(), then you must call both VecAssembly() 

No.  You only need to call VecAssembly if you use VecSetValues.  But if
you have a ghosted vector, you would normally use VecGetArray and never
bother with VecSetValues.

> and VecGhostUpdate(), which I think is the complaint.

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