[petsc-users] questions about PetscSF

[Jed Brown]

Fande Kong <fd.kong at siat.ac.cn> writes:

> Hi all,
>
> I was wondering mechanisms of the object PetscSF. What are definitions of
> roots and leaves? Do roots/leaves associate with the data we want to
> receive/send?  For the function Bcast, it seems that we transfer data from
> roots to leaves. But in another function Reduce, it seems that we move data
> in the opposite direction (from leaves to roots). These kind of mechanisms
> possibly make users confused.

The SF graph is asymmetric so that it can have cleaner semantics.  Read
my note and reply here if something is still unclear.

http://59a2.org/files/StarForest.pdf
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