[petsc-dev] IMP prototype

[Jed Brown]

Victor Eijkhout <eijkhout at tacc.utexas.edu> writes:

> On Dec 31, 2013, at 3:10 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
>
>> Hmm, I don't really see the API for specifying the distributions.
>> rightshift->operate(">>1") is a pretty special-purpose interface.
>> Presumably this part is non-collective,
>
> No, it's collective. As I argue in section 1.1, I want sequential
> semantics.

Okay, but surely a more general interface for describing the
distribution must involve setting non-collectively (at least the data is
not collective, so you'll have to build the two-sided representation).

> It's actually not all that special purpose. The shift notation is
> enough if you have stencils with offsets that are constant during
> program execution.

Uh, only for structured grids, and for multiple dimensions, you either
need this communication abstraction to know about multi-dimensional
layout (essentially putting DMDA inside VecScatter) or you can't use the
shift notation.

> And you did read section 2.3, right?

Yeah, it's cute but limited and IMO, not very useful in practice.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 835 bytes
Desc: not available
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20140102/8421b836/attachment.sig>