itaps-parallel removal of

[Onkar Sahni]

>
> In the specific case of repartitioning, it knows because every entity
> comes to it with a part handle attached.

  every local entity comes with local part-handle(s) (may be neighbors
touching each other for graph-edges crossing inter-part/process bdry.)
and how can a partitioning service then get local part-handle(s)
transported to remote parts/processes. This is exactly the point I was
trying to make during boot-camp.

During file I/O (parallel read) I think (as of now) we will have to talk
in terms of integers for part IDs (or may be pair of integers) and map
these to processes/ranks (this map could default to something but can be
provided by application).

- Onkar

>
> I'll admit I hadn't thought about (one of?) the bootstrap problem: how
> does a parallel read manage to work out which part handle for some
> remote part goes with however the part is identified in the file?  I can
> imagine any number of really bad, expensive ways to do that, but having
> a mapping from part number to part ID would be cleaner, more accurate,
> and faster.
>
> So in the end, I think Mark's got me convinced of the need for a
> function to do this mapping.  I think it's possible to implement this in
> a way that requires no communication (and not too much storage, at least
> in common cases), although obviously this mapping will have to be one of
> the things that updatePartitionAll updates.

  If we reserve bits (fixed m and n across processes), then I think
updatePartitionAll do not necessarily need to do anything extra for part
IDS (and their mapping).

- Onkar

>
> Carl
>
> --
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> Dr. Carl Ollivier-Gooch, P.Eng.                   Voice: +1-604-822-1854
> Associate Professor                                 Fax: +1-604-822-2403
> Department of Mechanical Engineering             email: cfog at mech.ubc.ca
> University of British Columbia              http://www.mech.ubc.ca/~cfog
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