On Tue, 12 Apr 2011, Boyce Griffith wrote:

> On 4/12/11 1:57 PM, Roy Stogner wrote:
>> 
>> On Tue, 12 Apr 2011, Boyce Griffith wrote:
>> 
>>> If I want something that has the potential to work with ParallelMesh,
>>> is there anything other than PointLocator that could be used to find
>>> the corresponding elements?
>> 
>> You can always construct a map on the coarse elements centroids' -
>> you'll just need to reconstruct it after each repartitioning.
>
> Right; but doesn't that only work for a serial mesh?

Depends on your definition of "work" - on a ParallelMesh it'll only
give you a map from semilocal elements to other semilocal elements.

For mesh-to-mesh projections that's actually good enough, as long as
you also ensure that the two meshes are partitioned equivalently,
which is something you'd probably want to do anyway for efficiency's
sake.

> OK; then this also wouldn't work for ParallelMesh.  Is there any way to find 
> the (possibly remote) element that contains a particular position?

Not easily or efficiently.  Save up a vector of all the positions you
need to look up, alltoall those points, try looking them up on every
processor, send/receive the locations (and the element itself, and its
dof data) back to each of the processors that needed them... at that
point I'd just hardcode SerialMesh.  "I'd" here actually stands for "I
did", not just "I would": the correlation length calculations in my
dissertation are an inherently non-local problem and I was too lazy to
figure out how to parallelize them efficiently.

But hopefully you're not in such a bind; if you're just doing
projections and integration with locally defined integrands, then it
ought to still parallelize nicely.
---
Roy

------------------------------------------------------------------------------
Forrester Wave Report - Recovery time is now measured in hours and minutes
not days. Key insights are discussed in the 2010 Forrester Wave Report as
part of an in-depth evaluation of disaster recovery service providers.
Forrester found the best-in-class provider in terms of services and vision.
Read this report now!  http://p.sf.net/sfu/ibm-webcastpromo
_______________________________________________
Libmesh-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/libmesh-users

Reply via email to