[Trilinos-Users] zoltan particle ghost regions

Biddiscombe, John A. biddisco at cscs.ch
Mon May 23 09:01:25 MDT 2011


Lee Ann,

I got back to this and particle repartitioning is working nicely -  I was pondering the ghost cell sending.
I looked again at the migration example page and wondered ...do I need to bother with Zoltan_Invert_Lists
it seems to me that I can just make up my own lists (the zoltan_rcb_box works fine and helps) of Ids and destinations, package them up in a call to zoltan_migrate and do everything 'custom'.

Can I call Zoltan_migrate with all my own data pointers? is there any reason why I have to use lists zoltan has created? I'm guessing that I can do what I want providing I package up everything using the callbacks, but I may find out the hard way that I can't - hence I'm asking beforehand ...

thanks

JB

-----Original Message-----
From: Riesen, Lee Ann [mailto:lriesen at sandia.gov] 
Sent: 03 May 2011 20:36
To: Biddiscombe, John A.; trilinos-users at software.sandia.gov
Subject: RE: zoltan particle ghost regions

I should also mention that if you are partitioning with axis-aligned spatial regions (the RCB method) you can use Zoltan_RCB_Box to obtain the boundaries of the region, which may help you determine how close your points are to a region.
---
Lee Ann Riesen
Sandia National Laboratories, Albuquerque, NM, USA
Department 1426, Scalable Algorithms, Computing Research Center
505-844-2059
________________________________________
From: Riesen, Lee Ann
Sent: Tuesday, May 03, 2011 12:31 PM
To: Biddiscombe, John A.; trilinos-users at software.sandia.gov
Subject: RE: zoltan particle ghost regions

Hello John.  Zoltan does not explicitly support any level of ghost points.  It simply maps each point being partitioned to a single part number.  When the application migrates the points to the new part, it can also send neighbors that are not assigned to the new part as ghost points.

If you are using Zoltan to migrate the points, you can include in your callback functions the movement of the ghost points.  That is what is being described in the example you referenced.

I hope this helps.

Lee Ann
---
Lee Ann Riesen
Sandia National Laboratories, Albuquerque, NM, USA
Department 1426, Scalable Algorithms, Computing Research Center
505-844-2059
________________________________________
From: trilinos-users-bounces at software.sandia.gov [trilinos-users-bounces at software.sandia.gov] on behalf of Biddiscombe, John A. [biddisco at cscs.ch]
Sent: Monday, May 02, 2011 3:48 AM
To: trilinos-users at software.sandia.gov
Subject: [Trilinos-Users] zoltan particle ghost regions

If using zoltan to redistribute particles between processes. Is it possible to ask for all points within x units of a boundary to be duplicated as ghost points and copied to all overlapping processes.

I had a quick look here which gives me some clues, but if there's an example already out there, please let me know.
http://www.cs.sandia.gov/zoltan/ug_html/ug_examples_mig.html

thanks

JB

--
John Biddiscombe,                            email:biddisco @ cscs.ch
http://www.cscs.ch/
CSCS, Swiss National Supercomputing Centre  | Tel:  +41 (91) 610.82.07
Via Cantonale, 6928 Manno, Switzerland      | Fax:  +41 (91) 610.82.82




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