[petsc-users] ASM Index Sets [Repost with Correction]

[Barry Smith]

   Seems ok. You'll need to be more specific about "isn't quite working."

   Barry

> On Mar 23, 2016, at 9:37 AM, Justin Droba (JSC-EG3) [JETS] <justin.c.droba at nasa.gov> wrote:
> 
> Dear all,
> 
> Very sorry to flood the mailing list, one final post because the image will not come through if you're on digest or using plain text.
> 
> Thank you for maintaining this wonderful software and this user mailing list!
> 
> I am attempting to use an additive Schwartz preconditioner with multiple blocks per processor.  I've been able to get it to work with one block per processor but not been successful with multiple. I believe I am not understanding correctly the construction of index sets for this case.
> 
> Let's consider a simple example: 16 nodes on a square with 4 blocks of 4x4:
> 
> <Mail Attachment.png>
> 
> https://farm2.staticflickr.com/1633/25912726941_428d61ae87_o.png
> 
> 
> I want to put Omega_1 and Omega_2 on processor 1 and the other two on the second processor.  Do I make my index sets on processor 1 
> 
> IS = {  {1,2,3,5,6,7,9,10,11}, {2,3,4,6,7,8,10,11,12} }
> IS_LOCAL = { {1,2,5,6}, {3,4,7,8} }
> 
> and similarly for the other processor?  I tried this and it isn't quite working out.  Do I misunderstand something?
> 
> Thank you!
> 
> Best regards,
> Justin
> 
> -- 
> ---------------------------------------------
> Justin Droba, PhD
> Applied Aeroscience and CFD Branch (EG3)
> NASA Lyndon B. Johnson Space Center
> JETS/Jacobs Technology, Inc. and HX5, LLC
> 
> Office: Building 16, Room 142
> Phone: 281-483-1451
> ---------------------------------------------
> 
> 
> 
>