Dear all,

Let X be a computational domain, covered by a Mesh on which an 
EquationSystems object is based on.  Let X2 be a subset of X, given by 
the union of selected grid elements (which are, say, marked by certain 
values of subdomain_id).

Assume I want (at some point in my application) to solve a system only 
on X2 (say, using Dirichlet boundary conditions on all boundaries of 
X2 that are not boundaries of X).

I can easily achieve this by assembling Dirichlet conditions 
everywhere ouside X2 and then solving as usual.  However, then I 
cannot benefit from the performance gain that I should theoretically 
have if X2 contains much less elements than X.  This is in particular 
true if I am using a direct solver (such as SuperLU_DIST, wrapped via 
PETSc).

What is the easiest way to do this more efficiently, that is,

(1) let SuperLU_DIST only see the necessary part of the matrix,

(2) if possible, guarantee a sensible load-balancing, and

(3) not run into problems due to dofs that appear free if viewed from 
inside X2 but are actually constrained in X

?

Thank you in advance for your ideas.

Best Regards,

Tim

-- 
Dr. Tim Kroeger
CeVis -- Center of Complex Systems and Visualization
University of Bremen              [email protected]
Universitaetsallee 29             [email protected]
D-28359 Bremen                             Phone +49-421-218-7710
Germany                                    Fax   +49-421-218-4236

------------------------------------------------------------------------------
This SF.net Dev2Dev email is sponsored by:

Show off your parallel programming skills.
Enter the Intel(R) Threading Challenge 2010.
http://p.sf.net/sfu/intel-thread-sfd
_______________________________________________
Libmesh-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/libmesh-users

Reply via email to