matrix-free additive schwarz?

[P. Aaron Lott]

Hi,
	
I'm new to petsc, and I've been reading through the petsc manual  
today trying to figure out if petsc provides a matrix-free  
implementation of a Newton-Krylov-Schwarz solver. It looks like in  
terms of the Newton-Krylov part, everything can be done in a matrix- 
free setting, but I can't tell if there are routines available to  
allow for a matrix-free Additive Schwarz preconditioner, and if so,  
what needs to be provided by the user to implement it. I'm very keen  
on using petsc to provide an additive schwarz preconditioner for my   
spectral element CFD code, but I need a matrix-free implementation  
because I don't have access to the global system matrix. Does anyone  
have experience with applying matrix-free preconditioners in petsc?

Thanks,

-Aaron



P. Aaron Lott
Ph.D. Candidate
4239 Computer and Space Sciences Building
University of Maryland
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palott at ipst.umd.edu
http://www.lcv.umd.edu/~palott
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