[petsc-users] Use boomeramg to solve system of PDEs

[Mark F. Adams]

I recommend the Trottenberg "Multrigrid" book.

This will not work unscaled, the off diagonal terms as large as the diagonal, its is very unsymmetric.  The time term on the diagonal might save you but that is fragile.

I'm sure someone has worked through how to attack this as a block system but I can see that its almost lower triangular so block Gauss-Seidel iterations looks like a good place to start.

Mark

On Feb 3, 2012, at 8:25 AM, Thomas Witkowski wrote:

> Is there (good) literature that provides more information about solving systems of PDE with geometric/algebraic multigrid?
> 
> Am 03.02.2012 14:11, schrieb Jed Brown:
>> 
>> On Fri, Feb 3, 2012 at 16:03, Thomas Witkowski <thomas.witkowski at tu-dresden.de> wrote:
>> The system writes
>> 
>> L 0 M
>> M L 0
>> L M L
>> 
>> With L = discrete laplace, M = mass matrix, 0 = empty matrix
>> 
>> Hmm, what are the relative scales of these equations?
>>  
>> 
>> 
>> AMG is more delicate and generally less robust for systems.
>> Is this different with geometric multigrid?
>> 
>> Null space issues are usually easier with geometric, but constructing low energy interpolants can require custom work.
> 

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