[petsc-users] (no subject)

Matthew Knepley knepley at gmail.com
Fri Feb 21 19:48:40 CST 2014

On Fri, Feb 21, 2014 at 12:34 PM, Chung-Kan Huang <ckhuangf at gmail.com>wrote:

> Hello,
> In my application I like to use
> PetscErrorCode  KSPSetOperators(KSP ksp,Mat Amat,Mat Pmat,MatStructure
> flag)
> and have Pmat different from Amat
> if Amat = L + D + U
> then Pmat  = Amat  - L* - U* + rowsum(L* + U*)
> where L* and U* is a portion of L and U and rowsum(L* + U*) will add into D
> I know I can explicitly construct Pmat step-by-step but wonder what will
> be the most easy way to do this in PETSC?

It sounds like you should just use MatSetValues() since we have no idea
what L* and U* are.


> Thanks,
> Kan

What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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