[petsc-users] Preconditioning in matrix free SNES

Jed Brown jed at 59A2.org
Sat Feb 5 08:24:11 CST 2011

I applaud your attention to detail if you worked out that Jacobian without
AD. There has been some success preconditioning high order methods with
nonlinear reconstruction using a matrix assembled with first order upwinding
(sparser and less messy to work out). I works be interested to hear if that
works well for you.

On Feb 4, 2011 8:17 PM, "Travis C. Fisher" <travis.fisher at nasa.gov> wrote:


Thanks for the response. I think I have resolved this particular issue. My
jacobian was incorrect. I use generalized coordinates and
I missed a scaling factor. I found this by generating the matrix finite
difference coloring and calculating
the approximate jacobian, which was much easier than I originally
anticipated. The jacobian I am trying to create is exact for convective
terms based on the numerical methods (ESWENO finite difference schemes).

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