[petsc-users] Some questions about TS/examples/tutorials/ex13

[Matthew Knepley]

On Sat, Dec 22, 2018 at 2:26 PM Sajid Ali <sajidsyed2021 at u.northwestern.edu>
wrote:

> >   No, A(t) has five diagonals as indicated by the calls to
> MatSetValues() with five entries per row; they correspond to the usual 5 pt
> stencil in 2d.
> This might not be the right place to ask this, but I'm new to PDE's and I
> expected to find something like the matrix to be used as the one derived in
> slides 10-12 of this presentation :
> https://www.math.ust.hk/~mawang/teaching/math532/mgtut.pdf
>

Yes, that is exactly what you get. We also make that matrix in SNES ex5 if
you want to see that . Barry is just saying that a different way.

Also, I do not usually advise FD, but they are easy and memory light. I
solve this same problem using finite elements in TS ex45.

  Thanks,

     Matt


> Thanks Matt for the advice on the book. I'll have a look at it.
>


-- 
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

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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