>>> *That might not easily be possible with our PETSc interfaces.*
*PETSc has the concept of MatShell, which is in essence what
deal.II'sLinearOperator is: A class that implements a matrix-vector
operation,without giving access to individual matrix elements. You could
trywhether you can
Hi, Daniel
Thank you very much for your valuable advice and I will try with that.
在2021年8月26日星期四 UTC+8 上午5:17:20 写道：
> Toddy,
>
> I would start with thinking about the time discretization scheme you want
> to use and in particular which terms you want to treat explicitly and which
>
Toddy,
I would start with thinking about the time discretization scheme you want
to use and in particular which terms you want to treat explicitly and which
implicitly.
After you have done that, you might still end up with a nonlinear problem
in which case you should have a look at
On 8/25/21 11:53 AM, Anton Ermakov wrote:
I I¯ A 0 ¯I *eigenvalue + I¯ 0 B ¯ I I * eigenvector =0
I I_ 0 0 _I I_ C D _I I
¯ ¯
where eigenvector consists of a vector
Dear Deal.II community,
I am working on implementing a vector eigenproblem in deal.ii, starting
from the step-36 example. The question I am studying is the normal
oscillation of a fluid planet. The eigenproblem is of this type:
_
Dear Deal.II community,
I'm getting trouble in constructing system matrix of a complex PDE. My PDE
is a time-dependent equation, and in simplicity it seems like
[image: screenshot.png]
U is the variable, t denotes the time. D, alpha, beta are constant. So
could you please give me some advice
