On 11/30/2017 05:47 PM, Bruno Turcksin wrote:
In step-36, there is an explanation on how Dirichlet boundary conditions
introduce spurious eigenvalues because some dofs are constrained. However,
there is no mention of hanging nodes. So I am wondering if I can treat them as
shown for the Dirichlet boundary, i.e, the only difference between a hanging
node and a Dirichlet is what happens in ConstraintMatrix::distribute().
Yes, I think this is correct -- you're going to have a row in the eigenvalue
equation where both matrices have an entry on the diagonal. You can set these
values to whatever you want and that's what's going to determine the size of
the spurious eigenvalue.
I also
wonder if there is a way to avoid having these spurious eigenvalues computed
They're always going to be there because we keep constrained nodes in the
linear system.
Best
W.
--
------------------------------------------------------------------------
Wolfgang Bangerth email: [email protected]
www: http://www.math.colostate.edu/~bangerth/
--
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see
https://groups.google.com/d/forum/dealii?hl=en
---
You received this message because you are subscribed to the Google Groups "deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/d/optout.
