On 02/12/2017 06:15 PM, hanks0...@gmail.com wrote:
Do you mean that it is right way to get second derivatives but it could not be
continuous?
Yes, you are using the correct way of computing something that is of
questionable usefulness. As I mentioned, this is because for finite elements,
the function is continuous, the derivative is discontinuous, and then the
second derivative is questionable.
Think of the situation just in 1d where the solution is a piecewise linear
function. Imagine how the derivative looks (piecewise constant) and how the
second derivative would look like (a set of delta functions).
I also attach the plot for d^2(solution)/dx^2 that look weird to me...
I think it is plausible. It is at least not obviously wrong in my mind.
Best
W.
--
------------------------------------------------------------------------
Wolfgang Bangerth email: bange...@colostate.edu
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 dealii+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
