OK Thank you very much!
Kyusik. 2017년 2월 13일 월요일 오후 1시 3분 27초 UTC+9, Wolfgang Bangerth 님의 말: > > On 02/12/2017 06:15 PM, hank...@gmail.com <javascript:> 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: bang...@colostate.edu > <javascript:> > 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.
