May be this does what you are asking for https://dealii.org/current/doxygen/deal.II/classFunctions_1_1FEFieldFunction.html
best praveen > On 2 Oct 2024, at 6:29 PM, 'Xuefeng Li' via deal.II User Group > <[email protected]> wrote: > > I apologize for hitting the Send button before completing my questions. > > I realize that the evaluation of a FEM function is an expensive process due > to the fact that we'll need to determine the cell in the mesh where a point > belongs before interpolation takes place. That's why I'm just asking for the > possibility of existence of such a capability in dealii. > > Your suggestions are greatly appreciated! > > Best, > > --Xuefeng Li, (504)865-3340 <tel:%28504%29865-3340>(phone) > Department of Mathematics and Computer Science > Like floating clouds, the heart rests easy > Like flowing water, the spirit stays free > Loyola University New Orleans > New Orleans, Louisiana (504)865-2051 <tel:%28504%29865-2051>(fax) > > > On Tue, Oct 1, 2024 at 3:13 PM 'Xuefeng Li' via deal.II User Group > <[email protected] <mailto:[email protected]>> wrote: >> Hi, everyone! >> >> This is a problem related to post-processing. But I can't find a solution >> from the DataPostprocessor class. Here is the description of my problem. >> >> Solve a PDE on a 2D domain [0, 1]X[0, 1] in the x-y plane by FEM with a >> fixed mesh, say, a 16X16 mesh. The FEM solution is a Vector u=u(x, y). >> Information of u(x, y) is known if (x, y) is a grid point of the mesh. >> I need to solve for a curve x=f(y) defined by u(f(y), y)=f(y), for 0<y<1, >> where f(0) is known. >> On paper, we can solve for curve x=f(y) using Newton's method so long as >> u(x, y) and derivatives of u(x,y) are known for all (x, y) in [0, 1]X[0, 1]. >> Is it possible to evaluate solution u and its derivatives at (x, y) which is >> not a grid point of the mesh? >> Ultimately, curve x=f(y) will be approximated by f(0), f(y_1), f(y_2), ..., >> f(y_{15}), f(1). Here is a related problem. Is there a way to get a 1D >> projection of a 2D mesh in dealii? In this case, I need the projection of >> the 16X16 mesh onto the y-axis. >> >> >> -- >> 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] >> <mailto:[email protected]>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/dealii/2b65d4d8-8f79-4967-b46a-09795eec6a49n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/dealii/2b65d4d8-8f79-4967-b46a-09795eec6a49n%40googlegroups.com?utm_medium=email&utm_source=footer>. > > > -- > 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] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/dealii/CAO2HPGUDbLiXqA0NT3Je6SM4ttQgBNT4XqPLXw1WebA6NX-aZg%40mail.gmail.com > > <https://groups.google.com/d/msgid/dealii/CAO2HPGUDbLiXqA0NT3Je6SM4ttQgBNT4XqPLXw1WebA6NX-aZg%40mail.gmail.com?utm_medium=email&utm_source=footer>. -- 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]. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/BFB78A44-C53D-4F06-8EBD-93CCBDBFF1B3%40gmail.com.
