I’m working on a problem using the tIGAr and Fenics libraries. I modified the code for the biharmonic problem found at this GitHub link to compute a reference solution using B-splines of degree up to 13 (pmax=13). However, I encounter difficulties when trying to calculate the energy norm by comparing this reference solution (uref) with another solution (u) that uses a different mesh.
Here are the two approaches I’ve considered:
-
Interpolation to a Common Space: I tried interpolating both solutions into a common function space for integration, but this approach led to error.
-
Pointwise Evaluation: Also i tried point evaluation on a common set of points and then calculating the integral numerically, but this also led to the same error.
I get the same error for both approaches
*** -------------------------------------------------------------------------
*** DOLFIN encountered an error. If you are not able to resolve this issue
*** using the information listed below, you can ask for help at
*** https://fenicsproject.discourse.group/
*** Remember to include the error message listed below and, if possible,
*** include a minimal running example to reproduce the error.
*** -------------------------------------------------------------------------
*** Error: Unable to intersect cell and point.
*** Reason: Intersection is only implemented for simplex meshes.
*** Where: This error was encountered inside Cell.cpp.
*** Process: 0
*** DOLFIN version: 2019.2.0.64.dev0
*** Git changeset: ubuntu
*** -------------------------------------------------------------------------
Could someone suggest alternative methods to compute the energy norm or help troubleshoot the issues with my current approaches?