Dear all:
I am new to fenics, and I wonder if it’s possible to find the gradient w.r.t the MeshFunction?
More specified:
For a given mesh, with stored simulation result from external numerical model, we denote the f_{i} \in R be the value of the i-th mesh center. So we have no explicit expression for f but only mesh-center value.
Consider for the nonlinear poisson problem (g is known function, boundary setting is same as demo nonlinear poisson case), my question is : how we formulate the || \nabla f||^{2}, or gradient of f in fenics, with only information of the mesh and the cell center value ?
Tried solution:
[1] In demo case ‘tensor weighted poisson’, an example of the meshFunction may solve this problem. However, it reports that '‘MeshFunctionDouble can not be converted to any UFL type’ .
Thanks for anyone watched this thread.
Best regards,
Anthony