Hi! To control my mesh refinement, I want to check each cell and if it is not small enough in relation to the gradient, refine further.
This is how I would compute the values of the gradient:
VFS = VectorFunctionSpace(mesh, 'Lagrange', 1)
uproj = project(grad(u), VFS)
uproj_val = uproj.vector().array()
How can these values be related to the cellsizes?