UserExpression in dolfinx

[belmont]

I think the discussion here may help

Fenicsx: use an array of data for boundary conditions

Hi. I have the following problem: Consider the following matrix in a 3d Poisson equation problem: (x_i, y_i, z_i, bc_i). The (x_i, y_i, z_i) are the bounds of a 3d mesh and bc_i is the relevant boundary conditions. So, consider now making the 3d mesh and perform a numerical calculation to find the bc_i values of each boundary point (x_i, y_i, z_i). Using those boundary conditions, I would like to use fenicsx to solve the Poisson equation in the whole mesh. I have solved this problem some year…