Cannot create 1d mesh

[dokken]

The point is:

1. You haven’t stored your facet markers to file. See for instance: How to read a physical object from a xdmf file - #7 by dokken where I already showed you this.

@mekong

For a 1d mesh, this becomes
\int_0^L dx \partial_x v = v|^L_0∫L0dx∂xv=v|L0\int_0^L dx \partial_x v = v|^L_0, how may I write this in Fenics? Is it (v * ds_r) - (v * ds_l)?

Thank you

The notation doesn’t change in DOLFIN for a 1D mesh. Just use the same notation (or alternatively what you have written as an option).