I have searched the forum, but didn’t find this topic.
I am using H1 elements in 2D and want to set my solution to have u=0 at a point in the mesh (I know this is odd but the trace of the solution is H1 on a portion of a curve in 2D and hence talking about a point value is allowed!). I could see two ways but lack a detailed knowledge of BGSpy
I thought to tag a single point and use a dirichlet=“point” when building the space, but how?
or I could use a Lagrange multiplier but don’t see how to build the constraint using SymbolicBFI.
There is a bbnd flag for H1 space, where you can prescribe point values.
You shall add the point in your mesh, and give it a flag. Then, you can set the value using
.Set(***, definedon=mesh.BBoundaries(“…”))
See attachment for a minimal example.
Another note, if you are using the new python-occ interface you can set a name for the vertex in the geometry like with any other shape object (solids, faces, edges) and then call it with the syntax Gousheng posted.
This allows for a nicer syntax for example something like this: