[Getfem-users] boundary conditions on nodes

[Julien Sylvestre]

Hello,
   I am trying to impose a fixed value to the z-component of 
displacement in a linear elastic problem, on a specific node, leaving 
the x- and y-components untouched. The only thing I'm currently able to 
do is something like

mfu = getfem.MeshFem(mesh, 3)
...
lower_boundary = 1+len(mesh.regions())
mesh.set_region(lower_boundary, fbot) # fbot is a list of element ids

b3 = getfem.MdBrick('dirichlet', b2, lower_boundary, mfu, 'penalized')

This doesn't do what I want:
1. I need to set the boundary condition only on one component of the 
displacement field (i.e., z, and not x or y)
2. I need to set the boundary condition only on one node; I couldn't 
find a way to create a region on a single node. Best I can do is to 
create a region on one element.
3. I want a fixed value for the specified component of the displacement 
field which is not zero, but rather some other arbitrary (fixed) number.

I was unable to get the information in a format I could understand from 
the documentation. Any help would be greatly appreciated.

Regards,
JS