Thanks for your answer, whereas being 'sad' to me! Do you have any idea
how the structure FE code geared toward HPC deals with their Lagrange
multipliers for their BCs? Do they 'accept' that cost?
To my understanding, I didn't know the Sherman-Morrison formula, and I
am not sure to see how it applies to my case... Could you please help me
on that?
Many thanks,
Olivier
I am not sure you can get around this cost. In this case, it reduces
to the well-known
Sherman-Morrison formula
(https://en.wikipedia.org/wiki/Sherman%E2%80%93Morrison_formula),
which Woodbury generalized. It seems to have the same number of solves.
