[staggered] Matrix block arrangement does not comply with literature standard
Papers dealing with solvers for saddlepoint problems (like the incompressible Navier-Stokes equations, example) usually define the block matrix as
M = \begin{pmatrix}
A & B^T\\
B & C
\end{pmatrix}
where A
is the block for the derivatives of the momentum balance equation residuals w.r.t velocity ("velocity block")
and C
is is the block for the derivatives of the mass balance equation residuals w.r.t pressure ("pressure block").
For incompressible fluids, C
is zero.
However, the multitype blockmatrix in Dumux for staggered problems looks like this:
M = \begin{pmatrix}
C & B^T\\
B & A
\end{pmatrix}
which causes confusion and requires special care, e.g, for the implementation of the Uzawa solver !1827 (closed)
I suggest we adapt the matrix structure such that the velocity block is on the upper left. Are there any concerns / objections?
Edited by Kilian Weishaupt