reordering PETScMatrix

Question

Hi
I want to reorder the PETScMatrix object to improve the performance of the LU solver. In my understanding, there is no method to reorder the PETScMatrix explicitly in dolfin. However, when I do a manual reordering I cannot swap the content of Mat inside the PETScMatrix with the one I created. Is there other approach which doesn't require modification of the code ?
BR

Answer 1

Good LU solvers will re-order the matrix.

DOLFIN does re-order dofs by default for data locality (primary objective) and minimising fill-in (secondary objective since an LU solver will re-order anyway).