On Tue, Oct 10, 2017 at 10:36 AM, Kong, Fande <fande.k...@inl.gov> wrote:
> Hi Developers, > > I am trying to use the native LU in PETSc to compute a matrix (arising > from a fluid-structure interaction problem). I encounter a zero pivot. The > matrix gives the wrong Newton direction when using "-pc_factor_shift_type > nonzero -pc_factor_shift_amount 1". I hence guess the matrix is > singular. > > Any easy way to detect if or not the matrix is singular?? > That is the easiest way, namely having LU fail. You can catch the failure and do something useful. Matt > Fande, > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
