On Wed, Feb 14, 2018 at 7:11 PM, Fande Kong <[email protected]> wrote:
> On Wed, Feb 14, 2018 at 4:35 PM, Smith, Barry F. <[email protected]> > wrote: > >> >> What are you doing with the matrix? >> > > We are doing an explicit method. PDEs are discretized using a finite > element method, so there is a mass matrix. The mass matrix will be lumped, > and it becomes diagonal. We want to compute the inverse of the lumped > matrix, and also do a few of matrix-vector multiplications using the > lumped matrix or its inverse. > > The specific implementation won't make this more efficient? > I am doing this for Pylith. I think you should just do Vec operations, and pull the inverse mass matrix to the rhs. Matt > Fande, > > >> >> We don't have a diagonal matrix but it would be easy to add such a >> beast if it was performance critical, which it probably isn't. >> >> Barry >> >> >> >> >> > On Feb 14, 2018, at 3:57 PM, Fande Kong <[email protected]> wrote: >> > >> > Hi All, >> > >> > If a matrix is always diagonal, what a good way to represent the >> matrix? Still MPIAIJ, MPIBAIJ? Can we have a specific implementation for >> this? >> > >> > >> > 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/>
