On Fri, Feb 28, 2014 at 1:16 PM, Xiangdong <[email protected]> wrote:
> If I assembly the matrix with MatSetValuesStencil and use KspSetOpreators > for Ksp, do I need to call KspSetDM first? > No > What is the key difference or advantage of using KspSetComputeOperators > against KspSetOperators? > With the later, you have to manage creating and preallocating the matrix. Matt > Thanks you. > > Xiangdong > > > On Tue, Feb 25, 2014 at 4:24 PM, Jed Brown <[email protected]> wrote: > >> Xiangdong <[email protected]> writes: >> > I am not clear about this. In this example, where is the format >> declaration >> > (e.g.,mpiaij) of Mat jac? Why is this mat jac always distributed in >> > a compatible way as the DM vectors? >> >> src/ksp/ksp/examples/tutorials/ex25.c calls KSPSetDM and sets functions >> to assemble the matrices and right hand side. Those objects are created >> internally (you can use -dm_mat_type sbaij if you like) and the user >> doesn't have to see them. >> > > -- 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
