Barry Smith a ?crit : > > > On Thu, 11 Jan 2007, Dimitri Lecas wrote: > > >> Barry Smith a ?crit : >> >>> Dimitri, >>> >>> No, I think this is not the correct way to look at things. Load >>> balancing the original matrix is not neccessarily a good thing for >>> doing an LU factorization (in fact it is likely just to make the LU >>> factorization have much more fill and require much more floating >>> operations). >>> Packages like SuperLU_dist and Mumps have their own internal ordering >>> routines that are specifically for getting a good ordering for doing >>> the parallel LU factorization, you should just have these solvers >>> use them (which they do automatically). >>> >>> Barry >>> >>> >>> On Thu, 11 Jan 2007, Dimitri Lecas wrote: >>> >>> >>> >> I'am no longer talking about doing LU factorization. But use iterative method >> for solving a linear system, like bicg. Like in the ex10. In this example i >> don't understand why using MatPartitioning. >> > > Please rephrase the question. Are you asking why one should do the > partition > or why one should not? Are you asking in the case where the matrix is read > from > disk or generated in a parallel program? > > I try to understand the interest to call MatPartitioning before solving the linear system with the same matrix. (Like ksp/examples/tutorials/ex10.c).
-- Dimitri Lecas