On Fri, 22 Jun 2007, Toby Young wrote:
> > Dear Petsc-dev; > > Sorry to bring this up again. > > I am trying to fit Dirchlet boundary conditions on a matrix and retain > a symmetric matrix after this operation and have run into some difficulty. > > Let me pose my question in another way: Is there a Gaussian elimination in > the form of an LU decomposition (for example) implemented in Petsc? yes, there are a wide variety of LU solvers in PETSc both sequential and parallel. Take a look at http://www-unix.mcs.anl.gov/petsc/petsc-as/documentation/linearsolvertable.html The simpliest usage sequential is simply -ksp_type preonly -pc_type lu Barry > > It would be more useful in my case to assemble the system, apply boundary > conditions and then solve; not apply boundary conditions while assembling > the matrix as has been helpfully suggested. > > Thank you for your useful comments on this up-to-now. > > Best, > Toby > > ----- > > Toby D. Young (Adiunkt) > Department of Computational Science > Institute of Fundamental Technological Research > Polish Academy of Science > Room 206, ul. Swietokrzyska 21 > 00-049 Warszawa, POLAND > > > > > > >
