With PETSc, you will have to specify that you are using a non-zero initial guess using
http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/KSP/KSPSetInitialGuessNonzero.html KSPSetInitialGuessNonzero(ksp, PETSC_TRUE) If this is not set, it will reset the vector to zero and sure, then there is nothing to be gained. I haven't looked if a similar behavior exists for the Deal.II internal solvers. Vijay On Thu, May 10, 2012 at 1:51 PM, Wolfgang Bangerth <[email protected]> wrote: > >> I was hoping this would happen internally since it doesn't make sense >> for the linear solver to start the iteration cycle with a zero guess >> when one could re-use the computed solution on a coarser mesh to get >> an estimate of the solution on the finer grid. > > > I tried this a long time ago and it turns out that it doesn't make much of a > difference to start CG with the interpolated previous solution. > > W. > > ------------------------------------------------------------------------ > Wolfgang Bangerth email: [email protected] > www: http://www.math.tamu.edu/~bangerth/ > > _______________________________________________ > dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
