Dear Barry, Thanks for your explanation!
R Quoting Barry Smith <bsmith at mcs.anl.gov>: > > The linear solver did not fail to converge. It says it converged. > > The nonlinear solver failed because the line search failed, not > the linear solver. This is common when the changes are tiny, tiny > like they are here. You cannot expect that corrections that are the > same size as the round error to improve the nonlinear system. That > is your initial guess is so small you cannot do any better. > > I will change the LS in the message to line_search for clarity in > petsc-dev > > > > Barry > > On Sep 10, 2010, at 9:54 AM, Rebecca Xuefei Yuan wrote: > >> Dear all, >> >> I have the convergence history as >> >> >> >> 0 SNES Function norm 1.930639214656e-14 >> 0 KSP Residual norm 1.930639214656e-14 >> 1 KSP Residual norm 1.897969082784e-14 >> 2 KSP Residual norm 1.890943705731e-14 >> 3 KSP Residual norm 1.890499250642e-14 >> 4 KSP Residual norm 1.882719263807e-14 >> 5 KSP Residual norm 1.881639616800e-14 >> 6 KSP Residual norm 1.881624492545e-14 >> 7 KSP Residual norm 1.876497311488e-14 >> 8 KSP Residual norm 1.864714377471e-14 >> 9 KSP Residual norm 1.861061216430e-14 >> 10 KSP Residual norm 1.856993815540e-14 >> 11 KSP Residual norm 1.856245191617e-14 >> 12 KSP Residual norm 1.855993722295e-14 >> 13 KSP Residual norm 1.855756795426e-14 >> 14 KSP Residual norm 1.855542358114e-14 >> 15 KSP Residual norm 1.855188622531e-14 >> 16 KSP Residual norm 1.854906019037e-14 >> 17 KSP Residual norm 1.851397858397e-14 >> 18 KSP Residual norm 1.851152033377e-14 >> 19 KSP Residual norm 1.845662066987e-14 >> 20 KSP Residual norm 1.810881990601e-14 >> 21 KSP Residual norm 9.715701270773e-15 >> 22 KSP Residual norm 2.134473951854e-15 >> Linear solve converged due to CONVERGED_RTOL iterations 22 >> Nonlinear solve did not converge due to DIVERGED_LS_FAILURE >> >> Why the linear solver is failed? >> >> Thanks a lot! >> >> >> >> >> >> Rebecca Xuefei YUAN >> Department of Applied Physics and Applied Mathematics >> Columbia University >> Tel:917-399-8032 >> www.columbia.edu/~xy2102 >> > > > Rebecca Xuefei YUAN Department of Applied Physics and Applied Mathematics Columbia University Tel:917-399-8032 www.columbia.edu/~xy2102
