Perfect, Thank you a lot,
Sonia Ph.D. Student Group of Prof. Rolf Krause Institute of Computational Science Università della Svizzera italiana Center for Computation Medicine in Cardiology Via Giuseppe Buffi, 13 CH-6900 Lugano Switzerland Email: poz...@usi.ch <mailto:poz...@usi.ch> Phone: +41 58 666 4972 > On 14 Mar 2018, at 16:00, Matthew Knepley <knep...@gmail.com> wrote: > > On Wed, Mar 14, 2018 at 11:21 PM, Sonia Pozzi <sonia.po...@usi.ch > <mailto:sonia.po...@usi.ch>> wrote: > Dear Barry, > > thank you for the answer. That helped a lot. Just a second curiosity. > I’m setting A00 to be solved with preonly+lu. I obtain the following > ksp_0 KSPGetTotalIterations: 26 > ksp_1 KSPGetTotalIterations: 22 > Residual ksp_0: 0 Reason ksp_0: 4 > Solution ksp_0 : Convergence in 1 iterations. > Residual ksp_1: 5.23074e-14 Reason ksp_1: 2 > Solution ksp_1 : Convergence in 11 iterations. > Initial system linear residual: 9.904804e-09 > > To me is clear that kps_0 iterations number is equal to 22*1+2*2. > But why is the iterations number for the schur complement multiplied by two? > I’m giving the mass matrix as a preconditioner for the schur complement. > > Possible cause: > > The preconditioner is applied once before the solve happens in order to > compute the preconditioned initial residual. Then > if you do just one iterate in the solve, you would have two applications of > the preconditioner. > > Thanks, > > Matt > > Sonia > > Ph.D. Student > Group of Prof. Rolf Krause > Institute of Computational Science > Università della Svizzera italiana > Center for Computation Medicine in Cardiology > Via Giuseppe Buffi, 13 > <https://maps.google.com/?q=Via+Giuseppe+Buffi,+13+CH-6900+Lugano+Switzerland&entry=gmail&source=g> > CH-6900 Lugano > <https://maps.google.com/?q=Via+Giuseppe+Buffi,+13+CH-6900+Lugano+Switzerland&entry=gmail&source=g> > Switzerland > <https://maps.google.com/?q=Via+Giuseppe+Buffi,+13+CH-6900+Lugano+Switzerland&entry=gmail&source=g> > > Email: poz...@usi.ch <mailto:poz...@usi.ch> > Phone: +41 58 666 4972 <tel:+41%2058%20666%2049%2072> >> On 14 Mar 2018, at 14:52, Smith, Barry F. <bsm...@mcs.anl.gov >> <mailto:bsm...@mcs.anl.gov>> wrote: >> >> KSPGetIterationNumber > > > > > -- > 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 > > https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
