You are using the preconditioned norm for the convergence test. You can use
KSPSetNormType(ksp, KSP_NORM_UNPRECONDITIONED) However, this will not work for all KSP types. Matt On Wed, Aug 27, 2008 at 1:23 PM, Nguyen, Hung V ERDC-ITL-MS <Hung.V.Nguyen at usace.army.mil> wrote: > All, > > We run a test case with -ksp_rtol 1.0e-15 and -ksp_max_it 50000. Then we > compute the infinity and 2 norms of |a * xsolution -b| and the results are > below. Why are these values of norms in a range 10e-8 to 10e-10 while > -ksp_rtol is set 1.0e-15? What is the PETSc convergence criteria for the > matrix solver? > > Thank you in advance, > > -Hung > >> hvnguyen:jade20% aprun -n 16 ./fw -ksp_type cg -pc_type bjacobi >> -ksp_rtol 1.0e-15 -ksp_max_it 50000 >> Time in PETSc solver = 0.7661848068237305 sec >> Computed solution - 2 norm of the residual error = >> 1.0662412498046400E-008 >> Computed solution - maximum residual error (infinity norm) = >> 5.2750692702829838E-010 >> Number of Krylov iterations = 257 >> Application 281373 resources: utime 0, stime 0 > > -- 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
