On Dec 14, 2011, at 12:45 PM, Mark F. Adams wrote: > I have a nonlinear problem and am finding the the convergence test for the > interior PETSc linear solver is apparently testing against the norm of the > first linear solve (see appended).
No it is || r = b - Ax ||/|| b|| with a B in there if left preconditioned It has nothing to do with the "first linear solve". Each linear solve is self contained and it does not use anything from a previous linear solve to determine convergence of a later linear solve. > This is clearly not what anyone would want, Why not? Barry > is this the intended semantics? > Is there perhaps a method to reset rtol? > > Mark > > Picard iteration 0 max(resid) = 781020 > 0 KSP Residual norm 2.499264167662e+07 > 1 KSP Residual norm 6.330915810095e+06 > 2 KSP Residual norm 1.856999435466e+06 > 3 KSP Residual norm 3.967325725053e+05 > 4 KSP Residual norm 9.037332775808e+04 > 5 KSP Residual norm 1.826960320400e+04 > Linear solve converged due to CONVERGED_RTOL iterations 5 > Picard iteration 1 max(resid) = 727577 ------- Rate = 1.07345 > 0 KSP Residual norm 6.885328126772e+06 > 1 KSP Residual norm 2.150319244570e+06 > 2 KSP Residual norm 2.297759417371e+05 > 3 KSP Residual norm 3.321819214451e+04 > 4 KSP Residual norm 4.155970071625e+03 > Linear solve converged due to CONVERGED_RTOL iterations 4 > Picard iteration 2 max(resid) = 486788 ------- Rate = 1.49465 > 0 KSP Residual norm 2.987417661953e+06 > 1 KSP Residual norm 5.046119985008e+05 > 2 KSP Residual norm 3.882757664605e+04 > 3 KSP Residual norm 4.106091678345e+03 > Linear solve converged due to CONVERGED_RTOL iterations 3 > Picard iteration 3 max(resid) = 137348 ------- Rate = 3.54418 > 0 KSP Residual norm 7.285359985607e+05 > 1 KSP Residual norm 9.132700545850e+04 > 2 KSP Residual norm 6.834608381922e+03 > Linear solve converged due to CONVERGED_RTOL iterations 2 > Picard iteration 4 max(resid) = 25082.7 ------- Rate = 5.47582 > 0 KSP Residual norm 1.207523847817e+05 > 1 KSP Residual norm 1.286174706329e+04 > Linear solve converged due to CONVERGED_RTOL iterations 1 > Picard iteration 5 max(resid) = 5723.21 ------- Rate = 4.38264 > 0 KSP Residual norm 2.211945822133e+04 > Linear solve converged due to CONVERGED_RTOL iterations 0 >