a question about tolerance

[Ryan Yan]

Hi All,
I have a question about -ksp_rtol.

when I run my application with -ksp_rtol 1e-2, I got the convergence history
as the follows.

 0 KSP preconditioned resid norm 2.129970351489e+03 true resid norm
1.040507012955e-02 ||Ae||/||Ax|| 1.000000000000e+00
  1 KSP preconditioned resid norm 3.979448548799e+01 true resid norm
7.588481061015e-03 ||Ae||/||Ax|| 7.293060946766e-01
  2 KSP preconditioned resid norm 2.177668520277e+01 true resid norm
6.608917234932e-03 ||Ae||/||Ax|| 6.351631610983e-01
  3 KSP preconditioned resid norm 2.519310038389e+00 true resid norm
4.725744786785e-03 ||Ae||/||Ax|| 4.541771201874e-01
KSP Object:
  type: gmres
...

when I run my application with -ksp_rtol 1e-3, I got the convergence history
as the follows.
  0 KSP preconditioned resid norm 2.129970351489e+03 true resid norm
1.040507012955e-02 ||Ae||/||Ax|| 1.000000000000e+00
  1 KSP preconditioned resid norm 3.979448548799e+01 true resid norm
7.588481061015e-03 ||Ae||/||Ax|| 7.293060946766e-01
  2 KSP preconditioned resid norm 2.177668520277e+01 true resid norm
6.608917234932e-03 ||Ae||/||Ax|| 6.351631610983e-01
  3 KSP preconditioned resid norm 2.519310038389e+00 true resid norm
4.725744786785e-03 ||Ae||/||Ax|| 4.541771201874e-01
  4 KSP preconditioned resid norm 5.945684204702e-01 true resid norm
2.622092992533e-03 ||Ae||/||Ax|| 2.520014723483e-01
KSP Object:
  type: gmres

How can I explain the relative tolerance is function correctly? as you can
see from the term ||Ae||/||Ax||, neither of my testruns seems to stop at the
right place(should be 10^(-2), 10^(-3) respectively).

Thanks a lot.

Yan
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