[petsc-users] Solutions different after program restart

[Niceno Bojan]

Dear Jed,


> > Residual norm obtained from a call to "KSPGetResidualNorm(ksp, &rnorm);",
> > gives:
> >
> > - First run: 1.98077e-02
> > - Second run: 2.61329e-02
> >
> > The tolerances I request from KSP's gmres solver are:
> >
> > - Linear solver relative tolerance = 0.001;
> > - Linear solver absolute tolerance = 1.0e-5;

> Is the initial residual about 30?

I don't know.  Is there a way to find out?


> In that case, check that the system being solved is identical. You can save
> it with -ksp_view_binary. Load it with
> src/ksp/ksp/examples/tutorials/ex10.c as an independent test. Also be sure
> to use the same initial guess.

Thanks.  I was checking norms of matrix "A" and "x" and "b" vectors (2nd order) and they ARE the same before and after restart.  Does the same norm ensure the matrices and and vectors are the same?  

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