Problem in convergence after upgrade to petsc 3.0.0

Randall Mackie rlmackie862 at
Fri Jan 30 20:01:33 CST 2009

I just downloaded and compiled Petsc 3.0.0-p2, and after making some changes
in my code to specify the correct location of the include files, finally
got everything to compile okay.

Now, I'm trying to run my test problem, and it's not converging. When I say
not converging, the first line (with ksp_monitor_true_residual) shows that
the true and preconditioned residuals are the same as before, but immediately
thereafter, the preconditioned residual fails to go below 1e-8 whereas before
it quickly went down to 1e-15.

The options in my command file are:

-ksp_type bcgsl
-pc_type bjacobi
-sub_pc_type ilu
-sub_pc_factor_levels 3
-sub_pc_factor_fill 6

The only thing I see in the Change notes are that the ILU defaults to shifting
so that it's p.d. but I don't see an easy way to turn this off by the command
line to see if that's the problem. I tried to do it in my program, but it's unclear
if I did that correctly.

Any suggestions?

Thanks, Randy

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