Setting parameters in the Customed Newton Solver

1

Here, we can find an example of a customized newton solver that is recommended by Nate. The newton solver works quite well after running the example. However, in general, I am not sure how to set the parameters in this customized newton solver as we usually did in the NonlinearVariationalSolver like the following:

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I find that to change the precondtioner to hypre_amg, we do can the following:
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However, changing to ilu as precondtioner is slightly different (commented out). There has to be a general rule that I can follow but I cannot find the right documentation for this, hence not sure how to properly set all these parameters.

Any ideas are appreciated. Thank you!

2

Just an update here. I found one solution.
Here is a link to several PETScoptions that we can set in the linear solver of Newton solver, i.e. the KSP solver.
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To set the parameters of the Newton iteration, we can do it outside Newton Solver class, like the following:

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Please let me know if there are any other better ways or better Customized Newton solvers that I can use. I guess the advantage of this Customized Newton Solver over the usual NonLinearVariationalSolver is that we can set_operator for the linear solver inside the Newton Solver. The parameters setting are almost the same as in the NonLinearVariationalSolver.