Wolfgang, > So I vote that the command line wins over what we> specify in the code. This > is what your patch did, right?
This is what I was going for. Yes and that's the PETSc philosophy. Coming from mostly a PETSc background, I found it incomprehensible to see the command line options ignored until I saw the code. But I figured the deal.II philosophy is different in this sense but nevertheless a little confusing. All the Mat, Vec, PC options are being set from command line while the KSP options are being ignored. I find this inconsistent in the deal.II call sequence. > Can I ask you to write a paragraph in the documentation of the > PETScWrappers::SolverBase class on how one could use this feature in > applications? I can definitely send you something to clarify these aspects so that you can add them to the documentation. Thanks, Vijay On Wed, Dec 14, 2011 at 11:05 PM, Wolfgang Bangerth <[email protected]> wrote: > > Vijay and Toby, > as I said, the deal.II way has traditionally been to specify everything in > the code and nothing on the command line. That has a lot to do with the fact > that I personally think that it's clearer and more reproducible, and I have > never quite understood how the PETSc behavior can reliably be controlled if > one has several nested solvers. But I accept (i) that that conflicts with > the PETSc viewpoint, and (ii) that there are useful things one can do with > PETSc by explicitly giving command line flags. So I agree that what you try > to do is useful. > > There remains the question what should happen if what we specify in the code > does not match what is passed on the command line. I don't think it is very > useful if someone goes to lengths specifying something on the command line > just to find that it is ignored (that's not a question of right or wrong; > simply of utility). So I vote that the command line wins over what we > specify in the code. This is what your patch did, right? > > Can I ask you to write a paragraph in the documentation of the > PETScWrappers::SolverBase class on how one could use this feature in > applications? > > Best & thanks to both of you! > Wolfgang > > ------------------------------------------------------------------------ > Wolfgang Bangerth email: [email protected] > www: http://www.math.tamu.edu/~bangerth/ > _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
