James, On Tuesday, October 13, 2020 at 8:39:42 PM UTC-4 James Gorman wrote:
> > I am, however, at a loss for how to efficiently make it so that Step-44 > (or any other script) will automatically decrease a time-step. The only > idea I had at the moment was to use a ``for'' loop and run a certain number > of iterations, and each time the solution did not converge would be to > multiply the time-step by some fraction. However, I am not sure this > solution would work well with my previous solution > That's the right idea. You want to be careful that you don't end up reducing your time step too much though. Otherwise you could end up with a time step that is effectively zero. > Has anyone done this before, or have thoughts on how one might modify > Step-44 to automatically increase and decrease based on the number of > iterations required for Newton-Raphson convergence or divergence? Thank you > for your help. > What you are trying to do is similar to what embedded methods do but instead of using the error you are using the number of Newton iterations. Here is how embedded methods work in deal.II https://github.com/dealii/dealii/blob/master/include/deal.II/base/time_stepping.templates.h#L770-L857 Best, Bruno -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/c7cdb4aa-62d9-4741-b8f1-851b8680289an%40googlegroups.com.