Vaibhav, 2016-11-01 4:24 GMT-04:00 Vaibhav Palkar <vaibhav_pal...@iitgn.ac.in>: > To quickly restate, I'm solving a reaction-diffusion problem using a > framework much like Step-52. My equations are stiff and hence I'm using > implicit methods for solving the resulting ODEs. Unfortunately, it seems > that even implicit methods are not good enough for this stiff problem, the > simulation doesn't converge for time steps as low as 0.001! I can definitely > try reducing the time step further but, I was wondering if there is any > other efficient way to deal with this issue within the dealii framework? Have you tried to increase the number of Newton iterations? The Newton solver is pretty basic (it doesn't do any line search) so it might be the reason it doesn't work. If you send me a short program that reproduces the problem, I can try to make it work. However, I am pretty busy in November, so it may take a month or so before I can work on it.
> I have tried MATLAB's ODE15s and it works good for this problem but, I > couldn't find an equivalent C++ implementation. I know about GSL's (GNU > Scientific Library) ODE suite and I think I will use that as it includes > some advanced ODE solving algorithms. I was wondering if anyone knows about > similar or better implementations? A very popular package for ODE solving is sundials http://computation.llnl.gov/projects/sundials. That's what I would use. > On a similar note, are there plans to implement more ODE solving methods in > upcoming releases of dealii? I don't think that there are any plans to implement more methods in the short term. 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. For more options, visit https://groups.google.com/d/optout.
