Hi Prof. Wolfgang Bangerth, Thanks for your useful advice. Finally I solved this problem.
Best, Mark 2017-10-10 19:50 GMT+02:00 Wolfgang Bangerth <bange...@colostate.edu>: > On 10/10/2017 11:40 AM, Mark wrote: > >> >> I really appreciate for your quick reply. Now I do as what you said, >> using VectorTools in setup_system(). It seems working, but there is still >> one question that I always find very large values at points near >> boundaries, see attached figures. Is there a way to solve this? >> > > There are so many possible reasons for this that I can't even speculate. > Play with what you have to find out what the common theme is -- how do > things change if you try different boundary conditions, initial conditions, > right hand sides, time steps, etc. What affects the problem and what > doesn't? Can you make the problem simpler (e.g., use zero boundary values > and zero initial conditions)? Does this only happen in parallel or also if > you run the program on a single processor? > > This is sort of the mental list that I go through when debugging these > kinds of problems. I try to isolate what it is that affects the problem and > make the problem as simple as possible. Whatever is left must then at least > be related to the cause. > > Best > W. > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: bange...@colostate.edu > > www: http://www.math.colostate.edu/~bangerth/ > > -- > The deal.II project is located at http://www.dealii.org/ > For mailing list/forum options, see https://groups.google.com/d/fo > rum/dealii?hl=en > --- You received this message because you are subscribed to a topic in the > Google Groups "deal.II User Group" group. > To unsubscribe from this topic, visit https://groups.google.com/d/to > pic/dealii/5hC7jODg-7k/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > dealii+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- 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.
