Bruce, The p_local_solution vector is filled with values as the result of solving > a linear equation, p_local_rho is filled with values by looping over > individual elements and assigning values calculated from other quantities. > Part of the reason the p_local_rho vector doesn't have ghost nodes is that > you can't access individual elements for a ghosted vector. > You can't write to a ghosted vector, but you can read from it. Is this what you mean?
The DataOut object appears to only handle ghosted vectors. It also appears > that you need to call compress on non-ghosted vectors (this was determined > empirically based on error messages). > Yes, for proper output you should use ghosted vectors that store the solution on all the dofs of locally owned cells. If you modify a parallel vector you have to call compress as mentioned in step-40 [1] for example. Would you want to have this information at some different place as well. If yes, where? > The vecScale function is just designed to multiply all values of an > un-ghosted vector by a constant. > You could also use operator*= [2] for this. If you don't change the values of the vectors using vecScale then the data > for "Phi" and "Rho" appears smooth (but the scale is unwieldy). If you > change the values of the vectors using vecScale, then "Phi" looks okay but > "Rho" appears to have unscaled values at locations that look like they are > at processor boundaries. I'm puzzled about how this is happening, since my > understanding is that a data exchange happens when you do the assignment > rho = p_local_rho. The vecScale function only operates on un-ghosted > vectors, but is it possible that it is missing some values somewhere? > This sounds weird as you do the exact same thing to (rho, p_local_rho) and (p_local_solution, phi). So you observe that p_local_solution looks wrong as well? Do you have a minimal working example showing this problem? Best, Daniel [1] https://dealii.org/8.4.0/doxygen/deal.II/step_40.html#LaplaceProblemassemble_system [2] https://www.dealii.org/8.4.0/doxygen/deal.II/classPETScWrappers_1_1VectorBase.html#a37900779c6049418c39bacc1d44f4260 -- 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.
