Thank you for your support. On Tuesday, April 29, 2025 at 10:32:12 AM UTC+2 [email protected] wrote:
> You could use: > > auto mask = fe.component_mask(extractor); > auto indices = DoFTools::extract_dofs(dh, mask); > > for(const auti i: indices) > if (!constraints.is_constrained(i)) > … > > > > https://www.dealii.org/current/doxygen/deal.II/namespaceDoFTools.html#a45f4d01f1c4c6337e4be6f10a81fbdab > > > Best, > Luca. > > > > On 29 Apr 2025, at 10:08, Alex <[email protected]> wrote: > > > > Dear deal.II users, > > I'm working on a monolithic coupled problem using deal.II where I'm > solving for multiple variables (e.g., displacement u, concentration c, > etc.) using a single DoFHandler and a full matrix system (i.e., not using > block structures). I use FEValuesExtractors to access individual components. > > I want to compute the error residual (e.g., L2 norm) for a specific > component only, such as displacement, by extracting only the relevant DOFs > from the global residual vector system_rhs. > > > > Here is the simplified version of what I’m doing: > > Vector<double> system_rhs; // UMFPACK > > Vector<double> error_res(dof_handler.n_dofs()); > > for (unsigned int i = 0; i < dof_handler.n_dofs(); ++i) > > if (!constraints.is_constrained(i)) > > error_res(i) = system_rhs(i); > > error_residual.norm = error_res.l2_norm(); > > > > This computes the total residual, but how can I correctly isolate and > compute the residual only for the displacement component (or any other > specific field). > > Thanks in advance! > > > > Regards, > > Alex > > > > > > -- > > 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 [email protected]. > > To view this discussion visit > https://groups.google.com/d/msgid/dealii/867b3052-f441-4d64-9621-3fd34b9c4c36n%40googlegroups.com > . > > -- 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 [email protected]. To view this discussion visit https://groups.google.com/d/msgid/dealii/047d0039-4379-45bd-ad0a-28cb666e5621n%40googlegroups.com.
