From 6c168f8f28186a9f07e6cb18c4b282b2ab2ac820 Mon Sep 17 00:00:00 2001 From: Wolfgang Bangerth Date: Mon, 12 Oct 2009 23:50:44 +0000 Subject: [PATCH] Document subdomain_ids. git-svn-id: https://svn.dealii.org/trunk@19840 0785d39b-7218-0410-832d-ea1e28bc413d --- deal.II/doc/doxygen/headers/glossary.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/deal.II/doc/doxygen/headers/glossary.h b/deal.II/doc/doxygen/headers/glossary.h index e8bb780c5b..e52f080af4 100644 --- a/deal.II/doc/doxygen/headers/glossary.h +++ b/deal.II/doc/doxygen/headers/glossary.h @@ -338,6 +338,30 @@ Article{BK07, * the finite element basis functions to a single grid cell. * * + *
@anchor SubdomainId Subdomain id
+ *
Each cell of a triangulation has associated with it a property called + * the "subdomain id" that can be queried using a call like + * cell-@>subdomain_id() and that can be set for example by using + * cell-@>set_subdomain_id(13). While in principle this property + * can be used in any way application programs deem useful (it is simply an + * integer associated with each cell that can indicate whatever you want), at + * least for programs that run in parallel it usually denotes the processor a + * cell is associated with. + * + * For programs that are parallelized based on MPI but where each processor + * stores the entire triangulation (as in, for example, @ref step_18 "step-18" + * or @ref step_32 "step-32", subdomain ids are assigned to cells by + * partitioning a mesh, and each MPI process then only works on those cells it + * "owns", i.e. that belong to a subdomain that it is associated with + * (traditionally, this is the case for the subdomain id whose numerical value + * coincides with the rank of the MPI process within the MPI + * communicator). Partitioning is typically done using the + * GridTools::partition() function, but any other method can also be used to + * do this though most other ideas will likely lead to less well balanced + * numbers of degrees of freedom on the various subdomains. + *
+ * + * *
@anchor GlossSupport Support points
Support points are * by definition those points $p_i$, such that for the shape functions * $v_j$ holds $v_j(p_i) = \delta_{ij}$. Therefore, a finite element -- 2.39.5