From 5e559fe8f9b6a4272f10dbb892efd88c1b9755d6 Mon Sep 17 00:00:00 2001 From: Wolfgang Bangerth Date: Tue, 18 May 2004 23:23:19 +0000 Subject: [PATCH] Add important comment. git-svn-id: https://svn.dealii.org/trunk@9262 0785d39b-7218-0410-832d-ea1e28bc413d --- deal.II/deal.II/include/dofs/dof_handler.h | 26 ++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/deal.II/deal.II/include/dofs/dof_handler.h b/deal.II/deal.II/include/dofs/dof_handler.h index 44ae5b907d..6a87bc382f 100644 --- a/deal.II/deal.II/include/dofs/dof_handler.h +++ b/deal.II/deal.II/include/dofs/dof_handler.h @@ -372,6 +372,32 @@ class DoFHandler : public Subscriptor, * picture drawing. An example can be * found in the implementation of this * function. + * + * Note that this function is + * most often used to determine + * the maximal row length for + * sparsity + * patterns. Unfortunately, the + * while the estimates returned + * by this function are rather + * accurate in 1d and 2d, they + * are often significantly too + * high in 3d, leading the + * SparsityPattern class to + * allocate much too much memory + * in some cases. Unless someone + * comes around to improving the + * present function for 3d, there + * is not very much one can do + * about these cases. The typical + * way to work around this + * problem is to use an + * intermediate compressed + * sparsity pattern that only + * allocated memory on + * demand. Refer to the step-11 + * example program on how to do + * this. */ unsigned int max_couplings_between_dofs () const; -- 2.39.5