From 907b844cefd0147f2568c616fa57375780e20736 Mon Sep 17 00:00:00 2001 From: Martin Kronbichler Date: Tue, 23 May 2023 18:07:24 +0200 Subject: [PATCH] step-14 tutorial: Fix typo in introduction --- examples/step-14/doc/intro.dox | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/examples/step-14/doc/intro.dox b/examples/step-14/doc/intro.dox index ae77127acd..308d8d4db2 100644 --- a/examples/step-14/doc/intro.dox +++ b/examples/step-14/doc/intro.dox @@ -46,7 +46,7 @@ value $J(u_h)$ is within certain limits of the exact value $J(u)$, i.e. we want to bound the error with respect to this functional, $J(u)-J(u_h)$. For simplicity of exposition, we henceforth assume that both the quantity of -interest $J$, as well as the equation are linear, and we will in particular +interest $J$ as well as the equation are linear, and we will in particular show the derivation for the Laplace equation with homogeneous Dirichlet boundary conditions, although the concept is much more general. For this general case, we refer to the references listed above. The goal is to obtain @@ -88,8 +88,8 @@ integrate by parts on each of them: \sum_K (-\Delta (u-u_h), z-\varphi_h)_K + (\partial_n (u-u_h), z-z_h)_{\partial K}. @f} -Next we use that $-\Delta u=f$, and that for solutions of the Laplace -equation, the solution is smooth enough that $\partial_n u$ is +Next we use that $-\Delta u=f$, and that +the solution of the Laplace equation is smooth enough that $\partial_n u$ is continuous almost everywhere -- so the terms involving $\partial_n u$ on one cell cancels with that on its neighbor, where the normal vector has the opposite sign. (The same is not true for $\partial_n u_h$, though.) @@ -116,8 +116,8 @@ with the neighbor cell $K'$, to obtain - \frac 12 (\partial_n u_h|_K + \partial_{n'} u_h|_{K'}, z-\varphi_h)_{\partial K\backslash \partial\Omega}. @f} -Using that for the normal vectors on adjacent cells we have $n'=-n$, we define the jump of the -normal derivative by +Using that for the normal vectors on adjacent cells we have $n'=-n$, we define +the jump of the normal derivative by @f[ [\partial_n u_h] \dealcoloneq \partial_n u_h|_K + \partial_{n'} u_h|_{K'} = @@ -139,9 +139,9 @@ element discretization with respect to arbitrary (linear) functionals $J(\cdot)$. Its structure is a weighted form of a residual estimator, as both $f+\Delta u_h$ and $[\partial_n u_h]$ are cell and edge residuals that vanish on the exact solution, and $z-I_h z$ are weights indicating how important the -residuals on a certain cell is for the evaluation of the given functional. +residual on a certain cell is for the evaluation of the given functional. Furthermore, it is a cell-wise quantity, so we can use it as a mesh refinement -criterion. The question, is: how to evaluate it? After all, the evaluation +criterion. The question is: how to evaluate it? After all, the evaluation requires knowledge of the dual solution $z$, which carries the information about the quantity we want to know to best accuracy. @@ -259,5 +259,5 @@ example programs, regarding the mathematical complexity, as well as the simplicity to add extensions. If you use this program as a basis for your own programs, we would kindly like to ask you to state this fact and the name of the author of the example program, Wolfgang Bangerth, in publications that -arise from that, of your program consists in a considerable part of the +arise from that, if your program consists in a considerable part of the example program. -- 2.39.5