From d9df7f2163b6133fb3b93e726a4c50bd8f8730df Mon Sep 17 00:00:00 2001 From: Martin Kronbichler Date: Fri, 4 Sep 2009 09:32:46 +0000 Subject: [PATCH] Make formula consistent. git-svn-id: https://svn.dealii.org/trunk@19391 0785d39b-7218-0410-832d-ea1e28bc413d --- deal.II/examples/step-37/doc/intro.dox | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/deal.II/examples/step-37/doc/intro.dox b/deal.II/examples/step-37/doc/intro.dox index 99b6276b62..1ec698b4a8 100644 --- a/deal.II/examples/step-37/doc/intro.dox +++ b/deal.II/examples/step-37/doc/intro.dox @@ -109,7 +109,7 @@ In order to find out how we can write a code that performs a matrix-vector product, but does not need to store the matrix elements, let us start at looking how some finite-element related matrix $A$ is assembled: @f{eqnarray*} -A = \sum_{j=1}^{\mathrm{n,cells}} P_\mathrm{cell,{loc-glob}}^T A_\mathrm{cell} +A = \sum_{\mathrm{cell}=1}^{\mathrm{n,cells}} P_\mathrm{cell,{loc-glob}}^T A_\mathrm{cell} P_\mathrm{cell,{loc-glob}}. @f} In this formula, the matrix $P_\mathrm{cell,{loc-glob}}$ is a permutation @@ -123,7 +123,7 @@ If we are to perform a matrix-vector product, we can hence use that @f{eqnarray*} y &=& A\cdot x = \left(\sum_{\text{cell}=1}^{\mathrm{n,cells}} P_\mathrm{cell,{loc-glob}}^T A_\mathrm{cell} P_\mathrm{cell,{loc-glob}}\right) \cdot x\\ -&=& \sum_{j=1}^{\mathrm{n,cells}} P_\mathrm{cell,{loc-glob}}^T +&=& \sum_{\mathrm{cell}=1}^{\mathrm{n,cells}} P_\mathrm{cell,{loc-glob}}^T A_\mathrm{cell} x_\mathrm{cell}, @f} where $x_\mathrm{cell}$ is the values of x at the degrees of freedom -- 2.39.5