From: bangerth Date: Mon, 21 Mar 2011 16:51:59 +0000 (+0000) Subject: Add documentation. X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d10f90779e56f350638d45936d74e53b3227e4cc;p=dealii-svn.git Add documentation. git-svn-id: https://svn.dealii.org/trunk@23487 0785d39b-7218-0410-832d-ea1e28bc413d --- diff --git a/deal.II/doc/doxygen/headers/vector_valued.h b/deal.II/doc/doxygen/headers/vector_valued.h index 662bab6719..9b20ff7702 100644 --- a/deal.II/doc/doxygen/headers/vector_valued.h +++ b/deal.II/doc/doxygen/headers/vector_valued.h @@ -375,6 +375,20 @@ * step-22, * step-31 and several other programs. * + * @note In the current context, when we talk about a vector (for example in + * extracting the velocity components above), we mean the word in the sense + * physics uses it: it has spacedim components that behave in + * specific ways under coordinate system transformations. Examples include + * velocity or displacement fields. This is opposed to how mathematics uses + * the word "vector" (and how we use this word in other contexts in the + * library, for example in the Vector class), where it really stands for a + * collection of numbers. An example of this latter use of the word could be + * the set of concentrations of chemical species in a flame; however, these + * are really just a collection of scalar variables, since they do not change + * if the coordinate system is rotated, unlike the components of a velocity + * vector, and consequently, this FEValuesExtractors::Vector class should not + * be used for this case. + * * * @anchor VVAlternative *

An alternative approach