]> https://gitweb.dealii.org/ - dealii.git/commitdiff
Add documentation.
authorWolfgang Bangerth <bangerth@math.tamu.edu>
Mon, 21 Mar 2011 16:47:31 +0000 (16:47 +0000)
committerWolfgang Bangerth <bangerth@math.tamu.edu>
Mon, 21 Mar 2011 16:47:31 +0000 (16:47 +0000)
git-svn-id: https://svn.dealii.org/trunk@23486 0785d39b-7218-0410-832d-ea1e28bc413d

deal.II/include/deal.II/fe/fe_values.h

index c5e0b52aad89a09f1d27a31beda3b0316f19a26a..1fcf713befa1b74223291806559ec924c090fb1f 100644 (file)
@@ -148,9 +148,9 @@ namespace FEValuesExtractors
 
                                   /**
                                    * Extractor for a vector of
-                                   * <code>dim</code> components of a
+                                   * <code>spacedim</code> components of a
                                    * vector-valued element. The value of
-                                   * <code>dim</code> is defined by the
+                                   * <code>spacedim</code> is defined by the
                                    * FEValues object the extractor is applied
                                    * to.
                                    *
@@ -160,6 +160,29 @@ namespace FEValuesExtractors
                                    * FEValuesExtractors and in the @ref
                                    * vector_valued module.
                                    *
+                                   * Note that in the current context, a
+                                   * vector is meant in the sense physics
+                                   * uses it: it has <code>spacedim</code>
+                                   * 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 class should not be used for this
+                                   * context.
+                                   *
                                    * @ingroup feaccess vector_valued
                                    */
   struct Vector
@@ -499,11 +522,34 @@ namespace FEValuesViews
 
                                   /**
                                    * A class representing a view to a set of
-                                   * <code>dim</code> components forming a
+                                   * <code>spacedim</code> components forming a
                                    * vector part of a vector-valued finite
                                    * element. Views are discussed in the
                                    * @ref vector_valued module.
                                    *
+                                   * Note that in the current context, a
+                                   * vector is meant in the sense physics
+                                   * uses it: it has <code>spacedim</code>
+                                   * 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 class should not be used for this
+                                   * context.
+                                   *
                                    * @ingroup feaccess vector_valued
                                    */
   template <int dim, int spacedim=dim>

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