$\newcommand{\Dev}{\operatorname{Dev}}$ $\newcommand{\dev}{\operatorname{dev}}$ $\newcommand{\grad}{\operatorname{grad}}$ $\newcommand{\divg}{\operatorname{div}}$ $\newcommand{\Ei}{\operatorname{Ei}}$ $\newcommand{\tr}{\operatorname{tr}}$

The ElementSet section can be used to define an element set. Element sets can be used to output data for only a subset of elements. An element set is defined through the ElementSet tag, which takes one attribute, namely name that specifies the name of the element set. For each element in the set, an elem tag is defined which takes the element id as an attribute. For example,

<ElementSet name="set01">
  <elem id="1001"/>
  <elem id="1002"/>
  <elem id="1003"/>
</ElementSet>