Merge pull request #3645 from henrikt-ma/absoluteValue-default

Make absoluteValue inferred by default

Author: HansOlsson

chapters/annotations.tex

@@ -1529,12 +1529,18 @@ \section{Graphical User Interface}\label{annotations-for-the-graphical-user-inte
 \end{lstlisting}\end{synopsis}
 \begin{semantics}
 Allowed for simple types and components of a simple types.
-If \lstinline!false!, then the variable defines a relative quantity, and if \lstinline!true! an absolute quantity.
+If \lstinline!false!, then the component defines a relative quantity, and if \lstinline!true! an absolute quantity.
+When converting between units (e.g., in plots and where parameters are edited), the unit offset must be ignored for relative quantities.
+The annotation is inherited in the sense that when \lstinline!absoluteValue! is defined for a simple type, it also applies derived classes.
+When \lstinline!absoluteValue! is defined for a simple type, it also applies to components declared with the type.
+
+When \lstinline!absoluteValue! of a component is not determined by an annotation (possibly through inheritance), the \lstinline!absoluteValue! status may be inferred by the tool.
+If the \lstinline!absoluteValue! of a component is neither determined by annotation nor inference, unit conversions that would differ depending on \lstinline!absoluteValue! cannot be performed.
 
 \begin{nonnormative}
-When converting between units (in the user-interface for plotting and entering parameters), the unit offset must be ignored for a variable defined with annotation \lstinline!absoluteValue = false!.
-This annotation is used in the Modelica Standard Library, for example in \lstinline!Modelica.Units.SI! for the type definition \lstinline!TemperatureDifference!.
-For most types there is no unit offset and the annotation is not needed for them.
+For most quantities there are no units with offset, and the annotation is not needed.
+For a component where unit conversions involving offsets could be of interest (mainly temperatures), ensuring that \lstinline!absoluteValue! is determined by an annotation (typically by means of using a type where it has been specified) may reduce impact of quality-of-implementation in tool ability to infer \lstinline!absoluteValue!.
+Example applications of this annotation can be found among the type definitions in the \lstinline!Modelica.Units! package of the Modelica Standard Library, such as \lstinline!TemperatureDifference!.
 \end{nonnormative}
 \end{semantics}
 \end{annotationdefinition}