From b0c239ad1c50d3e7dc644c10ec25eaba42e5ab52 Mon Sep 17 00:00:00 2001 From: Henrik Tidefelt Date: Thu, 2 Apr 2026 17:14:48 +0200 Subject: [PATCH] Non-normatively give rough explanation of 'tunable parameter' --- chapters/classes.tex | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/chapters/classes.tex b/chapters/classes.tex index 286c1e8a7..7a5a73530 100644 --- a/chapters/classes.tex +++ b/chapters/classes.tex @@ -426,7 +426,7 @@ \section{Component Variability}\label{component-variability} A variable \lstinline!np! declared with the \lstinline!parameter!\indexinline{parameter} prefix, is called a \firstuse[parameter!non-evaluable]{non-evaluable parameter variable}\index{component variability!non-evaluable parameter} unless it is an evaluable parameter. It is also simply called a \firstuse[---]{non-evaluable parameter}. It does not change during transient analysis, with a value determined by the initialization problem. - For further details, see \ref{parameters}. + For further details and tool-specific exceptions, see \ref{parameters}. \item A \firstuse[discrete-time!variable]{discrete-time variable}\index{component variability!discrete-time} \lstinline!vd! is a variable that is discrete-valued (that is, not of \lstinline!Real! type) or assigned in a \lstinline!when!-clause. The \lstinline!discrete!\indexinline{discrete} prefix may be used to clarify that a variable is discrete-time. @@ -583,6 +583,15 @@ \subsection{Parameters}\label{parameters} Here, a good error message for the variability error can include the information that the reason for \lstinline!n! being a non-evaluable parameter is that it has a dependency on the non-evaluable parameter \lstinline!b!. \end{nonnormative} +\begin{nonnormative} +A variant of parameter component variability which is in use, but with tool-dependent meaning, is \firstuse{tunable parameter}. +Despite the rule that a parameter (evaluable or not) does not change during transient analysis, the idea is that some parameters still would be possible to change at events during transient analysis. +When a tool identifies such a parameter, it is often referred to as a \emph{tunable parameter}. +Both evaluable and non-evaluable parameters can be tunable. +Similar to other parameter component variabilities, some of the tunable parameters may be directly assigned at the events, whereas other tunable parameters will only be updated as a consequence of the direct assignments. +Note that the criterion of being possible to change at an event, as well as the related the semantics of making a change, are tool-dependent. +\end{nonnormative} + \begin{nonnormative} Related to evaluable parameters, the term \firstuse{structural parameter} is also used in the Modelica community. This term has no meaning defined by the specification, and the meaning may vary from one context to another.