From b6e3a481295bb99f982da2aede5ba5bb5b86606f Mon Sep 17 00:00:00 2001 From: OLSSON Hans Date: Thu, 2 Sep 2021 14:20:16 +0200 Subject: [PATCH] Actual definition of discrete-time variable. --- chapters/classes.tex | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/chapters/classes.tex b/chapters/classes.tex index eed3fcede..8b33206ca 100644 --- a/chapters/classes.tex +++ b/chapters/classes.tex @@ -344,13 +344,14 @@ \subsection{Component Variability Prefixes discrete, parameter, constant}\label{ \item A variable \lstinline!vc! declared with the \lstinline!parameter!\indexinline{parameter} prefix remains constant during transient analysis, with a value determined by the initialization problem. \item - A \emph{discrete-time} variable \lstinline!vd! has a vanishing time derivative between events. + A \emph{discrete-time} variable \lstinline!vd! is a variable declared with the \lstinline!discrete!\indexinline{discrete} prefix, or a variable without any prefix that is not a continuous-time variable. + It has a vanishing time derivative between events. Note that this is not the same as saying that \lstinline!der(vd)=0! almost everywhere, as the derivative is not even defined at the events, and it is not legal - to apply \lstinline!der! to discrete-time variables as they are not continuous. During transient analysis the variable - can only change its value at event - instants (see \cref{events-and-synchronization}). + to apply \lstinline!der! to discrete-time variables as they are not continuous. + During transient analysis the variable can only change its value at event instants (see \cref{events-and-synchronization}). \item + A continuous-time variable is a \lstinline!Real! variable without any prefix that is not assigned in a \lstinline!when!-clause. A \emph{continuous-time} variable \lstinline!vn! may have a non-vanishing time derivative (\lstinline!der(vn)<>0! possible) and may also change its value discontinuously at any time during transient analysis