Closed #2182

Rewrite merging algorithm, and simplify example and add illegal example.

chapters/synchronous.tex

@@ -1370,52 +1370,46 @@ \subsection{Inferencing of solverMethod}\doublelabel{inferencing-of-solvermethod
 
 If a solverMethod is not explicitly associated with a partition, it is
 inferred with a similar mechanism as for sub-clock inferencing, see
-\autoref{sub-clock-inferencing}. The inferencing mechanism is defined using the operator
-``solverExplicitlyDefined(c)'' which returns \textbf{true}, if a
-solverMethod is explicitly associated with clock c and returns
-\textbf{false} otherwise.
+\autoref{sub-clock-inferencing}. 
 
-For every partitioning operator of \autoref{partitioning-operators}, two clocks c1 and c2
-are defined for the input and the output argument of the operator,
-respectively. Furthermore, for every equality and assignment of clocks,
-c1 = c2 or c1 := c2, two clocks are defined as well. In all these cases,
-the following statements are implicitly introduced:
+For each sub-clock partition we build a set corresponding from this sub-clock partition.
+These sets are then merged as follows: for each set without a specified solverMethod we merge it 
+with sets connected to it (these may contain a solverMethod); and this is repeated until it is not possible to merge more sets.
 
-\begin{lstlisting}[language=modelica]
-if solverExplicitlyDefined(c1) and solverExplicitlyDefined(c2) then
-  // o.k. (no action)
-elseif not solverExplicitlyDefined(c1) and not solverExplicitlyDefined(c2) then
-  assert(c1.solverMethod == c2.solverMethod);
-elseif solverExplicitlyDefined(c1) <>solverExplicitlyDefined(c2) then
-  c1.solverMethod = c2.solverMethod
-end if;
-\end{lstlisting}
-
-The introduced set of, potentially underdetermined or overdetermined
-constraints has to be solved. If no solution exists or if a solution is
-contradictory on some clocks that are associated with clocked
-discrete-time partitions, then this is ignored, since no solverMethod is
-needed for such partitions.
+\begin{itemize}
+\item If this set contains multiple different solverMethods it is an error.
+\item If the set contains continuous time-equations:
+\begin{itemize} 
+\item If this set contains no solverMethod it is an error.
+\item Otherwise we use the specified solverMethod.
+\end{itemize}
+\item If the set does not contain continuous time-equations there is no need for a solverMethod.
+\end{itemize}
 
 {[}\emph{Example:}
 
 \begin{lstlisting}[language=modelica]
-model InferenceTest "Specific clocks set on all partitions. Decouple constraint"
-  ...
+model InferenceTest
+  Real x(start=3) "Explicitly using ExplicitEuler";
+  Real y "Explicitly using ImplicitEuler method";
+  Real z "Inferred to use ExplicitEuler";
 equation 
-  // Physical model
-  der(x1) = -100*x1 + hold(z2);
-  // Controller submodels
-  der(z1) = -100*z1 + sample(x2,
-  Clock(Clock(1, 100), solverMethod="ImplicitEuler"));
-  w = 0.9*previous (w) + superSample(z1, 3);
-  when Clock(Clock(1,20),
-    solverMethod="ExplicitEuler") then 
-    ww = superSample (w);
-  end when
-  der(z2) = -z2 + ww;
+  der(x)=-x+sample(1,Clock(Clock(1,10), solverMethod="ExplicitEuler"));
+  der(y)=subSample(x,2)+sample(1,Clock(Clock(2,10), solverMethod="ImplicitEuler"));
+  der(z)=subSample(x,2)+1;
 end InferenceTest;
+
+model IllegalInference
+  Real x(start=3) "Explicitly using ExplicitEuler";
+  Real y "Explicitly using ImplicitEuler method";
+  Real z;
+equation 
+  der(x)=-x+sample(1,Clock(Clock(1,10), solverMethod="ExplicitEuler"));
+  der(y)=subSample(x,2)+sample(1,Clock(Clock(2,10), solverMethod="ImplicitEuler"));
+  der(z)=subSample(x,4)+1+subSample(y);
+end IllegalInference;
 \end{lstlisting}
+Here z is a continuous-time equation connected directly to both x and y partitions that have different solverMethod.
 {]}
 
 \section{Initialization of Clocked Partitions}\doublelabel{initialization-of-clocked-partitions}