Use start values at first clock tick (ticket:3770)

This shall only apply to states of solved continuous equations.
We check for the existence of a solver method so far.

Compiler/BackEnd/BackendDAE.mo

@@ -246,6 +246,7 @@ uniontype VarKind "variable kind"
   record DUMMY_STATE end DUMMY_STATE;
   record CLOCKED_STATE
     .DAE.ComponentRef previousName "the name of the previous variable";
+    Boolean isStartFixed "is fixed at first clock tick";
   end CLOCKED_STATE;
   record DISCRETE end DISCRETE;
   record PARAM end PARAM;

Compiler/BackEnd/SynchronousFeatures.mo

@@ -290,7 +290,9 @@ algorithm
     for i in 1:arrayLength(isPrevVarArr) loop
       if isPrevVarArr[i] then
         var := BackendVariable.setVarFixed(BackendVariable.getVarAt(inSyst.orderedVars, i), true);
-        var := BackendVariable.setVarKind(var, BackendDAE.CLOCKED_STATE(previousName = ComponentReference.crefPrefixPrevious(var.varName)));
+        var := BackendVariable.setVarKind(var, BackendDAE.CLOCKED_STATE(
+                 previousName = ComponentReference.crefPrefixPrevious(var.varName),
+                 isStartFixed = isSome(subPartition.clock.solver)));
         BackendVariable.setVarAt(inSyst.orderedVars, i, var);
         prevVars := var.varName::prevVars;
       end if;

Compiler/Template/CodegenCpp.tpl

@@ -9815,6 +9815,7 @@ case SIMCODE(modelInfo = MODELINFO(__), modelStructure = fmims) then
           _clockInterval[<%i%>] = <%interval%> * <%fnom%>.0 / <%fres%>.0;
           _clockShift[<%i%>] = <%snom%>.0 / <%sres%>.0;
           _clockTime[<%i%>] = _simTime + _clockShift[<%i%>] * _clockInterval[<%i%>];
+          _clockStart[<%i%>] = true;
           <%i%> ++;
           >>
       ; separator="\n")
@@ -11564,6 +11565,9 @@ template equationSimpleAssign(SimEqSystem eq, Context context,Text &varDecls, Si
 match eq
 case SES_SIMPLE_ASSIGN(__) then
   let &preExp = buffer "" /*BUFD*/
+  let startFixedExp = match cref2simvar(cref, simCode)
+    case SIMVAR(varKind = CLOCKED_STATE(isStartFixed = true)) then
+      "if (_clockStart[clockIndex - 1]) return;"
   let expPart = daeExp(exp, context, &preExp, &varDecls, simCode, &extraFuncs, &extraFuncsDecl, extraFuncsNamespace, stateDerVectorName, useFlatArrayNotation)
 
   match cref
@@ -11585,6 +11589,7 @@ case SES_SIMPLE_ASSIGN(__) then
   let &assignExp += cref1(cref, simCode , &extraFuncs , &extraFuncsDecl,  extraFuncsNamespace, context, varDecls, stateDerVectorName, useFlatArrayNotation)
   let &assignExp += if(assignToStartValues) then ',<%expPart%>,<%overwriteOldStartValue%>);' else ' = <%expPart%>;'
   <<
+  <%if not assignToStartValues then '<%startFixedExp%>'%>
   <%preExp%>
   <%assignExp%>
   >>
@@ -12759,6 +12764,9 @@ template clockedPartFunctions(Integer i, list<tuple<SimCodeVar.SimVar, Boolean>>
 
   void <%className%>::<%funcName%>(const UPDATETYPE command)
   {
+    if (_simTime > _clockTime[<%idx%>]) {
+      _clockStart[<%idx%>] = false;
+    }
     <%funcCalls%>
     if (_simTime > _clockTime[<%idx%>]) {
       _clockInterval[<%idx%>] = _simTime - _clockTime[<%idx%>];

Compiler/Template/SimCodeTV.mo

@@ -1071,6 +1071,7 @@ package BackendDAE
     record DUMMY_STATE end DUMMY_STATE;
     record CLOCKED_STATE
       DAE.ComponentRef previousName "the name of the previous variable";
+      Boolean isStartFixed "is fixed at first clock tick";
     end CLOCKED_STATE;
     record DISCRETE end DISCRETE;
     record PARAM end PARAM;

SimulationRuntime/cpp/Core/System/SystemDefaultImplementation.cpp

@@ -55,7 +55,8 @@ SystemDefaultImplementation::SystemDefaultImplementation(IGlobalSettings *global
   , _clockInterval  (NULL)
   , _clockShift     (NULL)
   , _clockTime      (NULL)
-   , _clockCondition(NULL)
+  , _clockCondition (NULL)
+  , _clockStart     (NULL)
   , _outputStream(NULL)
   , _callType        (IContinuous::UNDEF_UPDATE)
   , _initial        (false)
@@ -91,7 +92,8 @@ SystemDefaultImplementation::SystemDefaultImplementation(SystemDefaultImplementa
   , _clockInterval  (NULL)
   , _clockShift     (NULL)
   , _clockTime      (NULL)
-  , _clockCondition(NULL)
+  , _clockCondition (NULL)
+  , _clockStart     (NULL)
   , _outputStream(NULL)
   , _callType        (IContinuous::UNDEF_UPDATE)
   , _initial        (false)
@@ -134,7 +136,8 @@ SystemDefaultImplementation::~SystemDefaultImplementation()
   if(_clockInterval) delete [] _clockInterval;
   if(_clockShift) delete [] _clockShift;
   if(_clockTime) delete [] _clockTime;
-   if(_clockCondition) delete [] _clockCondition;
+  if(_clockCondition) delete [] _clockCondition;
+  if(_clockStart) delete [] _clockStart;
 }
 
 void SystemDefaultImplementation::Assert(bool cond,const string& msg)
@@ -237,18 +240,17 @@ void SystemDefaultImplementation::initialize()
     _clockShift = new double [_dimClock];
     if (_clockTime) delete [] _clockTime;
     _clockTime = new double [_dimClock];
-	  if (_clockCondition) delete [] _clockCondition;
+    if (_clockCondition) delete [] _clockCondition;
     _clockCondition = new bool [_dimClock];
-	memset(_clockCondition,false,(_dimClock)*sizeof(bool));
+    memset(_clockCondition,false,(_dimClock)*sizeof(bool));
+    if (_clockStart) delete [] _clockStart;
+    _clockStart = new bool [_dimClock];
   }
   _start_time = 0.0;
   _terminal = false;
   _terminate = false;
-  _clockStart = true;
-
 };
 
-
 /// Set current integration time
 void SystemDefaultImplementation::setTime(const double& t)
 {

SimulationRuntime/cpp/Include/Core/System/SystemDefaultImplementation.h

@@ -181,8 +181,8 @@ class BOOST_EXTENSION_SYSTEM_DECL SystemDefaultImplementation
     double *_clockInterval;   ///< time interval between clock ticks
     double *_clockShift;      ///< time before first activation
     double *_clockTime;       ///< time of clock ticks
-	bool* _clockCondition;    ///< clock tick active
-	bool _clockStart;         ///< only active at clock start
+    bool *_clockCondition;    ///< clock tick active
+    bool *_clockStart;        ///< only active at clock start
     std::ostream *_outputStream;        ///< Output stream for results
 
     IContinuous::UPDATETYPE _callType;