Treat array flows as array equations and solve them for code generation

Note that ExpressionSolve.solveSimpleEquations does not cover array
equations, even though it would work. This is why SimCodeUtil calls
ExpressionSolve.solve2 now.

Belonging to [master]:
  - #2776
  - OpenModelica/OpenModelica-testsuite#1072

Author: rfranke

Compiler/NFFrontEnd/NFConnectEquations.mo

@@ -304,7 +304,7 @@ algorithm
     end for;
   end if;
 
-  equations := {Equation.EQUALITY(sum, Expression.REAL(0.0), Type.REAL(), src)};
+  equations := {Equation.EQUALITY(sum, Expression.REAL(0.0), c.ty, src)};
 end generateFlowEquations;
 
 function makeFlowExp

Compiler/SimCode/SimCodeUtil.mo

@@ -1591,7 +1591,7 @@ algorithm
         (eqnlst, varlst,_) = BackendDAETransform.getEquationAndSolvedVar(comp, syst.orderedEqs, syst.orderedVars);
         // States are solved for der(x) not x.
         varlst = List.map(varlst, BackendVariable.transformXToXd);
-        (equations1,_, uniqueEqIndex1, tempvars) = createSingleArrayEqnCode(true, eqnlst, varlst, uniqueEqIndex, tempvars, shared.info);
+        (equations1,_, uniqueEqIndex1, tempvars) = createSingleArrayEqnCode(true, eqnlst, varlst, uniqueEqIndex, tempvars, shared);
 
         eqSccMapping = appendSccIdxRange(uniqueEqIndex, uniqueEqIndex1 - 1, sccIndex, eqSccMapping);
         eqBackendSimCodeMapping = appendSccIdxRange(uniqueEqIndex, uniqueEqIndex1 - 1, e, eqBackendSimCodeMapping);
@@ -1828,12 +1828,12 @@ algorithm
       then (equations1, equations1, uniqueEqIndex, tempvars);
 
       // A single array equation
-    case (_, _, _, BackendDAE.EQSYSTEM(orderedVars=vars, orderedEqs=eqns), BackendDAE.SHARED(info = ei), BackendDAE.SINGLEARRAY())
+    case (_, _, _, BackendDAE.EQSYSTEM(orderedVars=vars, orderedEqs=eqns), _, BackendDAE.SINGLEARRAY())
       equation
         (eqnlst, varlst,_) = BackendDAETransform.getEquationAndSolvedVar(comp, eqns, vars);
         // States are solved for der(x) not x.
         varlst = List.map(varlst, BackendVariable.transformXToXd);
-        (equations1, noDiscEquations1, uniqueEqIndex, tempvars) = createSingleArrayEqnCode(genDiscrete, eqnlst, varlst, iuniqueEqIndex, itempvars, ei);
+        (equations1, noDiscEquations1, uniqueEqIndex, tempvars) = createSingleArrayEqnCode(genDiscrete, eqnlst, varlst, iuniqueEqIndex, itempvars, shared);
       then (equations1, noDiscEquations1, uniqueEqIndex, tempvars);
 
         // A single algorithm section for several variables.
@@ -5477,7 +5477,7 @@ protected function createSingleArrayEqnCode
   input list<BackendDAE.Var> inVars;
   input Integer iuniqueEqIndex;
   input list<SimCodeVar.SimVar> itempvars;
-  input BackendDAE.ExtraInfo iextra;
+  input BackendDAE.Shared shared;
   output list<SimCode.SimEqSystem> equations_;
   output list<SimCode.SimEqSystem> noDiscequations;
   output Integer ouniqueEqIndex;
@@ -5493,7 +5493,7 @@ algorithm
       inEquation.right := Expression.replaceDerOpInExp(inEquation.right);
     then inEquation;
     end match;
-  (equations_, noDiscequations, ouniqueEqIndex, otempvars) := matchcontinue(genDiscrete, inEquation, inVars, iuniqueEqIndex, itempvars, iextra)
+  (equations_, noDiscequations, ouniqueEqIndex, otempvars) := matchcontinue(genDiscrete, inEquation, inVars)
     local
       list<Integer> ds;
       DAE.Exp e1, e2, lhse, rhse;
@@ -5502,35 +5502,24 @@ algorithm
       list<BackendDAE.Var> vars;
       DAE.ComponentRef cr, cr_1, left;
       BackendDAE.Variables evars, vars1;
-      BackendDAE.EquationArray eeqns, eqns_1;
-      FCore.Cache cache;
-      FCore.Graph graph;
       DAE.FunctionTree funcs;
       DAE.ElementSource source;
-      BackendDAE.Variables av;
-      BackendDAE.BackendDAE subsystem_dae;
       SimCode.SimEqSystem equation_;
       list<SimCode.SimEqSystem> eqSystlst;
-      BackendDAE.StrongComponents comps;
-      BackendDAE.EqSystem syst;
-      BackendDAE.Shared shared;
       Integer uniqueEqIndex;
       String str;
       list<DAE.Dimension> dims;
       list<SimCodeVar.SimVar> tempvars;
       BackendDAE.EquationAttributes eqAttr;
-      BackendDAE.Equation eq1;
-      HashSet.HashSet ht;
-      list<DAE.ComponentRef> crefs, crefstmp;
+      list<DAE.ComponentRef> crefstmp;
       DAE.Type ty,basety;
       list<tuple<DAE.Exp, DAE.Exp>> exptl;
 
-
     // An array equation
     // {z1,z2,..} = rhsexp -> solved for {z1,z2,..}
     // => tmp = rhsexp;
     // z1 = tmp[1]; z2 = tmp[2] ....
-    case (_, (BackendDAE.ARRAY_EQUATION(dimSize=ds, left=e1, right=e2, source=source, attr=eqAttr)), _, _, _, _)
+    case (_, (BackendDAE.ARRAY_EQUATION(dimSize=ds, left=e1, right=e2, source=source, attr=eqAttr)), _)
     guard Expression.isMatrix(e1) or Expression.isArray(e1)
     equation
       // Flattne multi-dimensional ARRAY{ARRAY} expressions
@@ -5556,7 +5545,7 @@ algorithm
 
     // An array equation
     // cref = rhsexp
-    case (_, (BackendDAE.ARRAY_EQUATION(left=e1 as DAE.CREF(cr_1, _), right=e2, source=source, attr=eqAttr)), BackendDAE.VAR(varName=cr)::_, _, _, _)
+    case (_, (BackendDAE.ARRAY_EQUATION(left=e1 as DAE.CREF(cr_1, _), right=e2, source=source, attr=eqAttr)), BackendDAE.VAR(varName=cr)::_)
     guard ComponentReference.crefEqual(cr_1, ComponentReference.crefStripLastSubs(cr))
     equation
       (e1, _) = BackendDAEUtil.collateArrExp(e1, NONE());
@@ -5567,7 +5556,7 @@ algorithm
 
     // An array equation
     // lhsexp = cref
-    case (_, (BackendDAE.ARRAY_EQUATION(left=e1, right=e2 as DAE.CREF(cr_1, _), source=source, attr=eqAttr)), BackendDAE.VAR(varName=cr)::_, _, _, _)
+    case (_, (BackendDAE.ARRAY_EQUATION(left=e1, right=e2 as DAE.CREF(cr_1, _), source=source, attr=eqAttr)), BackendDAE.VAR(varName=cr)::_)
     guard ComponentReference.crefEqual(cr_1, ComponentReference.crefStripLastSubs(cr))
     equation
       (e1, _) = BackendDAEUtil.collateArrExp(e1, NONE());
@@ -5576,10 +5565,24 @@ algorithm
       uniqueEqIndex = iuniqueEqIndex + 1;
     then ({equation_}, {equation_}, uniqueEqIndex, itempvars);
 
+    // An array equation
+    // lhsexp = rhsexp
+    case (_, (BackendDAE.ARRAY_EQUATION(left=lhse, right=rhse, source=source, attr=eqAttr)), BackendDAE.VAR(varName=cr)::_)
+    equation
+      (lhse, _) = BackendDAEUtil.collateArrExp(lhse, NONE());
+      (rhse, _) = BackendDAEUtil.collateArrExp(rhse, NONE());
+      BackendDAE.SHARED(functionTree = funcs) = shared;
+      e1 = Expression.crefExp(cr);
+      e2 = ExpressionSolve.solve2(lhse, rhse, e1, SOME(funcs), SOME(iuniqueEqIndex), true, BackendDAEUtil.isSimulationDAE(shared));
+      equation_ = SimCode.SES_ARRAY_CALL_ASSIGN(iuniqueEqIndex, e1, e2, source, eqAttr);
+      uniqueEqIndex = iuniqueEqIndex + 1;
+    then ({equation_}, {equation_}, uniqueEqIndex, itempvars);
+
     // failure
     else equation
+      BackendDAE.VAR(varName = cr)::_ = inVars;
       str = BackendDump.dumpEqnsStr(inEquations);
-      str = "for Eqn: " + str + "\narray equations currently only supported on form v = functioncall(...)";
+      str = "solving array equation: " + str + "\nfor variable: " + ComponentReference.crefStr(cr) + ".";
       Error.addInternalError(str, sourceInfo());
     then fail();
   end matchcontinue;