- do a bit more simplification

git-svn-id: https://openmodelica.org/svn/OpenModelica/trunk@5008 f25d12d1-65f4-0310-ae8a-bbce733d8d8e
OpenModelica · Feb 19, 2010 · 1e41eb2 · 1e41eb2
1 parent 43e852c
commit 1e41eb2
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Showing 2 changed files with 25 additions and 4 deletions.
diff --git a/Compiler/DAELow.mo b/Compiler/DAELow.mo
@@ -16362,8 +16362,27 @@ end findDelaySubExpressions;
 public function checkEquationBecomesZero
 " function checkEquationBecomesZero
   autor: Frenkel TUD
-  check if a division by zero occurd 
-  because of solving equations"
+  Check if a division by zero occurs 
+  because of solving the equation.
+  The main goal is to support the user with as much 
+  information about equations that cannot be solved
+  because of division by zero. Therefore the expressions of
+  the equation which reside below the slash have to be
+  inspect. The analysis is separated in to
+  - expressions which always be zero ( a-b, with a==b)
+    --> only constants and constant variables
+    --> ErrorMsg during compilation
+  - expressions which constant during simulation but depend 
+    on parameters and bound parameters.
+    --> constants and parameters
+    --> check after parameter adjustment but before 
+        calculation (c_runtime error msg)
+  - expressions which become during simulation equal zero
+    --> constants, parameters, time dependent variables
+    --> WarningMsg during compilation and the possibility  
+        (maybe with flag inside c_runtime) to use the division
+        macro from c_runtime for those equations
+        (therefore we need maybe a new API commant \"compileModel\")"
   input tuple<Equation, list<DAE.Exp>> inEqns;
   input DAELow indlow;
   output DAELow outdlow;
@@ -16378,6 +16397,7 @@ algorithm
       equation
         print(Exp.printExp2Str(exp));
         print("\n");
+        // first seperated the expressions 
         outdlow = checkEquationBecomesZero((eqn,explst),indlow);
     then 
       outdlow;

diff --git a/Compiler/Exp.mo b/Compiler/Exp.mo
@@ -2495,7 +2495,7 @@ algorithm
   matchcontinue (inExp)
     local
       list<Exp> e_lst,e_lst_1,e1_lst,e2_lst,e2_lst_1;
-      Exp res,e,e1,e2;
+      Exp res,res1,e,e1,e2;
       Type tp;
     case ((e as DAE.BINARY(exp1 = e1,operator = DAE.MUL(ty = tp),exp2 = e2)))
       equation 
@@ -2512,8 +2512,9 @@ algorithm
         e_lst = listAppend(e1_lst, e2_lst_1);
         e_lst_1 = simplifyMul(e_lst);
         res = makeProductLst(e_lst_1);
+        res1 = simplify1(res);
       then
-        res;
+        res1;
     case ((e as DAE.BINARY(exp1 = e1,operator = DAE.ADD(ty = tp),exp2 = e2)))
       equation 
         e_lst = terms(e);