Hello,

The following two models are mathematically similar. However when i look at the generated code of the created FMUs, i see that for test1, in which der(x1) and der(x2) appear in the same order in both if and else statements, there is no linear system detected (i.e. test1_03lsy.c is empty) while for test2, it considers the if/else statement as one system of equation. I concluded that, when the order of equations in if/else statements are not in the same order OpenModelica's Symbolic engine is not smart enough to map equations with the if/else statement.

please clarify me with this subject.

Thanks,
Arvin

model test1

  Integer flg;

  Real u, y;

  Real x1, x2;

initial equation

 x1=1;

 x2=1;

equation

u = 1;

flg = if time<1 then 0 else 1;

if flg == 0 then

  der(x1)=-x1+x2^2;

  der(x2)= -2*x2;

else

  der(x1)=-x1+x2^2;

  der(x2)= -2*x2+u;

end if;

  y= x1;

end test1;

model test2

  Integer flg;

  Real u, y;

  Real x1, x2;

initial equation

 x1=1;

 x2=1;

equation

u = 1;

flg = if time<1 then 0 else 1;

if flg == 0 then

  der(x1)=-x1+x2^2;

  der(x2)= -2*x2;

else

  der(x2)= -2*x2+u;

  der(x1)=-x1+x2^2;

end if;

  y= x1;

end test2;