Hello,

I am having a problem with variables being set to large parameter values in an initial equation block. I have added a simple model demonstrating this problem.

model SubModel

  parameter Real fillFactor_start = 0.5;

  parameter Real Qtotal;

  

  Real fillFactor;

  Real Qcurrent;

initial equation

  Qcurrent = fillFactor_start * Qtotal;  

equation  

  fillFactor = Qcurrent / Qtotal;

  der(Qcurrent) = 100000;

end SubModel;



model Test

  SubModel m1(Qtotal=60000000000.0);

  SubModel m2(Qtotal=30000000000.0);

end Test;

Depending on the value to be set init the initial equation block I get different results at time=0:

m1.fillFactor = -0.124999999975
m2.fillFactor = 0.5

Looking at the generated code it seems as OpenModelica is calculating the initial residuals for Qcurrent, which I do not think is necessary in this case.

Note also that the values result from wrong calculations for the initial residual using the "nelder_mead_ex" method. Switching to "simplex" method gives the correct results.

I am currently using OpenModelica 1.8.1 (r11436).


Regards,

Michael