Incorrect message about cyclic parameters

[Michael Wetter]

Simulating TestPackage.Example gives the error

Cyclically dependent constants or parameters found in scope `TestPackage.TestModel`

Here is a test model that illustrates the construct we use:

package TestPackage
model Example
  TestModel t(set_a = true, a = 2);
end Example;

model TestModel
  parameter Boolean set_a = true "Set to true to set parameter a";
  parameter Real a = b
    annotation(Dialog(enable=set_a));
  parameter Real b = a
    annotation(Dialog(enable=not set_a));
end TestModel;
end TestPackage;

I agree that TestPackage.TestModel has a cyclic dependency, but when used in TestPackage.Example, this dependency is removed by setting a=2, hence there is no need to issue the error.

A use case for such a construct is Annex60.Fluid.Chillers.Examples.Carnot_TEva in which the user can specify a Carnot effectiveness from which the Carnot efficiency is computed, or vice versa, depending on a parameter such as set_a.

This is used in 15 out of the 20 regression tests of Annex 60 that fail. Can this test be delayed in OpenModelica until the parameters are assigned?

[Lennart Ochel]

I set the component to frontend, since that is where the error is thrown. I am pretty sure that I've implemented a similar check in the backend. So maybe the frontend check is not needed.

[Matthis Thorade <m.thorade@…>]

See example of error message here:

• ​https://libraries.openmodelica.org/branches/master/IBPSA_latest/files/IBPSA_latest_IBPSA.Fluid.Chillers.Examples.Carnot_y.err
• ​https://libraries.openmodelica.org/branches/master/IBPSA_latest/files/IBPSA_latest_IBPSA.Fluid.HeatPumps.Examples.Carnot_y.err

And here is the IBPSA github issue:
​https://github.com/ibpsa/modelica-ibpsa/issues/455

[Matthis Thorade <m.thorade@…>]

Another note: When simulating with OMC Flag -d=ignoreCycles as suggested by the error message the models run just fine. So this issue is really only about when to apply the check.