Is startTime a built-in variable in OMC?

[Francesco Casella]

Consider this test case

model Test
  parameter Real startTime = 1;
end Test;

When simulating it with OMC, the value of startTime is computed to be the value of StartTime in the simulation setup window, completely disregarding the binding equation.

Since startTime is a perfectly legal Modelica parameter name, if you use it in a model some nasty surprises will ensue...

[Adeel Asghar]

Note sure if this is a frontend or backend issue.

[Per Östlund]

Replying to adeas31:

Note sure if this is a frontend or backend issue.

This script returns the correct value:

loadString("
  model Test
    parameter Real startTime = 1;
  end Test;
");

simulate(Test, startTime = 4, stopTime = 5);
readSimulationResult("Test_res.mat", startTime);

So the issue seems to be either with OMEdit or the API commands OMEdit uses to simulate. So I'm kicking it back to OMEdit until someone can show that the issue lies elsewhere.

[Adeel Asghar]

Ah okay I know why its happening. In OMEdit we call the simulation executable like this -override=startTime=4,stopTime=5 (note that this is actually required for re-simulation but to keep the code simple I have used it for both normal and re-simulation). This is overriding the parameter defined in the model. Not sure how fix this. Maybe in the runtime we should have a different override flag for simulation parameters and model parameters.

[Francesco Casella]

See also #3810

[Adrian Pop]

After the discussions in the OSMC dev meeting we decided to go with a new namespace for the settings: -override=settings.startTime=1,startTime=5

[Francesco Casella]

Of course this assumes that nobody will ever put a top-level object named settings containing those parameters in his/her model :)

I guess the likelyhood of that happening is very close to zero...

[Adrian Pop]

We could go for a prefix such as .startTime or $startTime.

[Adeel Asghar]

These are also legal Modelica names.

[Adrian Pop]

@adeas31: names can start with "." but only if they are classes and surely cannot start with "$".

IDENT = NONDIGIT { DIGIT | NONDIGIT } | Q-IDENT
Q-IDENT = "’" ( Q-CHAR | S-ESCAPE ) { Q-CHAR | S-ESCAPE } "’"
NONDIGIT = "_" | letters "a" to "z" | letters "A" to "Z"

[Francesco Casella]

I'm for $startTime. BTW, this also allows to keep backwards compatibility by accepting startTime with the old meaning if the model does not have a top-level startTime parameter, while at the same time issuing a warining such as "please use $startTime instead".

The remaining question is, should we use €startTime instead?

Just kidding :)

[Francesco Casella]

Rescheduled to 1.14.0 after 1.13.0 releasee

[Francesco Casella]

Releasing 1.14.0 which is stable and has many improvements w.r.t. 1.13.2. This issue is rescheduled to 1.16.0

[Francesco Casella]

Retargeted to 1.17.0 after 1.16.0 release

[Francesco Casella]

Retargeted to 1.18.0 because of 1.17.0 timed release.

[Francesco Casella]

Ticket retargeted after milestone closed