Determine the number of a specific component in a Modelica model at translation (using Dymola)

If you can modify the model ModelToBeCounted you can do this using inner/outer:

  connector C
    Real totalNum;
    flow Real addNum;
  end C;

  model InnerObjectCounter
    C c;
  equation 
    c.totalNum+c.addNum=0 "Correct sign";
    annotation(missingInnerMessage="Add inner component to count objects");
  end InnerObjectCounter;

  model FlowSource
    C c;
  equation 
    c.addNum=1;
  end FlowSource;


  model AddCounter
    outer InnerObjectCounter objectCounter;
    final Integer totalNum=integer(flowSource.c.totalNum);
    FlowSource flowSource;
  equation 
    connect(flowSource.c, objectCounter.c);
  end AddCounter;

  model ModelToBeCounted
    AddCounter c;
  end ModelToBeCounted;

All components are automatically connected to the inner object using inner/outer-mechanism, and they have a flow of 1 that is summed together.

If you cannot modify the model ModelToBeCounted, and you are willing to use non-standarized methods you can set the flag:

Hidden.AllowAutomaticInstanceOf=true;

and then use:

final parameter Integer m=sum(1 for m in P.ModelToBeCounted);

From: https://github.com/modelica/ModelicaSpecification/blob/MCP/0021/RationaleMCP/0021/

The ModelManagement library can do that.

In fact, there is exactly what you need available as a function:

ModelManagement.Structure.Instantiated.CountUsedModels("Example", {"ModelToBeCounted"});
= {3}

The library is installed with Dymola and available with the standard license. You just have to open it from the Libraries menu.

A problem could be, that this function has to translate your model. I am not sure how well this will work for your requirement:

This size is to be used to set the size of a vector.