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Connecting a huge number of ports

#9498  Permalink Top

Connecting a huge number of ports

Nov-27-19 16:48:10

Hi there!

I am a moderate experienced Modelica (Dymola) User. So i hope you guys could help me. current/smile

I want to build up a model with a huge number of ports (>60). They are named like "portxn_1_1, portxn_2_1, portxn_3_1, portxn_1_2, portxn_1_2, ..." and so on.
The first thing is that i don't want to connect them in the diagram editor or by manually programing to connect them with other variables, like this "portxn_1_1.T = Txn[1,1] ; portxn_2_1.T = Txn[2,1] ; portxn_3_1.T = Txn[3,1] ; ..." . So i tried to connect them by a loop, which loops through the numbers "1_1" of the "portxn".
For example like this:

for i in 1:ni loop
  portxn_"i"_1.T = Txn[i,1];
end for;

That's the first problem. At my point of view there is no opportunity to loop through a String in Modelica. My first idea was to program the loop in C and include it with as a external function.

Is this the right way? Does anybody have some ideas? Maybe a example or something?  current/smile
Thanks!

#9502  Permalink Top

Re: Connecting a huge number of ports

Nov-27-19 22:30:25

I guess what you want is meta-programming. Write some scripting that builds the model for you.
As far as I know Dymola has a library for this called ModelManangement but I'm not really sure it it can be used to add new connections to classes.

I think the easiest would be to just generate the model file from some other language like python.

You can also do this in OpenModelica with a bit of scripting: buildModel.mos

Code:


// you can also load this via loadFile("File.mo"); if you already have the skeleton

loadString("

model TestConn 

  connector C

    Real T;

  end C;

  model M

    C c_1;

    C c_2;

    C c_3;

    C c_4;

  end M;

  M m;

  Real Txn[4,1];

  equation 

end TestConn;

"); // load the model skeleton



n := 4;

// build the connect commands as strings

connectStrings := "";

for i in 1:n loop

  connectStrings := connectStrings + "addConnection(m.c_"+String(i)+".T, Txn["+ String(i) + ",1], TestConn); getErrorString();\n";

end for;



// write the connect commands to a new .mos script

writeFile("addConnects.mos", connectStrings); getErrorString();

// run the script with the connect commands to be added to the model

runScript("addConnects.mos"); getErrorString();



str := list(TestConn); getErrorString();

"write the model file";

writeFile("TestConn.mo", str);

"--- read the model file ---";

readFile("TestConn.mo");

output of running this via omc:

Code:


adrpo33@ida-0030 MINGW64 /c/home/adrpo33/dev/OMTesting/

$ ~/dev/OpenModelica/build/bin/omc buildModel.mos

true

4

""



true

""

"Ok

\"\"

Ok

\"\"

Ok

\"\"

Ok

\"\"

"

""

"model TestConn

  connector C

    Real T;

  end C;



  model M

    C c_1;

    C c_2;

    C c_3;

    C c_4;

  end M;



  M m;

  Real Txn[4, 1];

equation

  connect(m.c_1.T, Txn[1, 1]);

  connect(m.c_2.T, Txn[2, 1]);

  connect(m.c_3.T, Txn[3, 1]);

  connect(m.c_4.T, Txn[4, 1]);

end TestConn;"

""

"write the model file"

true

"--- read the model file ---"

"model TestConn

  connector C

    Real T;

  end C;



  model M

    C c_1;

    C c_2;

    C c_3;

    C c_4;

  end M;



  M m;

  Real Txn[4, 1];

equation

  connect(m.c_1.T, Txn[1, 1]);

  connect(m.c_2.T, Txn[2, 1]);

  connect(m.c_3.T, Txn[3, 1]);

  connect(m.c_4.T, Txn[4, 1]);

end TestConn;"

Edited by: adrpo - Nov-27-19 22:35:44
#9506  Permalink Top

Re: Connecting a huge number of ports

Nov-28-19 10:04:13

Thanks for your answer!

Ok, this seems to be a good method to solve this problem. But the next problem is, that i don't have all these functions ( loadString, loadFile, writeFile, readFile) in Dymola. Do i have to activate them in the options or something?

#9507  Permalink Top

Re: Connecting a huge number of ports

Nov-28-19 13:01:34

Yes, these are mostly all OpenModelica specific, i think loadFile is available in Dymola as well.
What I show you was a prof of concept done using OpenModelica scripting, you need to find from Dymola's manual and documentation if this is possible to do and how.

#9508  Permalink Top

Re: Connecting a huge number of ports

Nov-28-19 15:32:19

You could also use a Python script or whatever to generate this file. Then open it in Dymola.

#9517  Permalink Top

Re: Connecting a huge number of ports

Nov-29-19 10:32:43

Ok, i think i solved this problem with your help current/smile
I've done it without saving. Just copy and paste the command output.

Next question. How do i assign one start value for each cell in a 3D Matrix with variable size? Like this

Code:


...

Integer ni=3;

Integer nj=3;

Integer nk=3;



Real Tc_start=50;



Real Tc[ni,nj,nk](start=Tc_start);

...

Thanks again!

#9529  Permalink Top

Re: Connecting a huge number of ports

Dec-05-19 14:10:31

Does somebody know the answer?

current/big_smile

#9530  Permalink Top

Re: Connecting a huge number of ports

Dec-05-19 15:47:23

For that you don't need any weird stuff, you do:

Code:


parameter Integer ni=3;

parameter Integer nj=3;

parameter Integer nk=3;

parameter Real Tc_start=50;

Real Tc[ni,nj,nk](each start=Tc_start);

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