Do you mean you want to variate parameter a and gather all the results for x at the end of each simulation with the new value of a?

Hi again,

I made a script that does parameter sweep:

loadString("

class Model

  parameter Real a=-1;

  Real x(start=1);

equation

  der(x) = a*x;

end Model;

"); getErrorString();

buildModel(Model); getErrorString();

results := "time,x,\n";

for a in {-2, -1, 1, 2} loop

  str_a := String(a); getErrorString();

  str_cmd := "Model.exe -override a=" + str_a;

  print(str_cmd + "\n"); getErrorString();

  system(str_cmd, "output.txt"); getErrorString();

  res := readSimulationResult("Model_res.mat", x); getErrorString();

  results := results + str_a + "," + String(res[size(res, 1), size(res, 2)]) + ",\n";

  closeSimulationResultFile();

end for;

print(results); getErrorString();

writeFile("results.csv", results);

plot(x, true, "results.csv");

Running the script from command line gets you:

adrpo@ida-liu050 ~/dev/OMTesting/forum/1670

$ /f/OpenModelica1.9.3-v1.9.3-dev-523-g1d963ac/bin/omc +locale=C sweep.mos 

true

""

{"c:/bin/cygwin/home/adrpo/dev/OMTesting/forum/1670/Model","Model_init.xml"}

"Warning: The initial conditions are not fully specified. Use +d=initialization for more information.

"

"time,x,

"

Model.exe -override a=-2

Model.exe -override a=-1

Model.exe -override a=1

Model.exe -override a=2



time,x,

-2,0.135336,

-1,0.367879,

1,2.71829,

2,7.38909,



""

true

true

I used the values of a as the time variable and plotted x at the end of the simulation for each a.

Hi Adrian,

Definitely five start post

I have a question about this line:

results := results + str_a + "," + String(res[size(res, 1), size(res, 2)]) + ",\n";

I know "res" is a matrix, then I guess this line returning the "bottom right" number of the matrix, is that correct?

res[size(res, 1), size(res, 2)]

If so, is this a common way to get value of a variable regardless of time?
Or (ask in another way), in what scenario do we use this code?

Thanks again.

Hi,

Yes, I use:

res[size(res, 1), size(res, 2)]

to get the last value of the variable x as in this case I build a matrix: time, x.

I don't know if is a common way to get the value regardless of time but it works in this case as I know the matrix.
If you don't know how many variables are in the matrix then is better to use val(variable, time).

Cheers,
Adrian Pop/

the command readSimulationResult is VERY useful.
The example from adrpo shows how to use it effectively.
The explanation in: https://build.openmodelica.org/Document … pting.html
is instead cryptic. Maybe a description of the parameters to be passed and an example can be added?
I mean, something like the explanation given in plotParametric().

Hello everyone,

I want to know how we can do a sweep parameter and save results in different csv files.
For example, I have a RC model and I want to change the value of R and save results of the simulation in a csv file.

I tried with a mos script but it didn't work.

Thank you

Nasrou

You could do:

buildModel(Model, outputFormat="csv"); getErrorString();

to output csv files.

Model.exe -override var1=val1 -r File1.csv

Model.exe -override var1=val2 -r File2.csv

It might work, I haven't tried it myself.

https://openmodelica.org/doc/OpenModeli … eter-sweep

Adeel.

hi
  how to write script if i have already build model?and i have to sweep i block parameter and extract that values and plot graph
please help me out.