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Python Script inside model

#9621  Permalink Top

Python Script inside model

Jan-13-20 09:39:18

Dear modellica users,

I am quiet new in Modelica and trying to create a model to be exported into an FMU. Right now I am looking for tutorials to understand how modelica works and cannot achieve to execute a very simple python script inside a model. I have found this “Interoperability – C and Python”:
https://openmodelica.ida.liu.se/doc/OpenModelicaUsersGuide/latest/interop_c_python.html
But it does not give the structure of the python script.

I have created a pyRunString.py script with the following:

Code:

def pyRunString(s): 

    print(s)

And I have compilation errors:
When keeping the line

Code:

Py_SetProgramName(\"pyRunString\"); /* optional but recommended */

I get:

Code:

In file included from CallExternalPython_functions.c:7:0:

CallExternalPython_includes.h: In function 'pyRunString':

CallExternalPython_includes.h:9:21: warning: passing argument 1 of 'Py_SetProgramName' from incompatible pointer type [-Wincompatible-pointer-types]

Py_SetProgramName("pyRunString"); /* optional but recommended */

^

In file included from C:/Users/cabecerrilaguirre/AppData/Local/Continuum/anaconda3/include/Python.h:140:0,

from CallExternalPython_includes.h:5,

from CallExternalPython_functions.c:7:

C:/Users/cabecerrilaguirre/AppData/Local/Continuum/anaconda3/include/pylifecycle.h:40:18: note: expected 'const wchar_t * {aka const short unsigned int *}' but argument is of type 'char *'

PyAPI_FUNC(void) Py_SetProgramName(const wchar_t *);

When I delete it:

Code:

CallExternalPython_functions.o:CallExternalPython_functions.c:(.text+0xb): undefined reference to `__imp_Py_Initialize'

CallExternalPython_functions.o:CallExternalPython_functions.c:(.text+0x18): undefined reference to `__imp_PyRun_SimpleStringFlags'

CallExternalPython_functions.o:CallExternalPython_functions.c:(.text+0x24): undefined reference to `__imp_Py_Finalize'

collect2.exe: error: ld returned 1 exit status

CallExternalPython.makefile:32: recipe for target 'omc_main_target' failed

mingw32-make: *** [omc_main_target] Error 1

mingw32-make: Leaving directory 'C:/Users/CABECE~1/AppData/Local/Temp/OPENMO~1'

RESULT: 2

Could you please somebody help me to understand?

#9633  Permalink Top

Re: Python Script inside model

Jan-14-20 16:15:56

Anyone? Please?

#9664  Permalink Top

Re: Python Script inside model

Jan-18-20 13:12:54

I made a small package to call python from OM. See here:
https://github.com/adrpo/OMCallPython/

#9669  Permalink Top

Re: Python Script inside model

Jan-20-20 14:11:01

Dear adrpo,

Thank you very much for the package. I am using python 3.7 with anaconda. I have changed the Py.run print command with the parenthesis and the python37.dll in both "om" files. However, even if the compilation is finished without errors, I have an error with the encoding:

Fatal Python error: initfsenconding: unable to laod the file system codec

ModuleNotFoundError: No module named 'encodings'

Current thread 0x00002314 (most recent call first):
Simulation process failed. Exited with code 3

By the way, the OMCallPython.h file is something that you have written or it can be generated easily for a more complex python code?

Thank you very much!

#9671  Permalink Top

Re: Python Script inside model

Jan-21-20 10:20:58

See here: https://stackoverflow.com/questions/569 … stem-codec
maybe this is your issue.

I wrote OMCallPython.h myself, you can change it as you want to add more functionality if you need to communicate data between python and Modelica,
see 1.3 from: https://docs.python.org/3/extending/embedding.html


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