Running a python code with Cplex through FlexSim

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jacopo-r asked May 15, '23 jacopo-r commented May 18, '23

Running a python code with Cplex through FlexSim

Hi all,

I am trying to run Python through FlexSim. I managed to get the connection between python and flexsim (following this https://docs.flexsim.com/en/22.2/Reference/DeveloperAdvancedUser/ConnectingToExternalCode/ConnectingToExternalCode.html#python) and now I want to run a python code that has a cplex optimization algorithm in it. For the moment I am not feeding any tables or parameters, I want to execute the code and return "1" to get a proof that the code went through. It is not working.

I know the code works because I ran it with Jupyter Notebook.
Can anyone help me figuring out what am I missing?

Also, what would be the next step in order to be able to feed a table to the python code and return to flexsim the x[i,j] variable that the cplex calculated?

(Flexsim model and python code attached)cplex_test.fsm Cplex_test_1.py

Thanks

Software Version:

FlexSim 23.0.1

interaction between flexsim and python cplex

cplex-test.fsm (28.4 KiB)

cplex-test-1.py (906 B)

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Attachments: Up to 12 attachments (including images) can be used with a maximum of 23.8 MiB each and 47.7 MiB total.

Answer 1 · 2023-05-15T20:52:43Z

Kavika F answered May 15, '23 jacopo-r commented May 18, '23

Hey @jacopo_r, I found that the issue was that your file name was using underscores in the code but it was named with dashes in the file explorer.

If you edit it to match, then it will work.

Alternate ways to connect:

If you scroll up a little on that same doc page, it will point you to the "External" button which will format the code for Python for you.

If you'd like a more detailed guide, you could check out this post. Ensure that in your Global Preferences you have the correct Python version selected as well.

Hope this helps!

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Attachments: Up to 12 attachments (including images) can be used with a maximum of 23.8 MiB each and 47.7 MiB total.

jacopo-r commented · May 16, 2023 at 06:10 AM

Hi @Kavika F , thanks for your answer.

I did what you suggested but the value I got from the running of the python script is "NULL", while I put a "return 1" at the end of the cplex model just to see if I can actually return something. Does it return "1" to you when you run it?
Can it be that I miss some settings on FlexSim about Cplex?

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Kavika F ♦ jacopo-r commented · May 16, 2023 at 03:14 PM

I got NULL once or twice while testing things out. I think it was because I didn't have the Cplex module installed for my desired version of Python. I had to run

py -3.10 -m pip install cplex

in my windows PowerShell to make sure that it was installed for the correct version of Python because I have 3.10 and 3.11.

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jacopo-r Kavika F ♦ commented · May 16, 2023 at 03:19 PM

So, as far as you know, there is nothing specific to do in order to make sure that FlexSim can properly access Cplex?

Thanks again

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