Model with random problem

Hi,

I'm working on a project and encountering a random issue in my model. For example, if I run the same model twice, I get two different results. This happens even when the Model Stream is locked or while using the Experimenter.

Here are the steps to reproduce the issue:

Restart the computer.
Open the same FlexSim project file twice (the one with the random problem).
Restart the model.
Run the model for 1 month.
Get different results.

Note: The model stream is locked.

To debug this problem, here’s what I’ve done so far:

Checked all globalTables after resetting the model (all were identical).
Checked all labels of 3D objects and Process Flows (all were identical).
Checked all nodes and sub-nodes in the main tree (all were identical).

To ensure the issue is consistently reproducible, I followed these steps:

Restart the computer.
Open the same FlexSim project file twice (the one with the random problem).
Restart the model.
Ran a script to print all nodes and sub-nodes in the main tree for each model instance.
Compared the outputs in WinMerge (both trees were identical).
Ran the model for 1 month.
Got different results again.

Since this project is confidential, I cannot share the file. However, I would like to know if there are other methods or best practices to troubleshoot and resolve this type of random issue.

Software Version:

FlexSim 24.0.6

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Felix Möhlmann commented · Dec 04 at 07:07 AM

Based on your description, the only possible causes left from the repeatability article are declared variables without a default value or what is mentioned under "Non-repeatable data" such as the using the real clock time or memory addresses.

As described there, to debug the model you should take an event log from two runs and compare those to find where they start to diverge.

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Matheus Coelho Felix Möhlmann commented · Dec 04 at 02:33 PM

Thank you, Felix. I'm going to take a look at this material and try to identify the problem using this topic.

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Jeanette F ♦♦ commented · Dec 12 at 12:08 AM

Hi @Matheus Coelho,

We haven't heard back from you. Were you able to solve your problem? If so, please add and accept an answer to let others know the solution. Or please respond to the previous comment so that we can continue to help you.

If we don't hear back in the next 3 business days, we'll assume you were able to solve your problem and we'll close this case in our tracker. You can always comment back at any time to reopen your question, or you can contact your local FlexSim distributor for phone or email help.

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