question

Jyhjeng D2 avatar image
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Jyhjeng D2 asked Jason Lightfoot edited

Set random seed in 3D model

I used a different random seed to see its influence on the statistics in the queue length in a simple queueing model. However, I could not set the seed. Instead, I looked at the Q&A, and they suggested I use toolbox > Modeling Logic > Model Trigger > On Reset.

However, my toolbox did not have such an option.

How could I change the random seed for the source?

Here is my flexsim file.Primer_1-1A.fsm

FlexSim 22.0.1
set random seed in 3d model
primer-1-1a.fsm (28.2 KiB)
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Joerg Vogel avatar image Joerg Vogel commented ·

@Jyhjeng D2, what kind of license do you use? You need a licensed version of FlexSim to get randomized results. A Demo version called express license won’t be able to allow all feature you describe that you are missing. https://answers.flexsim.com/articles/65811/flexsim-features-by-license-type.html

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Jason Lightfoot avatar image Jason Lightfoot ♦♦ Joerg Vogel commented ·

The option would still be there but yield this message when selected:

1676984768473.png

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1676984768473.png (4.3 KiB)
Jyhjeng D2 avatar image Jyhjeng D2 Joerg Vogel commented ·
Got it. I used a trial version. That is why the random seed did not work. Thanks.
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1 Answer

Jason Lightfoot avatar image
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Jason Lightfoot answered Jason Lightfoot edited

Change the random seeds for the streams using the experimenter by either:

  1. Running an experiment and looking at the differing results for each replicaiton
  2. Go to the advanced tab of the experimenter and change the replication to use for your manual run:

1676984837298.png

Make sure you use a non-zero stream number in any stochastic expression (usually best to use getstream(current) or getstream(activity) )

There is another option which is to disable the 'repeat streams' option under the stochastics menu - this has limited use since, should you find anything interesting in terms of results or detecting bugs, you will not be able to replicated it.


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