Arena Simulation Forum

When using the create module with for example the lognormal distribution, and directly dispose all entities, the output is exactly the same when running the model exactly 500 hours for example. However, the output should be variable right?

And I have another question, how are the lognormal mean and lognormal standard deviation for Arena calculated, because when I use my calculated lognormal mean and lognormal standard deviation (which are checked and are correct) the output is much larger than expected. Or does Arena have as input parameter just the normal mean and standard deviation of the data?

Hi Pien,
This is because Arena doesn't change the seed value every time you hit the run button. It only changes the seed value for a new replication. So if you do several replications you will see each one will give a different result as you expected. It is not easy to change the seed value in Arena. You may do it by attaching the "elements" template by right-clicking on any block on the left-hand panel and choosing template panel and then attach... By using the seed element here you can change the seed value. But probably you won't need that and just run multiple replications. You can specify number replications in run setup as you might know already. If you want to get the results even faster you can check the "Batch Run" checkbox under the run ribbon.
If you are looking for further help for developing your Arena simulation model you can download sample case studies or get tutoring consulting help at www.Simulationhelpdesk.com