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Vensim Help

Navigation: Reference Guide > Simulating Models

Partial Model Simulation (Not PLE or PLE Plus)

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If you want to simulate just part of a model, use the Model>Partial Simulation command.  To do this:

1.Open the view containing the structure you want to simulate.  Partial Simulation will not work when the Text Editor is open.
2.Highlight those variables in the sketch you want to simulate.  You can do this by dragging over them, or Shift-clicking on them.  It is not possible to include variables from other views.
3.Select Model>Partial Simulation… and continue as you would for a normal simulation.

During Partial Simulation, Vensim will hold all variables that you did not highlight at their initial values.  Any dynamics that occur during the simulation will be the result of feedback between the elements you have highlighted.  This makes partial simulation a very effective way to test hypotheses about the importance of different feedback loops, without having to make any changes to model structure.

Partial simulation still requires a complete model.  If you have one or more incomplete equations you can use partial simulation to simulate an incomplete model as described below.  Simulating an incomplete model might require the definition of placeholders.

If you want to simply cut one feedback loop instead of highlighting feedback loops you can do this by taking a complete model and deleting an arrow involved in the feedback loop.  The variable that the arrow went in to will be marked as unfinished and you can simulate the incomplete model as described in the next section.

Note that it is not possible to perform partial model simulations from the Toolbar.