====== Scenario ======

Scenarios are used for running a sequence of simulations.

Examples of where scenarios are useful:

  * Running simulations where the model is the same but the inputs vary. For instance, a model for the metabolism of substance in the human body can be run for different sets of exposure parameters.
  * Running simulations where the main model is the same, but the values of some [[Expression|expressions]] or [[General_Variable|general variables]] differs. For instance, running a model calculating the doses of a population where the dose expressions depend on different age groups or gender.
  * Testing solver settings. The same model is run several times but with different simulation settings.

===== Defining scenarios =====

Scenarios are defined and listed in the [[Scenarios_window|scenario window]]. This window also allows you to override the simulation settings for specific scenarios.

In order to specify equations or values which are specific to a scenario, you must make the required [[Block|blocks]] scenario dependent by assigning them a [[Index_list|scenario index list]]. The individual values can then be specified by editing the objects directly.

===== Step-by-step =====

To run a sequence of simulations using scenarios, perform the following steps.

  - Create or open a model.
  - In the [[Scenarios_window|scenario window]], create and name each scenario.
  - (Optional) Edit each block which requires values specific to a scenario. Add a dimension to the object and specify the [[Index_list|scenario index list]] for the new dimension. Then write the equations/values specific to the scenario in the same window.
  - (Optional) In the [[Scenarios_window|scenario window]], edit the simulation/probabilistic/sensitivity analysis settings by clicking the corresponding button in the list.
  - In the [[Simulation_Menu|Simulation Menu]], select **Scenarios**
  - Start the simulations by clicking the {{:RunAll24.png|Run}} button on the [[Menu_bar#Toolbar|toolbar]].
  - The [[Results_window|Results window]] will list all the outputs of the simulation, grouped by scenario.

===== Assinging scenario dependent values =====

When a scenario is created in the [[Scenarios_window|scenario window]], an index is automatically added to the [[Index_list|scenario index list]]. To make a block dependent on scenario, you assign this (or an index list which is a sub-set of or mapped to it) index list to a block. Adding this index list to an object does not change the dimension of the block - the block can still be used by objects which are not dependent on scenario. Assign values that are not scenario specific by using the default rows/columns.

===== See also =====

  * Tutorial 8-Scenarios
  * [[Index_list|Index list]]