<< Click to Display Table of Contents >> Navigation:  Initializing Entities > Creating Entity Initialization Data Sets

Step 1: Create and Name an Entity Initialization Data Set

 

•Expand the Entity Initialization Data tab in the Model Overview. Right-click Data Sets and select "New Input Data Set".

 

 

 

•Or, if you have an existing Input Data set you wish to modify, simply right-click the existing set and choose "Make New Copy". A copy will be created, which you can rename by right-clicking.

 

 

Step 2: Add one or more Built-in files

 

Built-in data (Constants, and Initial Values)

Built-in data files store inputs that are not tied to a specific time: constants (whose values are the same at all times) and initial values (whose values apply at whatever time is designated the start time of the simulation).

 

Create a new built-in file by expanding the Entity Initialization Data, right-clicking "Data Sources" and choosing "Add Builtin Data". A new file will appear named "Entities 1" in the entity data folder. "Entities 1" is the name of the builtin file, and you may rename it by right-clicking.

 

The built-in file will open automatically when created, but to open the built-in data file manually, simply double click it or right click it and select "Edit". A window will appear with a tab for each entity type in your model. Each tab has a column for each required value. On each tab:

 

•One entity will be created at the start of the simulation for each enabled row. To enable a row, check the checkbox on the left. (Note that for entity types marked as singular, it will not be possible to enable more than the first row.)

•The "Time" column is where you enter the time when the entity will become active in the simulation. If the value is 0, blank, or prior to simulation start, the entity will be active from the start of the simulation (Example).

•The values you type into each column set the initial values for the entity of that row. If you enter no data, Ventity will take the initial value from the stock or attribute's definition.

•You may enter information for entities, and then un-check the row. That entity will not appear in the simulation, but the information will be stored for future use. To include the entity in a future run, simply enable the entity by checking the box.

•To add more rows, simply click the button. To remove rows, select the rows in question then press the  button. If no rows are selected, the bottom-most row will be removed.

•All of the cells in the built-in data can be cut, copied and pasted into, but will only accept valid entries (pasting 1695.03 into calendar time, which accepts mm/dd/yyyy input, won't work).

•Cells can be deselected by hitting the Esc key, or the data within removed by hitting the Delete key. This won't remove the data, just clear it from the selected cell(s).

 

Once a built-in file has been created, you may use it in multiple Input Data sets: just drag it from one to another in the Model Overview (Example).

 

If you change a variable name in the model, its name in built-in data files will automatically be kept up to date.

 

Step 3: Set the order of the input files.

 

During initialization, Ventity will apply the values from the first (top) file in the set, then the second, then the third, etc. If the same variable is initialized in two or more files, the last value encountered is the one that will be used during the simulation. This makes it possible to organize a suite of runs by placing a set of standard values at the top of the list, and then for each run, change a smaller set of specific overrides in files toward the bottom of the list.

 

If a specific entity (identified by a unique key) appears in an input file that did not appear in previous files, that entity will be created. Default values will be used for any initial values not provided.

 

For additional information on how to effect the order of initialization in specific auxiliaries, see Active Initial.