Calculations
- Last UpdatedSep 08, 2025
- 7 minute read
Calculations are expressions evaluated during simulation. Calculations can refer to one or many variables within the scheduling model and can be used to display resultant values, or to generate warning and error alerts when the calculation value goes outside a predefined range.
Create calculations
The Calculation Editor is used to edit the definitions of calculations. To open it, click the Add or Edit button in the Home ribbon tab.
The formula for the calculation is entered on the Formula tab, with standard notation and operators, using variables representing values within the supply chain model.
The Formula tab is divided into two panes. The upper pane lists the variables you have defined. The lower pane is where you write the actual formula. When you start typing into this pane, a tooltip appears with a list of matching variable symbols. Click on a symbol to add it to the formula.
To resize the two panes, move the mouse pointer to the gap between them until the
pointer becomes a horizontal line with two arrows (
). Then click and drag to resize.
Add variables. To add a variable to the calculation, click the 
button and choose the Variable Type.
Remove variables. Click the 
icon to remove the selected variables. You can select and delete multiple variables
at a time.
Each variable you add is described by the fields listed in the following table.
|
Item |
Description |
|---|---|
|
Status |
A warning icon
|
|
Variable |
The variable name. See Calculation Variables for more information on the types of variable you can add. |
|
Symbol |
The symbol used to refer to the variable in the calculation formula. |
|
Formula |
If the variable is another calculation, this column displays the formula of the calculation. Blank for all other variable types. |
|
UoM |
The unit of measure in which the value of the variable is expressed. |
appears in this column if there are problems with the variable. Hover your mouse
pointer on the icon to display a tooltip describing the problem.
The Alerts tab is used to define any warning or error ranges for the calculation. If the result of the calculation exceeds the limits an alert is shown in the Tabular pane. You can enter a Min and Max value to define the ranges outside which a Warning and an Error alert are shown.
Calculation variables
Many different types of variables can be added for use in the calculation formula.
Select the Show Material Proportion/Contribution variables check box to include in the list any variables belonging to Material Proportion or Material Contribution types.
|
Item |
Description |
|---|---|
|
Alert Range |
The minimum and maximum values for error and warning ranges of assets. |
|
Asset Group Flow |
The flow of material out of or into an asset group. |
|
Asset Group Inventory |
The cumulative amount of material for the asset group. |
|
Asset Group Material Proportion |
The proportion of a particular material in an asset group. |
|
Asset Group Property |
The property value for a particular asset group. |
|
Calculation |
The result of another calculation. |
|
Flow Material Proportion |
The proportion of a traded material within a pipe flow. |
|
Flow Property |
The value of a property for a pipe flow. |
|
Flow Rate |
The rate of a pipe flow. |
|
Manifold Mode Indicator |
Returns 1 or 0 depending on whether the manifold is in a particular mode at a given point in time, or not. |
|
Material Pool Flow |
The flow of material out of or into a material pool. |
|
Material Pool Inventory |
The cumulative amount of the assets in a material pool. |
|
Material Pool Material Proportion |
The proportion of a given material in a material pool. |
|
Material Pool Property |
The property value for the assets in a material pool. |
|
Operating Parameter |
Operating parameters of type Driver or Prediction defined in the planning case. Also available are minimum and maximum constraints on operating parameters, denoted as Lower Bound and Upper Bound in the Variable column of the Add Variables dialog. |
|
Process Unit Mode Indicator |
Returns 1 or 0 depending on whether the process unit is in a particular mode at a given point in time, or not. |
|
Process Unity Utility Target |
The target on the amount of a certain utility used by a given processing unit. |
|
Stream Material Contribution |
The flow of material originating from a particular material. |
|
Stream Material Property Contribution |
The contribution of a given material to a property value. |
|
Stream Rate Target |
The flow rate target value applied to a particular stream. |
|
Stream Yield |
The proportional yield of process unit outputs relative to other outputs of the process unit. |
|
Tank Inventory |
The amount of material in a tank. |
|
Tank Material Proportion |
The proportion of a traded material in a tank relative to other traded materials in that tank. |
|
Tank Property |
The average property value for a tank. |
|
Utility |
The utility consumption or production of a process unit. |
Tip: Use the grid header to group or filter items based on type. Also use the text box at the top of the dialog box to search for specific variable types.
Variable symbols
Variables are represented by symbols, and these symbols are used in the formulae for the calculation. There are several rules for variable names in order to make them valid for use in these formulae:
-
Symbols are case sensitive. Unit_Capacity and unit_capacity are different symbols representing different variables.
-
Symbols cannot contain spaces. Unit Capacity is not a valid symbol. Either use underscores for spaces, or use CamelCase for names: Unit_Capacity or UnitCapacity.
-
Symbols must start with a letter, not a number, but can have numbers anywhere else within their names. 2Unit_Capacity is not valid, but Unit2_Capacity is valid.
-
Symbols cannot contain special characters or mathematic operators, including *, \, /, +, -, =, <, >, [, ], (, ), @, &, !, ?, ", '.
-
Symbols can only contain characters from the standard ASCII character set. Characters such as à, ç or ß are not supported.
Calculation results
Calculation results are available in several places. In particular, you can add them to charts and to tabular grids, as explained in the following two sections.
Charts
To add calculations to a chart, go to the Display page, then open the Charts pane. Click on the Add, edit and delete views button to open the Charts View Manager.
Click the Create View button, then select the Calculations category on the left.
You can include one or more calculations in the Items list by selecting their check boxes.
Note: If you delete a calculation from the Calculations page, any chart based on that calculation disappears. The chart reappears if you undo the deletion.
Tabular grid
You can add calculation results to the Tabular pane as columns or rows. Three column types are available for each calculation:
-
Average: The average calculation result in the tabular time bucket.
-
End: The calculation value at the end of the time bucket.
-
Start: The calculation value at the start of the time bucket.
Time based parameters
If you wish to model a time based workflow, you can do this using time based parameters.
To add a time based parameter, navigate to the Time Based Parameters page, then click Add in the Manage group of the Home ribbon tab.
This opens the Time Based Parameter Editor, where you can add your data:
Time based parameters can be discrete or continuous. Continuous parameters are linearly interpolated between defined points, as shown in the next image.
As well as in calculations, you can use them in rate targeting, overrides, charts, and on the tabular pane.
The Time Based Parameter Editor can also be opened from the tabular pane, by right-clicking and selecting Time Based Parameters...