Connecting Custom Functions

Custom functions and methods can be used to enhance expression capabilities due to the use of custom calculation methods. Custom functions are available for use in:

Custom functions are not connected to the tools by default, and they should be entered manually in the expression each time to be used. Foresight Analytics Platform enables the user to connect custom functions to system functions in all tools defined above.

NOTE. Connecting custom functions is available for the users included in the Administrators group.

For example, in the expression editor they are displayed on the functions panel in the Custom Functions category:

To connect custom functions, use the Methods tab in the Custom Metadata section of the Parameters dialog box. All methods added on this tab will be connected to the custom functions section in the Foresight Analytics Platform tools.

The tab contains custom functions divided by folders. Folders are categories that are used to arrange and group functions. Custom functions grouped by categories are displayed in the Time Series Analysis and Modeling and Forecasting tools. In the expression editor and the Calculation Algorithms and Reports tools, custom functions are displayed without division on categories.

NOTE. A custom function should have a unique name. If after a unit or assembly is selected that contains a function, which name matches with any function or system method or function added before, an exception is thrown. The use of such a unit or assembly will be unavailable.

To add a category, select the item:

Category in the Add button drop-down menu.
Add a category in the context menu of the list of methods.

The category will be added to the Methods tab. The category name will be in edit mode. Enter category name and press ENTER.

Notice, that the category cannot be added to another category.

To add and set up a method:

Select category to which the method will be added. If none of the categories is not selected, the method will be added without category.
Add a method. To do this:

Click the Add button.
Select the Method item in the drop-down menu of the Add button.
Select the Add method item in the context menu of the list of methods.

The method will be added to the selected category on the Methods tab. The method name will be in the edit mode. Enter the method name and press the ENTER key.
Select a Fore form, nit or assembly in the Assembly, Unit or Form drop-down list.
In the Method drop-down list select the procedure or function implementing the method. The list will contain all available procedures and functions from the object selected in the Assembly, Unit or Form list.
Specify method type in the Type list:

Arithmetical. It is used by default. It is used to calculate single value.
Pointwise. The calculation is individual for each point of data series.
Series. the calculation is performed for the whole data series.

Notice, that the method type is used to its classification and not to determine method calculation mode. The calculation mode is pre-defined and depends on the tool in use.

NOTE. The Modeling and Forecasting tool provides only series methods.

Use the Description field to specify brief description for a method that will be displayed to user. The description is displayed in expression editor, function wizard in the Reports and formula editor in the Calculation Algorithms tools.
If method is parametric, it is available to set up method parameters. To do this, click the Options button. If the button is not available, the method is not parametric.

The Parameters dialog box opens:

The window contains the list of all method parameters. To est up parameter:

Select a parameter in the list. The Data Type filed will display the data type of the parameter specified in the method. It is not possible to change parameter data type.
Determine value of default parameter in the Value field. Data type of the specified value must match the parameter data type.
If on creating method, the default value was set for the parameter, it will be displayed in the Value field. This value can be modified.
Use the Description box to specify brief description for the parameter, which is displayed to the user. The description is displayed in expression editor, function wizard in the Reports and formula editor in the Calculation Algorithms tool.

As a result, method will be added and set up.

NOTE. To connect custom function with Fore language, use the IForeMethods.Add method.

To edit method, select it in the list. Method settings will be displayed in corresponding fields. Change required values.

To rename selected method or category:

Press F2.
Select the Rename context menu item.
Click the method or category.

The named will be displayed in the edit mode. Enter a new name of method or category and press the ENTER key.

To set up order of selected method or category:

Use the Up and Down buttons.
Move up or down a category in the list. Use this method to change method category.

Notice, that category cannot be placed inside another category.

To remove selected method or category:

Click the Remove button.
Select the Remove context menu item.
Press CTRL+DELETE.

A request to confirm the executed operation appears. On confirming it, method or category will be removed. If the category contained methods, they will stay and moved to the list of methods without category.

Example of Custom Function Syntax

Sub MyFunc(Factor1, Factor2: ITimeSeries; Var Output: ITimeSeries; Coef1: Double; Coef2: Double);
Begin
...
End Sub MyFunc;

Function MyFunc(Input, Input1: ITimeSeries; Coef: Double): ITimeSeries;
Var
    Output: ITimeSeries;
Begin
    ...
    Return Output;
End Function MyFunc;