You can use registered custom-defined functions like native Essbase calculation commands.
To use a registered custom-defined function:
Add the custom-defined function to the calculation script or formula.
For example, to use JSUM, use this calculation script:
"New York" = @JSUM(@LIST(2.3, 4.5, 6.6, 1000.34));
Use this calculation script with the Sample.Basic sample database, or replace “New York” with the name of a member in a test database.
Save the calculation script or formula, and then run it as usual.