Update Active Variables
This function updates all the variables that are required by all the active World Variables.
An active World Variable is a variable that is being referenced in the current session.
For example, all World Variables that are in the Default World State are active since they have been referenced in the current session and
therefore their components have been constructed in memory. [If a component is not
referenced by any other component it is automatically removed from memory.]
This function updates the variables in the following order:
- External Data Variables;
- Computed Data Variables;
- World Variable Data Variables;
- World Variables.
Only after all the other variables have been update can a World Variable
update its own data structures. For example, a Sovereign Yield Curve must have all the data for its base yield curve before it can calculate its
zero coupon yield curve.