Introduction
What is the time of evaluation? Why is it important to choose the correct one? What happens when you choose the wrong time-step?
Which Time of Evaluation(s) to choose
A lot of the power, and confusion, when setting up a function is based around when to choose to evaluate a function or modelled variable. One important note here is that there will most likely be multiple solutions which will work. To understand where each of the choices fits in within the larger scheme of the model phases please review ......
Suggestion: Each element in Source is evaluated at a different time-step, depending on its .... (what word can be used here?).
-----------------------------------------------
Introduction to function ToE
A few words talking about the two types available - ie. functions & modelled variables.
Functions Time of Evaluation
Anu: The key to choosing the time of evaluation for a function is to consider its usage. For example, if a function is used in a Resource Assessment system, then it is ideally evaluated in the Resource Assessment phase. ((Next sentence: Leave as is))
The way to decide which time of evaluation to choose, is to look at where the function is being used. As an example, if you are using the function in a Resource Assessment System, then ideally the function will be evaluated in the Resource Assessment phase. Likewise, if you are using the function to drive the demand on a time series demand model, then you would want to choose the ordering phase to evaluate the function. In UNCLEAR: In cases where you are using the function in multiple places, you will have to decide whether its appropriate to evaluate the function in multiple phases.
...