Difference between revisions of "Time index"
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| − | Dynamic simulation time periods are specified in the system variable [[Time]]. To perform dynamic simulation, you must provide a definition for '''Time'''. | + | Dynamic simulation time periods are specified in the system variable [[Time]]. To perform dynamic simulation, you must provide a [[definition]] for '''Time'''. |
To edit the definition of [[Time]], select '''Edit Time''' from the [[Definition menu]] to open the [[Object window]] for '''Time'''. | To edit the definition of [[Time]], select '''Edit Time''' from the [[Definition menu]] to open the [[Object window]] for '''Time'''. | ||
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[[Time]] becomes the index for the array that results from the [[Dynamic]] function. | [[Time]] becomes the index for the array that results from the [[Dynamic]] function. | ||
| − | <tip tilte="Tip"> A model can have only one definition '''Time''' — that is, one set of time periods for | + | <tip tilte="Tip"> A model can have only one definition '''Time''' — that is, one set of time periods for Dynamic functions. Any number of variables in the model can be defined using [[Dynamic]](). |
</Tip> | </Tip> | ||
| − | <tip title= "Tip">A variation, [[Dynamic]][T](), can be used to represent recurrences over indexes other than '''Time''', but placing the index name in square brackets. This provides a way to express secondary recurrences if you’ve already used your | + | <tip title= "Tip">A variation, [[Dynamic]][T](), can be used to represent recurrences over indexes other than '''Time''', but placing the index name in square brackets. This provides a way to express secondary recurrences if you’ve already used your [[Time]] index for sometime else. The dynamic concepts are introduced thoroughly in this chapter using '''Time''', but if you have a loop using a different index, just substitute your other index for [[Time]] in what follows. |
</Tip> | </Tip> | ||
Revision as of 22:07, 17 May 2016
Dynamic simulation time periods are specified in the system variable Time. To perform dynamic simulation, you must provide a definition for Time.
To edit the definition of Time, select Edit Time from the Definition menu to open the Object window for Time.
Time is defined by default as a list of three numbers 0, 1, and 2. You might want to define Time as a list of years, as in the following example.
Time becomes the index for the array that results from the Dynamic function.
Tip
A model can have only one definition Time — that is, one set of time periods for Dynamic functions. Any number of variables in the model can be defined using Dynamic().
Tip
A variation, Dynamic[T](), can be used to represent recurrences over indexes other than Time, but placing the index name in square brackets. This provides a way to express secondary recurrences if you’ve already used your Time index for sometime else. The dynamic concepts are introduced thoroughly in this chapter using Time, but if you have a loop using a different index, just substitute your other index for Time in what follows.
See Also
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