lookup

[oludot5]

hi there,

Please, is there a way I can create a lookup to accept the time step as the input?say, for example, A= 8 for time 1, A= 6 for time 2.....

[Administrator]

Try this (you will need to add more x/y pairs if you want a lookup for every time in the model).

Code: Select all

lookup table ( (1,8) , (2,6) )

[tomfid]

http://www.vensim.com/documentation/usr08.htm

[oludot5]

tnx, but what variable name do I give the time step (round of simulation) in the lookup function...I still dont get how the lookup variable will accept each iterative time count as the input to produce the lookup output

[Administrator]

Is this what you mean?

Code: Select all

lookup table ( (1,8) , (2,6) )

lookup result = lookup table ( time )

[oludot5]

thanks!

[tomfid]

Since Vensim is oriented toward continuous time simulation, there is no variable for the iteration number (or round) of the simulation. There's Time, which is sliced into TIME STEPs. If your TIME STEP = 1, it's easy to work out the "round", though this its typically not a good choice to rely on such a discrete count, because it will change if you change TIME STEP, which one should generally do as a test for numerical stability. Certainly there are times where discrete time is useful, but it can be tricky to rely on it in general.