Ventana software support forum

Hello

I have a very simple question:

¿How do I make a variable to take certain values over time?

For example:

Variable 1 = 5
Variable 2 = 6
Variable 3 = 10

Variable A = during the first period of simulation (e.g. 1 day) takes the value of Variable 1 (5), during the second interval takes the value of Variable 2 (6) and during the last interval takes the value of Variable 3 (10)

thank you!!:D

A lookup table might be the easiest thing here.

Tony.

You can use somthing like

var = IF THEN ELSE(time >= last period, v3,
IF THEN ELSE(time >= second period, v2,v1))

Thank you guys!!

I am going to implement them right now in my model (in a smaller intance), but before it brings me another question:

If I want to assign one value for each day to a variable (and my model runs 120 days) I dont know if there is a faster way to do it. The values itself are not important because next I am going to optimize them under certain policies and hopefuly Vensim will help me to find the "best" values for that variable to take each day...

Any ideas?

For this use VECTOR LOOKUP with Time/Unit Time as the input and a subscript with 120 values - one for each day. This may not optimize very well (lot of parameters, underconstrained, no continuity requirements).

Thank you very much Bob,

I am not sure of how to use Vector lookups and I was hoping that maybe there was another possibility of not using this function but I am seeing that there is not much a choise.

If you can help me with this, please comment on a thread I post today about Lookup functions.... I would really appreaciate it!