Ventana software support forum

Hello!

I was wondering if anybody has a model who has a vector lookup function included that can upload because I tried to use this function in one of my models but I have not figured out how it works and the literature (webpages and manual) I revised have not helped me.. yet..

I would really appreciate it!!

This is a simple example that does what you want from the other thread.

Thank you Bob,

I downloaded the model and it makes perfect sense now (refereing to the structure and the inputs). Just one observation: when I try to run it a compilation error appears: "Missing a closing parenthesis on a lookup table call"

The cursor points here(*):

var over time= VECTOR LOOKUP(vec[T1],*Time/Unit Month, INITIAL TIME/Unit Month, FINAL TIME/Unit Month, 2).

I tried, based on your example, some other examples that should work, but it allways appear the compilation error with the same message. I review the example explained on http://www.vensim.com/documentation/html/22779.htm
but even so I get the same message.

I am not sure but can it be because I am running Vensim DSS version 5.5b? I am running out of options that could explain what is happening :S

But anyways, thanks lot (again!)!

VECTOR LOOKUP was introduced in 5.6c so you won't be able to use it.

Bob,

Thank you very much anyway.
Hope my saving let me buy the latest version this year

You can create a vector lookup using subscripts. It's not as convenient, but works. Here's one approach (not necessarily the best way to do the interpolation, but it works):

interval weight[xNext]=
MAX(0,MIN(1, (x input-x vals[xPrev])/(x vals[xNext]-x vals[xPrev]) )) ~~|
interval weight[x1]=
1
~
~ |

vec:
(x1-x5)
~
~ |

x input=
Time
~
~ |

x vals[vec]=
10,25,30,35,50
~
~ |

x weight[xPrev]=
MIN(interval weight[xPrev],1-interval weight[xNext]) ~~|
x weight[x5]=
interval weight[x5]
~
~ |

xNext:
(x2-x5) -> xPrev
~
~ |

xPrev:
(x1-x4) -> xNext
~
~ |

y output=
SUM(x weight[vec!]*y vals[vec!])
~
~ |

y vals[vec]=
1,3,2,5,4
~
~ |