how to explore different lookup table?

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memphis15
Junior Member
Posts: 7
Joined: Thu Oct 01, 2015 3:19 pm
Vensim version: PLE

how to explore different lookup table?

Post by memphis15 »

hi all,

for example, i have a few variables, each of them may be assigned value from a number of lookup tables, so i would like to have a sensitivity analysis of all the combination of the these lookup tables.

I have tried to write a contact variable into the lookup table, but the vensim does not allow me to do this.

any suggestions? it will be time-consuming and silly to change the lookup table manually each time.

thanks,

Yong
tomfid
Administrator
Posts: 4005
Joined: Wed May 24, 2006 4:54 am

Re: how to explore different lookup table?

Post by tomfid »

You can use the VECTOR LOOKUP function to parameterize your lookup points as an array of constants.

Or, you can create a function to shift or stretch your lookup results, according to a few parameters. For example:

effect of price = price sensitivity * price effect lookup( price/normal price ) + (1-price sensitivity)

where price sensitivity is a parameter, normally = 1, which you can vary to intensify or weaken the price effect. You could build on this idea make the relationship multiplicative or exponential, add additional parameters, etc.
memphis15
Junior Member
Posts: 7
Joined: Thu Oct 01, 2015 3:19 pm
Vensim version: PLE

Re: how to explore different lookup table?

Post by memphis15 »

thank you so much!
memphis15
Junior Member
Posts: 7
Joined: Thu Oct 01, 2015 3:19 pm
Vensim version: PLE

Re: how to explore different lookup table?

Post by memphis15 »

it seems both of your options could deal with lookup tables which are mathemtically correlated. for example, by the VECTOR LOOKUP function, tables from mode 1-9 are actually some functions from table 0. I am wondering if there are convenient way to switch among lookup tables which do not have too much correlation? i guess this should be a very common need, for example, to make prediction under different future scenarios?
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