Adding stochasticity to variable from .dat file

UniSheep · Post by **UniSheep** » Fri Aug 20, 2010 1:19 am

Hi people,

We are new to Vensim and would like to add stochasticity to an existing rainfall data file. We imported the rainfall data with a .dat file and would like to make it random ...

Anyone having any ideas for us ? ... Would be great!

Thank you ...

bob@vensim.com · Post by **bob@vensim.com** » Fri Aug 20, 2010 9:50 am

You can simply use one of the random functions as in

rainfall = rainfall data + RANDOM NORMAL(-rainfall normal,1e9,0,noise standard deviation,0)

then use rainfall wherever your previous variable was used.

Post by **tomfid** » Fri Aug 20, 2010 3:23 pm

There was a related thread, with examples, a few months ago.
http://www.ventanasystems.co.uk/forum/v ... php?t=4045

Another option would be to take your data, look at its distribution, and then use RANDOM LOOKUP to replicate that. There's probably a lot of autocorrelation at various scales, and seasonality, so you'd have to think about that as well.

Tom