help

[zhouchchun]

in vensim PLE, how to do accumulation

[Administrator]

Use the integ function.

[zhouchchun]

I have simulate ET for 230 days, I want to accumulate them, that is ETS=ET1+ET2+。。。+ET230, I think the integ function can not do it, I don't know how to do it

[tomfid]

If your model is running with a time step of one day, INTEG(ET,0) will be exactly the sum that you describe. A simple check would be to define ET = time and ETSUM = INTEG(ET,0), to see whether you get the anticipated result.

Note that this discrete sum logic is likely to result in inconsistent units of measure.

Tom

[zhouchchun]

thank you for your help, Tom