Ventana software support forum

Hi
As we know, stock variable is the integral of flow, if there is a stock with zero slope diagram, what could be the flow anyway?
I meant the Quality diagram in the attached file
best wishes

Sorry, I do not understand what you are asking.

I meant as you can see in the picture, the behavior and structure of the actual quality is clear, suppose the formula of its inflow and outflow is not clear (for actual quality), can you suggest anything (inflow or outflow) that produce actual quality behavior?

So you need some model structure that produces an immediate jump/fall in the stock?

Something like the following should get you started. This causes a jump at time = 10.

some stock = integ (inflow,0)

inflow = if then else ( time = 10, 20 , 0 )

thx
it was a good start, By the way is there any way in vensim that can help us distinguish variable? for example name the constant one? how many constant are there? how many stock and etc.
best wishes

If the stock of actual quality is essentially a step function, its net flow must be a discrete event, like a PULSE.

thanks
I am really delighted to get acquainted with this site and its administers specially Tomfid who always helps me.