Ventana software support forum

Hi Tom/Colleagues,

I am modelling a situation where changes in the backlog of unmet demand is affecting changes in prices. In this particular case, it seems that negative changes in demand backlog has proportionally stronger impact on prices than positive changes (possibly due to market 'panicking').

Therefore, I am thinking of introducing a 'perceived' changes in the backlog, where positive changes are perceived more slowly (or more weakly) than negative changes. I don't know if this is clear enough. But basically, is there such asymmetrical SMOOTH function built into Vensim? If not, do you have any thoughts on how to implement it (more neatly than just putting in an arbitrary fudge factor)?

Thank you in advance!

Hi

joined a possible way. It uses preferably the formulation of smooth with a level (see the documentation of smooth) . One must use the synthesim and vary the different parameters to see if the formulation makes sense.

The demand is sometimes positive or sometimes nul depending on the mini and maxi parameters.

Regards.

JJ

Hi,

Thanks very much for the reply.

The solution is simple and effective, thanks!
I think I could also use an IF THEN ELSE nested within the SMOOTH with two different delay times. Basically does the same.

Hi

Be careful using an if then else nested within the smooth, and verify how it works. The smooth function hides the previous smooth and may generate strange results. With the level formulation you see exactly what Vensim is doing, but it is maybe possible too to visualize how the smooth function is working by visualizing the hidden variables of the function.

Regards.

JJ