what is Forecast and Smooth function mean

[sally]

i need to use a function to forecast,,,,i don't know which function is suitable, i check the vensim, there are two functions i think are suitable, but i didn't know what does it mean, such as, Smooth function=SMOOTH(units,time) , what is time meansi in this equation, i don't know what should i set it , hope some one can give me some suggestions.

thank you ...

[sally]

i still didn't know what is smooth function means?

i have check the help- it said, it is a expo. smooth forecast way, but i don't know how to use it, because in expo. smoothing way, it has the alpha value, and you can control it or revised it, but in smooth function , i can't set up the alpha value?

how to do it

hope someone can help me...

[LAUJJL]

you should read Sterman's book, business dynamics.
There is a chapter on forecasting, that explains the trend and forecast function.
The preceding chapters should be studied too.
Regards.
JJ

[malli]

Find attached a model file that shows how smooth works. I have provided two examples -

1. Doing a smooth without using the vensim formula
2. Doing a smooth with the vensim formula

Hope this helps. Would second what JJ has written - do read Sterman on this.

Regards
Malli

[sally]

hi

thank you for your help, i will read Sterman's book..