Trend Model Initial calculations

[Former Member]

Hi Experts,

Strategy 21 - I used in the forecast profile But the calculation of the 'Initial' periods are wrong as per the SAP given formulas.

Could you please let me know how the values are calculating in the below chart. SAP is calculating differently and it is not considering the model INITIAL formulas.

These are the formulas SAP has given for the INITIAL period calculation. As per these below formulas the TREND and Basic Values are wrong in the above screen which I marked in Red. Please some can give me the clarity in this regards.

[Former Member · Accepted solution]

Dear Sumanth,

Whatever the formulas provided by SAP its correct only.

For trend atleast we have to use 2/3 seasons history(1 season=12 months).

I tested It,its working for me.

Example:

here hist(1)=200,hist(2)=200,hist(3)=400....Trend=hist(3)-hist(1)/2=400-200/2=100

Basic value=hist1+2+3/3+trend....Basic=200+300+400/3+100=400

I hope this will help you.

Thanks,

Naga.

[Former Member · Accepted solution]

Hi Naga Reddy,

Thanks for your reply..

I think the first bucket in your screen shot left to calculate the Trend and Basic Value i.e is M08.2011.

I think as per the formula we have to consider first 3 buckets, that means M08.2011, M09.2011 and M10.2011. You are considering from M10.2011 and it is not a first bucket according to the formula.

[Former Member · Accepted solution]

This post may be useful. Per help.com, the initial periods used is 3 but parameters are available to change this

http://scn.sap.com/message/6407004#6407004

seems this wasn't answered too.

Try running the background and see if the results are any different. Check the results at same conditions in the selection as was used in background agg level.

Pasting this for general reference. source. help.sap.com

The system uses a fixed number of historical values to carry out model initialization. This number depends on the forecast model:

Model	Fixed number of historical values used for initialization
Constant	1
Trend	3
Seasonal	1 season
Seasonal trend	3 + 1 season
Automatic model selection with selection with seasonal test	2 seasons
Automatic model selection with seasonal + trend tests	3 + 2 seasons
2nd-order exponential smoothing	3

[Former Member]

possible reason..

Per the values as seen on screen, the basic value initial should be 2740. It is higher which means the average is most probably calculated using the SUM / NUMER logic rather than AVG logic and this is happening bottoms up. So 0's if any at most detailed level are ignored in the calculation

Also check the setting 0 allowed for cleansed history in the planning area.. i.e. are you making a distinction between zero and blanks.

Regards

Borat.

[Former Member]

HI Borat,

Thanks many for your reply..

The KF which i am using for the 'Clean History is 'Not allowed Zero' for the PA.

For the KF Clean History 'Zero allowed' is unticked in the PA.

Just want to know is that the reason which is not calculating the INITIAL values for Trend and Basic Values. I don't think so this the reason.

Can anyone Please help.

As per the above SAP formula the Basic value should be

2740  and Trend value should be 459 for the First Initial Periods.

Thanks,