Former Member

### Trend Model Initial calculations

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.

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Former Member
Jul 07, 2013 at 02:24 PM

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

Thanks,

Naga.

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• Former Member Former Member

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

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
Jul 07, 2013 at 07:03 PM

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.

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• Former Member

HI Borat,

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.