Using previous cell of calculated field to generate the new value in same field

[Qliksense_User]

I am developing a report as above where my pos is getting calculated in the chart. Basically  my POS for FEB is POS for Jan-Principal for Feb and for DEC 2019 it is default value of POS/1e7. So i have used if( amort_monthyear_name='Dec 2019',column(1) , before(column(1))-column(2)). As you can see in the screenshot it is working fine for Jan i.e. 3133.44-68.81=3064.63 whereas for FEB it is doing 3429.33-138.78=3290.55 as i have used before(column(1))  and my requirement is it should do derived POS value of Jan 3064.63- 138.78=2925.85 same for March would be 2925.85-136.27=2789.58

I have also tried to get previous month POS using set analysis by Sum({<amort_monthyear_name={"$(vPreviousMonth)"}>}Pos)/10000000 where vPreviousMonth is my variable for previous month.

The Problem here is when is use this set in KPI I get the exact value however when is use this in pivot table i get 0 values.

Thanks in advance for the help

[IamAlbinAntony · Accepted solution]

In front end use RangeSum() function for doing accumulation. 

[Qliksense_User]

Thanks FruzoCrew i already tried

if( amort_monthyear_name='Dec 2019',Sum(Pos)/10000000,RangeSum(Above(column(3)))-column(1)) and was able to achieve the desired figures in a straight table however, the same expression is not working in a pivot table, I believe maybe RangeSum() would not work in pivot table.

Thanks once again FruzoCrew😊

[IamAlbinAntony]

Try this;

if( amort_monthyear_name='Dec 2019',Sum(Pos)/10000000,RangeSum(before(column(3)))-column(1))