A common type of financial calculation involves a rolling x number of month calculation, like a rolling 12 month net income. In HFM, there were functions and keywords we could use. There are different ways of writing the calculation, but most likely one of these:
HS.Exp "A#R12_NetIncome = A#Net Income.W#Periodic.P#CUR + A#Net Income.W#Periodic.P#CUR-1 + A#Net Income.W#Periodic.P#CUR-2 + A#Net Income.W#Periodic.P#CUR-3 + A#Net Income.W#Periodic.P#CUR-4 + A#Net Income.W#Periodic.P#CUR-5 + A#Net Income.W#Periodic.P#CUR-6 + A#Net Income.W#Periodic.P#CUR-7 + A#Net Income.W#Periodic.P#CUR-8 + A#Net Income.W#Periodic.P#CUR-9 + A#Net Income.W#Periodic.P#CUR-10 + A#Net Income.W#Periodic.P#CUR-11"
OR (assuming a December year end):
HS.Exp "A#R12_NetIncome = A#Net Income.W#YTD + A#Net Income.W#YTD.Y#PRIOR.P#Dec - A#Net Income.W#YTD.Y#PRIOR"
If only a three month rolling amount was needed, use the first approach and just stop after P#CUR-2.
In FCCS, a member formula is a good way to write the calculation (as compared to an insertion rule), but for us HFM converts, how? Essbase has a long list of functions, many of which work just fine with FCCS. The functions we want to look at now are @PRIOR, @RELATIVE, and @CURRMBR. Here are the definitions from Oracle's help website.
@PRIOR - "Returns the nth previous cell member from mbrName, in the sequence XrangeList. All other dimensions assume the same members as the current member. @PRIOR works only within the designated range, and with level 0 members."
@RELATIVE - "Returns all members at the specified generation or level that are above or below the specified member in the database outline."
@CURRMBR - "Returns the member that is currently being calculated in the specified dimension (dimName). This function can be used as a parameter of another function, where that parameter is a single member or a list of members."
So, how do we use these? I don't claim to be the best calc script writer (far from it), but these approaches work for me. For the rolling three month calc, I use this (again, assuming December year end):
IF(@ISMBR("Jan"))
"FCCS_Net Income"->"FCCS_Periodic" + @PRIOR("FCCS_Net Income"->"FCCS_Periodic"->"Dec",1,@RELATIVE("Years",0)) + @PRIOR("FCCS_Net Income"->"FCCS_Periodic"->"Nov",1,@RELATIVE("Years",0));
ELSEIF(@ISMBR("Feb"))
"FCCS_Net Income"->"FCCS_Periodic" + @PRIOR("FCCS_Net Income"->"FCCS_Periodic", 1) + @PRIOR("FCCS_Net Income"->"FCCS_Periodic"->"Dec",1,@RELATIVE("Years",0));
ELSE
"FCCS_Net Income"->"FCCS_Periodic" + @PRIOR("FCCS_Net Income"->"FCCS_Periodic", 1) + @PRIOR("FCCS_Net Income"->"FCCS_Periodic", 2);
ENDIF
Starting with the ELSE part first, the formula gets the current periodic amount and then uses the @PRIOR function to get the first prior and then the second prior month data. This will only work for March to December, though, as the @PRIOR function doesn't wrap around the year like HFM does. So, use the IF or ELSEIF to check for Jan and Feb and for the prior year data points, use the @RELATIVE function within the @PRIOR function to pull from the prior year.
For the rolling 12 month calculation, the above technique could be extended to cover 12 months, but as with the HFM formulas above there is a more elegant way.
"FCCS_Net Income"->"FCCS_YTD" + @PRIOR("FCCS_Net Income"->"FCCS_YTD"->"Dec",1,@RELATIVE("Years",0)) - @PRIOR("FCCS_Net Income"->"FCCS_YTD"->@CURRMBR(Period),1,@RELATIVE("Years",0));
This formula pulls the current month YTD value, adds the prior year December YTD value, and then subtracts the current month, prior year YTD value. The @CURRMBR function is inserting the current month being calculated into the dimension reference for the @PRIOR function. As I type this I'm not sure if this is needed, but as seems to be working I'm leaving it alone.
In closing, Essbase has been around since the early 1990s, so there has been plenty of time to figure out the functions that are needed - us HFM converts just need to learn!
