Calculate difference between two n-array products for scatter chart expression

[#1]

Hello everyone,

I need help for an expression:

HOW TO: Calculate difference between two n-array products, where variable n depends on user current selection.

I load data from Excel tables.

For a list of assets I have quarterly performances

asset performance: Ai (i=1 ... 4)

and it's respective benchmark's performance: Bi (i=1 ... 4)   

I want it to calculate the the following formula, which I failed to translate into "Qlikview" expression language (I'm a beginner)

Outperformance:  i=1∏4(Ai) - i=1∏4(Bi)

Here is sample data:

Asset	Period	Performance Fund	Performance Benchmark
xxxx	Quarter 1	1.03	1.02
xxxx	Quarter 2	1.05	1.03
xxxx	Quarter 3	1.06	1.04
xxxx	Quarter 4	1.02	1.03
yyyy	Quarter 1	...	...
yyyy	Quarter 2	...	...
yyyy	...	...	...
yyyy	...	...	...

Thanks very much in advanced for your help!

BTW: "∏" ist the symbol for an n-array (x1 * x2 * x3 *...* xn), similar to the more often seen "∑" for n-array summation (x1 + x2 + x3 .... xn)

Message was edited by: s.spiess