With the Rank button it's very simple to filter the report by top N...
I'm trying to figure out how does it work. What does the BO do behind the scenes...
What steps are carried out in the background
I specifically mean to the cumulative percentage option
In the table above I have City an sales revenue.
I want to filter the table for the cities that made the 50% of the sales reavenu
the answer for that is New york, Houston , LA
Its very easy to achieve that by the build in Rank button.
I want to do It alone with out using the Rank button but I can't astablish it 
My goal is to build an input control (type slider)that I will enter a number beteem 0.1 and 1 and the Rank will change dynamicly
I tried to do it... (the last two columns at thepicture)
I built a variable [running sum] type measure
I built a variable [percentage] =[runningsum]/[total sum in report] and I recice the cumulative percentage column...
But here I am stuck! I am not able to filter the report with this column
Would appreciate help...How do I go from here ?