Rolling Cumulative Sum
I am trying to find an efficient way to calculate Rolling 3-day CUMULATIVE SUM. I have some for loops that work, but the data sets I am working with are ~500k rows with many more GROUPS, SUBGROUPS and VALUE columns so it takes ~30 minutes to calculate. The example data set is very stripped down and basic. I moved the values into a matrix and that speeds it up a little, but not enough. There is a G...