Please see Cumulative Window Functions (cum-functions) for the parameters and windowing logic.
Calculate the cumulative weighted sum of X with Y as the weights. The result is a vector of the same length as X. Null values are ignored in the calculation.
$ cumwsum(2.2 1.1 3.3, 4 5 6); [8.8,14.3,34.1] $ cumwsum(1 NULL 1, 1 1 1); [1,1,2]
Related function: wsum