Compute per-group cumulative sums

cumsum_g_no_NA(col, first_indices)

Arguments

col	vector to cumulative sum
first_indices	numeric index of first index in each group

per-group cumulative sum


v <- c(2, 3, 1, 4, 5)
fi <- c(1, 1, 3, 3, 3)
cumsum_g_no_NA(v, fi)
#> [1]  2  5  1  5 10