Returns a vector of cumulative sums of the input values,
running in reverse order. That is, the ith entry in the output
is the sum of entries i to n in the input,
where n is the length of the input.
Usage
revcumsum(x)
Arguments
x
A numeric or complex vector.
Value
A vector of the same length and type as x.
Details
This low-level utility function is a faster alternative to
rev(cumsum(rev(x)))
under certain conditions.
It computes the reverse cumulative sum of the entries of x.
If y <- revcumsum(x), then y[i] = sum(x[i:n]) where
n = length(x).
This function should not be used if x could contain NA
values: this would lead to an error.