| revcumsum {spatstat.utils} | R Documentation |
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.
revcumsum(x)
x |
A numeric or complex vector. |
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.
A vector of the same length and type as x.
Adrian Baddeley Adrian.Baddeley@curtin.edu.au.
revcumsum(1:5) rev(cumsum(rev(1:5))) x <- runif(1e6) system.time(rev(cumsum(rev(x)))) system.time(revcumsum(x))