binned_sum implements fast summing for given bins by calling c-code.
binned_sum(x, bin, nbins = max(bin), ...)# S3 method for default
binned_sum(x, bin, nbins = max(bin), ...)
# S3 method for ff
binned_sum(x, bin, nbins = max(bin), ...)
numeric vector with the data to be summed
integer vector with the bin number for each data point
integer maximum bin number
used by binned_sum.ff
numeric matrix where each row is a bin