Given two streams of doubles (n, an) and (k, ak) of form (count, mean), calculates the mean of the combined stream.
Given two streams of doubles (n, an) and (k, ak) of form (count, mean), calculates the mean of the combined stream.
Uses a more stable online algorithm which should be suitable for large numbers of records similar to: http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Parallel_algorithm
Combines two T instances associatively.
Combines two T instances associatively.
result of combining l and r
Returns an instance of T calculated by summing all instances in
iter in one pass.
Returns an instance of T calculated by summing all instances in
iter in one pass. Returns None if iter is empty, else
Some[T].
instances of T to be combined
None if iter is empty, else an option value containing the summed T
Returns the identity element of T for plus.
Returns the identity element of T for plus.
A monoid to perform moment calculations.