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]
.
None
if iter
is empty, else an option value containing the summed T
Override if there is a faster way to compute this sum than
iter.reduceLeftOption
using plus.
Returns the identity element of T
for plus.
Returns the identity element of T
for plus.
This monoid stems from the fact that if X and Y are independent random variables that are normally distributed, then their sum is also normally distributed, with its new mean equal to the sum of two means and variance equal to the sum of two variances. http://en.wikipedia.org/wiki/Sum_of_normally_distributed_random_variables