Fast summation algorithm.
Naive algorithm (one by one).
$(LUCKY Pairwise summation) algorithm. Range must be a finite sliceable range.
$(LUCKY Kahan summation) algorithm.
$(LUCKY Kahan-Babuška-Neumaier summation algorithm). KBN gives more accurate results then Kahan.
$(LUCKY Generalized Kahan-Babuška summation algorithm), order 2. KB2 gives more accurate results then Kahan and KBN.
Precise summation algorithm. The value of the sum is rounded to the nearest representable floating-point number using the $(LUCKY round-half-to-even rule). Result can be differ from the exact value on X86, nextDown(proir) <= result && result <= nextUp(proir). The current implementation re-establish special value semantics across iterations (i.e. handling -inf + inf).
Performs Pairwise summation for random access ranges. Otherwise performs KBN summation of floating point and complex numbers and Kahan summation of user defined types.