Stable Numerics Subroutine Library
Programming Reference Manual
Version 1.1 DD-00006-011

3.5 Real Triplex Arithmetic TR

Triplex arithmetic TR  is the equivalent of interval arithmetic IR  but with aside from the infinimum x , supremum x an additional midpoint value x is contained in a triplex that captures the default floating point value achieved through standard nearest rounding. As such

x ≤x ≤x ∀X ∈TR

3.5.1 Empty Triplex