Get the width of interval X.
If X is empty, wid (X)
is NaN.
If X is unbounded in one or both directions, wid (X)
is
positive infinity.
Accuracy: The result is a tight enclosure of the interval’s actual width.
wid (infsup (2.5, 3.5)) ⇒ ans = 1
See also: @infsup/inf, @infsup/sup, @infsup/rad.
Package: interval