Succeeds if X is numeric and M unifies with the median of X; otherwise fails. The median is 0 if the domain of X contains 0; otherwise it is the floating point value which divides the interval into two sub-domains each containing approximately equal numbers of floating point values. Examples:
?- X:: real(1r2,5r3), median(X,M).
M = 0.9128709291752769,
X::real(0.5, 1.6666666666666667).
?- median(42,M).
M = 42.0.
median is also available as an arithmetic function:
?- X::real(1r2,pi), M is median(X).
M = 1.2533141373155003,
X::real(0.5, 3.1415926535897936).