Rank (operator): Difference between revisions

The rank operator was invented by [[Ken Iverson]] 1982, based on [[Arthur Whitney]]'s [[leading axis theory]].<ref>[[Gitte Christensen]] and [[Joey Tuttle]] at [[APL Campfire]]. Aug 1st, 2021.</ref> Whitney was the first to implement the operator for [[SHARP APL]] in 1983. It has been described as "a microcosm of APL history"<ref name="hopl4">[https://dl.acm.org/doi/pdf/10.1145/3386319 Hui, R.K. and Kromberg, M.J., 2020. APL Since 1978. Proceedings of the ACM on Programming Languages.]</ref>, its evolution a progression from [[scalar extension]], which has been in APL since its inception, through leading axis theory to a construct which is a generalisation of scalar extension, [[inner product|inner (matrix) product]], [[outer product]], maplist in LISP, map in modern functional programming languages and the broadcast facility in NumPy.