Slide-rule completeness

A machine is slide rule-complete if said machine can perform any operation that can be simulated by a slide rule of arbitrary length with arbitrary markings.

Slide rule machine

A slide rule machine is an automaton that operates by moving a sliding scale $c$ relative to two fixed scales, $d_{1}$ and $d_{2}$, according to a set of rules.

All unary functions can be simulated by a slide rule machine.