Piecewise linear function
In mathematics, a piecewise linear or segmented function is a real-valued function of a real variable, whose graph is composed of straight-line segments. == Definition == A piecewise linear function is a function defined on a (possibly unbounded) interval of real numbers, such that there is a collection of intervals on each of which the function is an affine function.
Source: Wikipedia — Piecewise linear function (CC BY-SA 4.0)