Generic piecewise function trait and impls
pcw_fn is a library for handling piecewise defined functions (or other "piecewise data") generically.
Currently the PcwFn trait the library is built around is implemented for
a single type: VecPcwFn. This type represents a piecewise function f given
by a collection of jump positions and functions such that
╭ f₁(x) if x < x₀
│ f₂(x) if x₀ ≤ x < x₁
f(x) = ┤ f₃(x) if x₁ ≤ x < x₂
│ ⋮ ⋮
╰ fₙ(x) if xₙ ≤ x
for all x ∈ X where
f₁,...,fₙ : X -> Y, and
x₀ < x₁ < ... < xₙ
from some strictly totally ordered set X (so X is Ord). Note that for most functionality it's not required that the funcs actually behave like a function so the type can be used very well for "non-functional" funcs.
It's trivial to add impls backed by other types like SmallVec or StaticVec.