The PRIMITIVES signature

Overview

The PRIMITIVES signature provides a few “primitive” operations for parallel evaluation.

Interface

val par : (unit → 'a) * (unit → 'b) → ('a * 'b)
val parallelFor : int * int → (int → unit) → unit

Values

val par : (unit → 'a) * (unit → 'b) → ('a * 'b)

par (f, g) evaluates $f$ and $g$ in parallel. It is logically equivalent to $(f(), g())$.

val parallelFor : int * int → (int → unit) → unit

parallelFor (lo, hi) f applies $f$ to every index in the half-open range $[lo, hi)$, in parallel, and returns once all of them have finished. It is run for its effects; $f$ returns nothing. The iterations must be independent: they may run in any order and at the same time, so $f$ must not rely on one iteration having happened before another, and no two of them may write to the same place. Prefer tabulate wherever it fits, which builds a sequence from a function of the index without any mutation. No lab in this course needs parallelFor.