Sam Westrick

@shwestrick.bsky.social

649 Followers 154 Following

assistant professor @NYU Courant CS :: programming languages :: parallel computing :: music :: lead dev of the MaPLe compiler (https://github.com/mpllang/mpl) https://cs.nyu.edu/~shw8119/

fast version of the loop (ARM assembly and profiling counts)

testing code for parallel reduce

same code as before, but zero element `z` is now a function of type `(unit -> 'a) @ portable`

same code for reduce as before, but now with the return value of the reduce annotated as: 'a @ uncontended

dune error message. the entire `reduce ...` recursive call is highlighted with an error: "this value is contended but expected to be uncontended"

a picture of the following OxCaml code:

let rec reduce _par grain g z (lo, hi) f =
let n = hi - lo in
if n <= grain then
let rec loop acc i =
if i >= hi then acc else loop (g acc (f i)) (i+1)
in
loop z lo
else
let mid = lo + n / 2 in
let l, r = Parallel.fork_join2 _par
(fun _par -> reduce _par grain g z (lo, mid) f)
(fun _par -> reduce _par grain g z (mid, hi) f)
in
g l r

aragorn "but it is not this day" gif

screenshot of a temperature plot for my macbook, holding steady at 115 Celcius