Func<...> vs FSharpFunc<...> (2-arg functions)

gistfile1.fs

#time


let sum (f : 'T -> int -> int) (array : 'T[]) =
    let mutable sum = 0
    for i = 0 to array.Length - 1 do
        sum <- sum + f array.[i] i
    sum



let sum' (f : System.Func<'T, int, int>) (array : 'T[]) =
    let mutable sum = 0
    for i = 0 to array.Length - 1 do
        sum <- sum + f.Invoke(array.[i], i)
    sum

let sum'' (f : ('T * int) -> int) (array : 'T[]) =
    let mutable sum = 0
    for i = 0 to array.Length - 1 do
        sum <- sum + f (array.[i], i)
    sum

let data = [|1..10000000|]

// Real: 00:00:00.283, CPU: 00:00:00.280, GC gen0: 0, gen1: 0, gen2: 0
sum (fun v i -> v + i) data

// Real: 00:00:00.102, CPU: 00:00:00.093, GC gen0: 0, gen1: 0, gen2: 0
sum' (System.Func<_, _, _>(fun v i -> v + i)) data

// Real: 00:00:00.319, CPU: 00:00:00.312, GC gen0: 76, gen1: 0, gen2: 0
sum'' (fun (v, i) -> v + i) data