optimized "init" and "create"

[goswinr]

this versions of "init" without the seq expression runs about 15 times faster for me. my comparison:
is there a reason to not do it like this ?

time

let createSeq n x = new ResizeArray<_> (seq { for _ in 1 .. n -> x })

let createLoop (n: int) x =
let arr = ResizeArray<_>(n)
for i=0 to n-1 do arr.Add x
arr

for i=0 to 1000 do // Real: 00:00:00.506, CPU: 00:00:00.530, GC Gen0: 14, Gen1: 3, Gen2: 3
let r = createSeq 1000 4.4
r.Count |> ignore

for i=0 to 1000 do // Real: 00:00:00.016, CPU: 00:00:00.031, GC Gen0: 1, Gen1: 1, Gen2: 1
let r = createLoop 1000 4.4
r.Count |> ignore

[ovatsus]

These two functions were copied from the F# PowerPack, probably no one bothered to optimize them, but I don't see any problem on using the loop instead. Probably the main perf difference was because the capacity was not being initialized

[mausch]

Thanks!