rolly.fs

// this roll why function seems to work on a small 5 x 5 matrix
// but doesn't for bigger 227 x 227 image
// no idea why
let rollArrayY yLength shift (data:'t[]) =
    let shift =
        if shift > 0 then
            shift
        else
            yLength + shift
    let out:'t[] = Array.zeroCreate data.Length
    for i in 0 .. data.Length - 1 do
        let shiftIndex = (i + (shift * yLength)) % data.Length
        out.[shiftIndex] <- data.[i]
    out

// add these as unit test somewhere
let test =
    [| 0. .. 24. |]


let printArrayBy x (data:'t[]) =
    for i in 0 .. data.Length - 1 do
        printf "%f\t" data.[i]
        if i % x = x - 1 then printfn ""
    printfn ""

printArrayBy 5 test

let testy' = rollArrayY 5 2 test 
printArrayBy 5 testy'

let testy'' = rollArrayY 5 -2 testy'
printArrayBy 5 testy''