// Learn more about F# at http://fsharp.org
// See the 'F# Tutorial' project for more help.

module problema1 =

    open System

    let contFraction (arr : int[]) =

        let mutable arrAux = Array.map (fun x -> float x) arr

        let mutable arrAuxRev = Array.rev arrAux

        let mutable sum = 1.0 / arrAuxRev.[0]

        for i = 1 to arrAuxRev.Length-2 do
            sum <- 1.0 / (sum+arrAuxRev.[i])

        sum <- sum + arrAuxRev.[arrAuxRev.Length-1]

        printfn "%f" sum

    let mainP1() =
        contFraction [|3; 7; 15; 1; 292; 1|]

// ===================================

module problema1b =

    let contFraction (arr : int[]) =

        let mutable arrAux = Array.map (fun x -> float x) arr

        let mutable arrAuxRev = Array.rev arrAux

        let mutable sum = Array.reduce(fun x y -> y + 1.0 / x) arrAuxRev

        printfn "%f" sum

    let mainP1b() =
        contFraction [|3; 7; 15; 1; 292; 1|]

// ===================================

module problema3 =

    let multiplyI (a:int[,]) (b:int[,]) =
        let n = a.GetLength(0)
        let m = a.GetLength(1)
        let p = b.GetLength(0)
        let q = b.GetLength(1)
        if (m <> p) then
            Array2D.zeroCreate 1 1
        else
            let c = Array2D.init n q (fun x y -> 0)
            for i=0 to n-1 do
                for j=0 to p-1 do
                    for k=0 to m-1 do
                        c.[i,j] <- c.[i,j] + a.[i,k] * b.[k,j]
            c

    let mainP3() =
        let rand = System.Random()
        let a = Array2D.init 2 3 (fun x y -> rand.Next(10))
        let b = Array2D.init 3 4 (fun x y -> rand.Next(10))
        let c = multiplyI a b
        printfn "A = \n%A\n\nB = \n%A\n\nA * B = \n%A" a b c
        let d = multiplyI b a
        printfn "\nB * A = \n%A" d

// ===================================

// ===================================

module problema3b =

    let multiplyF (a:int[,]) (b:int[,]) =
        let n = a.GetLength(0)
        let m = a.GetLength(1)
        let p = b.GetLength(0)
        let q = b.GetLength(1)
        if (m <> p) then
            Array2D.zeroCreate 1 1
        else
            let compute ai bj =
                let row = a.[ai, *]
                let column = b.[*, bj]
                let prod = Array.map2 (fun x y -> x + y) row column
                let p = Array.reduce (fun x y -> x + y) prod
                p
            let c = Array2D.init n q (fun x y -> compute x y)
            c

    let mainP3b() =
        let rand = System.Random()
        let a = Array2D.init 2 3 (fun x y -> rand.Next(10))
        let b = Array2D.init 3 4 (fun x y -> rand.Next(10))
        let c = multiplyF a b
        printfn "A = \n%A\n\nB = \n%A\n\nA * B = \n%A" a b c
        let d = multiplyF b a
        printfn "\nB * A = \n%A" d


[<EntryPoint>]
let main argv =
    problema1.mainP1()
    problema1b.mainP1b()
    problema3.mainP3()
    problema3b.mainP3b()
    0 // return an integer exit code