人工知能的サーバー対ブラウザー(5) - エレファント・ビジュアライザー調査記録

今回は ChatGPT で Python から F# に書き換えたのですが、これはそのままでは動かなくて、かなり書き直しました。

このプログラムの mutable な変数を mutable ではないものに変更するとどうなるか、ということを考えたいのですが、これはなかなか難しそうです。以前このブログで取り上げたときも、とくに何もできていませんでした。今回も同じことになりそうなので、ブログに書く意味があるのか、と思いますがいちおう ChatGPT をちょっと使ったということで書いておくことにします。

open System
open System.Collections.Generic

let formatDecimal (dec: int seq) =
    let declist: int list = Seq.toList dec
    let head = declist.Head
    let tail = declist.Tail |> List.map string |> String.concat ""
    sprintf "%d.%s" head tail

// decimal 型に対するべき乗演算子
let rec ( ** ) (d: decimal) (exp: int) = 
    if exp = 0 then
        1M
    elif exp > 0 then
        d ** (exp - 1) * d
    else
        d ** (exp + 1) / d

// 数値クラスの定義
type Numbers(number: decimal, squareDifference: decimal, scale: int) =
    let mutable number = number
    let mutable squareDifference = squareDifference
    let mutable scale = scale
    member _.Copy() = Numbers(number, squareDifference, scale)
    member _.GetNextDecimalDigit() =
        let two = decimal 2
        Seq.head (seq {
            for dd in [9..-1..0] do
                let zd = decimal dd * (decimal 10 ** -scale)
                let numberSqDiff = number * zd * two + zd * zd
                if numberSqDiff <= squareDifference then
                    number <- number + zd
                    squareDifference <- squareDifference - numberSqDiff
                    scale <- scale + 1
                    yield dd
            })

// 数値ジェネレータークラス
type NumbersGenerator() =
    let generator =
        let number = decimal 0
        let squareDifference = decimal 3
        let nums = Numbers(number, squareDifference, 0)
        seq { while true do yield nums.GetNextDecimalDigit() }
    member _.GetNextDecimalDigit() =
        generator |> Seq.head
    member _.GenerateDecimal() =
        generator

// 数値サーバークラス
type NumbersServer() =
    let mutable currentNumbers =
        Numbers(decimal 0, decimal 3, 0)
    let generatorServer =
        Seq.unfold (fun n -> Some(n, n)) currentNumbers
    member _.GetNumbers() = currentNumbers
    member _.SetNumbers(numbers: Numbers) =
        currentNumbers <- numbers

// 計算クラス
type Calc() =
    let count = 21
    let generator = NumbersGenerator()
    let generatorServer = NumbersServer()
    let mutable resultNumber = decimal 0
    
    member _.RepeatGenerator() =
        for e in [0 .. count - 1] do
            let zd = (decimal (generator.GetNextDecimalDigit())) / (10M ** e)
            resultNumber <- resultNumber + zd
        resultNumber.ToString()

    member _.RepeatServer() =
        for e in [0 .. count - 1] do
            let numbers = generatorServer.GetNumbers()
            let dd = numbers.GetNextDecimalDigit()
            generatorServer.SetNumbers(numbers)
            resultNumber <- resultNumber + (decimal dd) / (10M ** e)
        resultNumber.ToString()

    member _.IterateGenerator() =
        let dec = Seq.take count (generator.GenerateDecimal())
        formatDecimal dec

    member _.IterateServer() =
        let initialNumbers = Numbers(decimal 0, decimal 3, 0)
        let dec = Seq.take count (Seq.unfold (fun (n: Numbers) -> let nn = n.Copy() in Some(nn.GetNextDecimalDigit(), nn)) initialNumbers)
        formatDecimal dec

// テスト出力
printfn "%s" (Calc().RepeatGenerator())
printfn "%s" (Calc().RepeatServer())
printfn "%s" (Calc().IterateGenerator())
printfn "%s" (Calc().IterateServer())