具有障碍物覆盖算法的网格

Grid with obstacles coverage algorithm

我必须找到一个机器人代理的算法来执行以下操作(对不起,我真的不知道怎么称呼它):

目标是在 2000 步中获得最多的胡萝卜。

有 lazy/easy 的方法吗?

到目前为止,我有点迷茫,因为它不是解决迷宫的问题。它会是一种洪水填充算法吗?有没有更简单的?

我不一定要搜索 "solve" 问题,而是尽可能地寻找一个简单的近似值

要找到一个具有完美策略的机器人实现确实有点工作,因为它不知道食物来源的位置和数量。

机器人的任何给定策略可能不会在每个 运行 中产生最大可能的收获。所以问题是,哪种策略在多次模拟中最成功 运行s.

要为正方形类型(P(fastFood)、P(slowFood)、P(obstacle))的给定统计分布找到合适的策略,可能会想到以下想法:

让 Bot(npatch) 成为一个寻找 npatch 食物点的机器人。其策略是先吃掉在第一个食物块中找到的东西,然后再搜索第二个食物块,依此类推。当它访问 npatch 食物来源(或没有找到更多的食物补丁)时,它 returns 找到第一个并重新收获。

这个 class 的机器人 (Bot(npatch)) 现在可以在统计上相关的模拟次数 运行 中相互竞争。最佳机器人是比赛的获胜者。

这种方法可以被认为是受遗传算法的启发,但没有混合任何基因,而是简单地迭代所有基因(1..npatch)。也许有人有想法如何将这个想法转化为完全遗传算法。这可能涉及转向 Bot(npatch,searchStrategy),然后使用多个基因来应用遗传算法。

每当模拟参数发生变化时,就必须重复比赛,显然这取决于世界上食物块的数量,如果某些食物可能会或可能不会再去寻找另一个食物块。补丁已经知道了。

下面的代码是用 F# 编写的,是该问题的模拟器(如果我的所有要求都正确,那就是...)。写一个新的机器人就像写一个函数一样简单,然后传递给模拟器。

对于那些想尝试自己的机器人的人来说,这是我的彩蛋。

我写的 2 个机器人被称为 "marvinRobot",它做 Marvin 会做的事情,"lazyRobot" 一个机器人在它找到的第一个食物来源上扎营。

type Square =
    | Empty
    | Obstacle
    | Food of float * (float -> float) // available * growth
    | Unknown

let rnd = new System.Random()
let grow p a =
    let r = rnd.NextDouble()
    if r < p then a + 1.0
    else a

let slowGrowth a = grow 0.01 a
let fastGrowth a = grow 0.02 a

let eatPerTick = 1.0 
let maxFoodPerSquare = 20.0

let randomPick values =
    let count = List.length values
    let r = rnd.Next(0,count-1)
    values.Item(r)

type World = Square[,]

let randomSquare pobstacle pfood =
    let r = rnd.NextDouble()
    match r with
    | x1 when x1 < pobstacle -> Obstacle
    | x2 when x2 < (pobstacle + pfood) && x2 >= pobstacle -> 
        Food(rnd.NextDouble() * maxFoodPerSquare, randomPick [slowGrowth; fastGrowth])
    | _ -> Empty

let createRandomWorld n pobstacle pfood = 
    Array2D.init n n (fun col row -> randomSquare pobstacle pfood)

let createUnknownWorld n =
    Array2D.create n n Unknown

type Position = { Column : int; Row : int }

type RoboState = { Memory : Square[,]; Pos : Position; Heading : Position }
type RoboAction = 
    | TurnRight
    | TurnLeft
    | MoveOne
    | Eat
    | Idle

type RoboActor = World -> RoboState -> RoboAction

let right heading : Position =
    match heading with
    | { Column = 0; Row = 1 } -> { Column = -1; Row = 0 }
    | { Column = -1; Row = 0 } -> { Column = 0; Row = -1 }
    | { Column = 0; Row = -1 } -> { Column = 1; Row = 0 }
    | { Column = 1; Row = 0 } -> { Column = 0; Row = 1 }
    | _ -> failwith "Invalid heading!"

let left heading : Position =
    match heading with
    | { Column = -1; Row = 0 } -> { Column = 0; Row = 1 }
    | { Column = 0; Row = -1 } -> { Column = -1; Row = 0 }
    | { Column = 1; Row = 0 } -> { Column = 0; Row = -1 }
    | { Column = 0; Row = 1 } -> { Column = 1; Row = 0 } 
    | _ -> failwith "Invalid heading!"

let checkAccess n position =
    let inRange v = v >= 0 && v < n
    (inRange position.Column) && (inRange position.Row)

let tickWorld world =
    world 
    |> Array2D.map 
        (fun sq -> 
            match sq with 
            | Empty -> Empty 
            | Obstacle -> Obstacle 
            | Food(a,r) -> Food(min (r a) maxFoodPerSquare, r)
            | Unknown -> Unknown
        )

let rec step robot world roboState i imax acc = 
    if i < imax then
        let action = robot world roboState
        match action with
        | TurnRight ->
            let rs1 = { roboState with Heading = right roboState.Heading }
            let wrld1 = tickWorld world
            step robot wrld1 rs1 (i+1) imax acc
        | TurnLeft ->
            let rs1 = { roboState with Heading = left roboState.Heading }
            let wrld1 = tickWorld world
            step robot wrld1 rs1 (i+1) imax acc
        | MoveOne ->
            let rs1 =
                let c = 
                    { Column = roboState.Pos.Column + roboState.Heading.Column 
                      Row = roboState.Pos.Row + roboState.Heading.Row
                    }
                if checkAccess (Array2D.length1 world) c 
                then 
                    match world.[c.Column,c.Row] with
                    | Obstacle -> 
                        roboState.Memory.[c.Column,c.Row] <- Obstacle
                        roboState
                    | _ -> { roboState with Pos = c }
                else
                    roboState
            let wrld1 = tickWorld world
            step robot wrld1 rs1 (i+1) imax acc
        | Eat -> 
            let eat,acc1 = 
                match world.[roboState.Pos.Column,roboState.Pos.Row] with
                | Empty -> Empty,acc
                | Obstacle -> Obstacle,acc
                | Food(a,r) -> 
                    let eaten = if a >= eatPerTick then eatPerTick else 0.0
                    printfn "eating %f carrots" eaten
                    Food(a - eaten, r),eaten + acc
                | Unknown -> Unknown,acc
            world.[roboState.Pos.Column,roboState.Pos.Row] <- eat
            let wrld1 = tickWorld world
            step robot wrld1 roboState (i+1) imax acc1
        | Idle ->
            step robot (tickWorld world) roboState (i+1) imax acc
    else
        acc

let initRoboState n = 
    {   Memory = createUnknownWorld n; 
        Pos = { Column = 0; Row = 0;}; 
        Heading = {Column = 1; Row = 0}
    }

let simulate n pobstacle pfood imax robot =
    let w0 = createRandomWorld n pobstacle pfood
    let r0 = initRoboState n
    printfn "World: %A" w0
    printfn "Initial Robo State: %A" r0
    let result = step robot w0 r0 0 imax 0.0
    printfn "Final Robo State: %A" r0
    result

// Not that Marvin would care, but the rule for this simulator is that the 
// bot may only inspect the square in the world at the current position.
// This means, IT CANNOT SEE the neighboring squares.
// This means, that if there is a obstacle next to current square, 
// it costs a simulation tick to find out, trying to bump against it.
// Any access to other squares in world is considered cheating!
// world is passed in spite of all said above to allow for alternate rules.
let marvinRobot world roboState =
    Idle

// Tries to find a square with food, then stays there, eating when there is something to eat.
let lazyRobot (world : World) (roboState : RoboState) =
    let search() =
        let status action : RoboAction =
            match action with
            | TurnLeft -> printfn "%A TurnLeft at %A (heading: %A)" world.[roboState.Pos.Column,roboState.Pos.Row] roboState.Pos roboState.Heading
            | TurnRight -> printfn "%ATurnRight at %A (heading: %A)" world.[roboState.Pos.Column,roboState.Pos.Row]  roboState.Pos roboState.Heading
            | MoveOne -> printfn "%A MoveOne at %A (heading: %A)" world.[roboState.Pos.Column,roboState.Pos.Row] roboState.Pos roboState.Heading
            | Idle -> printfn "%A Idle at %A (heading: %A)" world.[roboState.Pos.Column,roboState.Pos.Row] roboState.Pos roboState.Heading
            | Eat -> printfn "%A Eat at %A (heading: %A)" world.[roboState.Pos.Column,roboState.Pos.Row] roboState.Pos roboState.Heading
            action
        let neighbors = 
            [ roboState.Heading, MoveOne;
              (roboState.Heading |> right),TurnRight;
              (roboState.Heading |> left),TurnLeft;
              (roboState.Heading |> right |> right),TurnRight
            ]
            |> List.map (fun (p,a) -> (p.Column,p.Row),a)
            |> List.map (fun ((c,r),a) -> (roboState.Pos.Column + c,roboState.Pos.Row + r),a)
            |> List.filter (fun ((c,r),a) -> checkAccess (Array2D.length1 world){Position.Column = c; Row = r})
            |> List.sortBy (fun ((c,r),a) -> match roboState.Memory.[c,r] with | Food(_,_) -> 0 | Unknown -> 1 | Empty -> 2 | Obstacle -> 3)
            |> List.map (fun ((c,r),a) -> { Column = c; Row = r},a)
        if neighbors.IsEmpty then failwith "It's a trap!" // can happen if bot is surrounded by obstacles, e.g.  in a corner
        else
            let p,a = neighbors.Head
            status a
    roboState.Memory.[roboState.Pos.Column, roboState.Pos.Row] <- 
            world.[roboState.Pos.Column,roboState.Pos.Row]
    match world.[roboState.Pos.Column,roboState.Pos.Row] with
    | Food(a,_) -> 
        printfn "Found food at %A" roboState.Pos
        Eat
    | _ -> 
        search()

//simulate 10 0.1 0.05 2000 marvinRobot
simulate 10 0.1 0.1 2000 lazyRobot

最后一个提示:如果您使用 0.0 个食物块进行模拟,您的机器人应该已经访问了地图上的所有方块。如果它做不到这一点,那它肯定不是一个好的机器人 ;)