MATLAB言語で学ぶ「Java言語で学ぶデザインパターン入門」ノート #10 Strategy

概要

Strategy パターンは、アルゴリズムを容易に入れ替えられる、デザインパターンの一つである。

ソースコード

Hand.m

classdef Hand < handle
    properties (Access = public, Constant)
        HANDVALUE_GUU(1,1) double {mustBeInteger} = 0;
        HANDVALUE_CHO(1,1) double {mustBeInteger} = 1;
        HANDVALUE_PAA(1,1) double {mustBeInteger} = 2;
        hand(1,3) Hand = [...
            Hand(Hand.HANDVALUE_GUU),...
            Hand(Hand.HANDVALUE_CHO),...
            Hand(Hand.HANDVALUE_PAA)...
        ];
    end
    properties (Access = private, Constant)
        name(1,3) cell = {
            'グー',...
            'チョキ',...
            'パー',...
        };
    end
    properties (Access = private)
        handvalue(1,1) double {mustBeInteger};
    end
    methods (Access = private)
        function obj = Hand(handvalue)
            arguments (Input)
                handvalue(1,1) double {mustBeInteger}
            end
            arguments (Output)
                obj(1,1) Hand
            end
            obj.handvalue = handvalue;
        end
        function out = fight(obj, h)
            arguments (Input)
                obj(1,1) Hand
                h(1,1) Hand
            end
            arguments (Output)
                out(1,1) double {mustBeInteger}
            end
            if obj.handvalue == h.handvalue
                out = 0;
            elseif rem((obj.handvalue + 1), 3) == h.handvalue
                out = 1;
            else
                out = -1;
            end
        end
    end
    methods (Access = public, Static)
        function out = getHand(handvalue)
            arguments (Input)
                handvalue(1,1) double {mustBeInteger}
            end
            arguments (Output)
                out(1,1) Hand
            end
            out = Hand.hand(handvalue);
        end
    end
    methods (Access = public)
        function out = isStrongerThan(obj, h)
            arguments (Input)
                obj(1,1) Hand
                h(1,1) Hand
            end
            arguments (Output)
                out(1,1) logical
            end
            out = obj.fight(h) == 1;
        end
        function out = isWeakerThan(obj, h)
            arguments (Input)
                obj(1,1) Hand
                h(1,1) Hand
            end
            arguments (Output)
                out(1,1) logical
            end
            out = obj.fight(h) == -1;
        end
        function out = toString(obj)
            arguments (Input)
                obj(1,1) Hand
            end
            arguments (Output)
                out(1,:) char {mustBeTextScalar}
            end
            out = Hand.name{obj.handvalue};
        end
    end
end

Strategy.m

classdef (Abstract) Strategy < handle
    methods (Access = public, Abstract)
        out = nextHand(obj)
        study(obj, win)
    end
end

WinningStrategy.m

classdef WinningStrategy < Strategy
    properties (Access = private)
        random(1,1) RandStream = matlab.lang.invalidHandle('RandStream')
        won(1,1) logical = false
        prevHand(1,1) Hand = matlab.lang.invalidHandle('Hand')
    end
    methods (Access = public)
        function obj = WinningStrategy(seed)
            arguments (Input)
                seed(1,1) double {mustBeInteger}
            end
            arguments (Output)
                obj(1,1) WinningStrategy
            end
            obj.random = RandStream('twister', 'Seed', seed);
        end
        function out = nextHand(obj)
            arguments (Input)
                obj(1,1) WinningStrategy
            end
            arguments (Output)
                out(1,1) Hand
            end
            if ~obj.won
                obj.prevHand = Hand.getHand(randi(obj.random, length(Hand.hand)));
            end
            out = obj.prevHand;
        end
        function study(obj, win)
            obj.won = win;
        end
    end
end

ProbStrategy.m

classdef ProbStrategy < Strategy
    properties (Access = private)
        random(1,1) RandStream = matlab.lang.invalidHandle('RandStream')
        prevHandValue(1,1) double {mustBeInteger} = 1
        currentHandValue(1,1) double {mustBeInteger} = 1
        history(3,3) double {mustBeInteger} = [...
            [1, 1, 1];...
            [1, 1, 1];...
            [1, 1, 1];...
        ]
    end
    methods (Access = public)
        function obj = ProbStrategy(seed)
            arguments (Input)
                seed(1,1) double {mustBeInteger}
            end
            arguments (Output)
                obj(1,1) ProbStrategy
            end
            obj.random = RandStream('twister', 'Seed', seed);
        end
        function out = nextHand(obj)
            arguments (Input)
                obj(1,1) ProbStrategy
            end
            arguments (Output)
                out(1,1) Hand
            end
            bet = randi(obj.random, obj.getSum(obj.currentHandValue));
            if bet <= obj.history(obj.currentHandValue, 1)
                handvalue = 1;
            elseif bet <= obj.history(obj.currentHandValue, 1) + obj.history(obj.currentHandValue, 2)
                handvalue = 2;
            else
                handvalue = 3;
            end
            obj.prevHandValue = obj.currentHandValue;
            obj.currentHandValue = handvalue;
            out = Hand.getHand(handvalue);
        end
        function study(obj, win)
            if (win)
                obj.history(obj.prevHandValue, obj.currentHandValue) = obj.history(obj.prevHandValue, obj.currentHandValue) + 1;
            else
                obj.history(obj.prevHandValue, rem(obj.currentHandValue, 3) + 1) = obj.history(obj.prevHandValue, rem(obj.currentHandValue, 3) + 1) + 1;
                obj.history(obj.prevHandValue, rem(obj.currentHandValue + 1, 3) + 1) = obj.history(obj.prevHandValue, rem(obj.currentHandValue + 1, 3) + 1) + 1;
            end
        end
    end
    methods (Access = private)
        function out = getSum(obj, hv)
            out = 0;
            for k = 1:3
                out = out + obj.history(hv, k);
            end
        end
    end
end

Player.m

classdef Player < handle
    properties (Access = private)
        name(1,:) char
        strategy %(1,1) Strategy = matlab.lang.invalidHandle('Strategy')
        wincount(1,1) double
        losecount(1,1) double
        gamecount(1,1) double
    end
    methods (Access = public)
        function obj = Player(name, strategy)
            arguments (Input)
                name(1,:) char
                strategy(1,1) Strategy
            end
            arguments (Output)
                obj(1,1) Player
            end
            obj.name = name;
            obj.strategy = strategy;
        end
        function out = nextHand(obj)
            arguments (Input)
                obj(1,1) Player
            end
            arguments (Output)
                out(1,1) Hand
            end
            out = obj.strategy.nextHand();
        end
        function win(obj)
            arguments (Input)
                obj(1,1) Player
            end
            obj.strategy.study(true);
            obj.wincount = obj.wincount + 1;
            obj.gamecount = obj.gamecount + 1;
        end
        function lose(obj)
            arguments (Input)
                obj(1,1) Player
            end
            obj.strategy.study(false);
            obj.losecount = obj.losecount + 1;
            obj.gamecount = obj.gamecount + 1;
        end
        function even(obj)
            arguments (Input)
                obj(1,1) Player
            end
            obj.gamecount = obj.gamecount + 1;
        end
        function out = toString(obj)
            arguments (Input)
                obj(1,1) Player
            end
            arguments (Output)
                out(1,:) char
            end
            out = ['[', obj.name, ':', num2str(obj.gamecount), ' games, ', num2str(obj.wincount), ' win, ', num2str(obj.losecount), ' lose', ']'];
        end
    end
end

main.m

function main(randomseed1, randomseed2)
if nargin ~= 2
    disp('Usage: main randomseed1 randomseed2');
    disp('Example: main 314 15');
    return;
end

seed1 = str2double(randomseed1);
seed2 = str2double(randomseed2);
player1 = Player('Taro', WinningStrategy(seed1));
player2 = Player('Hana', ProbStrategy(seed2));
for k = 1:10000
    nextHand1 = player1.nextHand();
    nextHand2 = player2.nextHand();
    if nextHand1.isStrongerThan(nextHand2)
        disp(['Winner: ', player1.toString()]);
        player1.win();
        player2.lose();
    elseif nextHand2.isStrongerThan(nextHand1)
        disp(['Winner: ', player2.toString()]);
        player1.lose();
        player2.win();
    else
        disp('Even...');
        player1.even();
        player2.even();
    end
end
disp('Total result:');
disp(player1.toString());
disp(player2.toString());

実行結果

>> main 314 15
（中略）
Total result:
[Taro:10000 games, 3153 win, 3565 lose]
[Hana:10000 games, 3565 win, 3153 lose]