edis_move.m

国际象棋程序,解压到当前目录,在matlab窗口输入chess即可应用

function EDIs_move
% EDIs_move   Executes EDIs move and updates the game history
% EDIs move is executed and the game history is updated.
%
% In this version EDI is pretty greedy. He looks whether there is
% something to "eat"(beat). If there is something to eat, he does without
% regard, whether he will loose something or even wether he gets himself
% into a check. Hence, illegal moves can occure.
% Actually I implemented already a "is_in_check" function (used for the 
% castling). In one of my next steps I will integrate it here.
% 
% How does EDI work? For each of his figures he looks out for the best
% move. The best move for each figues is determined in each corresponding
% figure classe (i.e. Knight). From all the best moves he chooses the one
% which promisses the highest gain. Right now he looks only half a move
% ahead.
%
%% Used Parameters
% * global board ... chess board and related information
% * global EDIs ... global information about EDI (i.e. color)
% * global history ... game history (all the past moves)
%
% Example
% Let's say, we are in the middle of a game. Then EDI computes the next
% half-move, performs it and also records it.
%
% See also: Chess, stopCursor, Knight, addHistoryMove 
%
%% Signature
% Author: W.Garn
% E-Mail: [e-mail]
% Date: 2006/03/23 12:00:00 
% 
% Copyright 2006 W.Garn
%
%% Last modifications
% * 30/3/2006 EDI sees that he "is in check", tries with a "best move" to
% avoid the loss.
%

global board
global EDIs
global history
global game

logFlag = 1; logFile=1;
% first evaluate the move

% select figure
if logFlag, fprintf(logFile,'EDI started ...\n'); end
if EDIs.color %white
    ef = board.white;
else
    ef = board.black;
end

%---------------------------------------------------------------
% get for each figure, its best move
fig  = {}; % figures
from = {}; % from where
to   = {}; % to where
gain = [];
fig_nb = 1; % number of figure
for i=1:8
    for j=1:8
        if ef(i,j)>0 % Edis figure
            fig{fig_nb} = board.figures(i,j);
            from{fig_nb} = [i j];
            [name, handle_chess_figure] = getFigureName(fig{fig_nb});
            if ~isempty(handle_chess_figure)
                [tf, ga] = handle_chess_figure('best_move',[i j]);
                if ~isempty(tf) % there is a best move
                    to{fig_nb}   = tf;
                    gain(fig_nb) = ga;
                    fig_nb       = fig_nb+1;
                end
            end
        end
    end
end
if logFlag, fprintf(logFile,'EDI has analysed all his figures.\n'); end

if ~isempty(gain)
    % choose figure which gives the best gain
    I = find ( gain == max(gain)); %figures with max. gain

    % select one of the figures with max. gain randomly
    sI = ceil(length(I)*rand); %(0,1]

    % is in check
    [answer, color] = is_in_check(from{I(sI)}, to{I(sI)});
    if logFlag, if answer, fprintf(logFile,'EDI identified check!\n');end, end

    %---------------------------------------------------------------
    % if check then systematic approach
    % 1. is there a best move which prohibits the check
    check=answer; %1...check, 0...no check
    k=0;
    if (answer && color(1)==EDIs.color) || length(color)==2 % equals EDI is in check then
        % systematic approach of choosing a figure
        [s,I] = sort(gain);

        k = length(s);
        while check && k>0
            sI = I(k);
            if ~is_in_check(from{sI}, to{sI})
                check=0; % found a way to avoid the check!
                if logFlag, fprintf(logFile,'A best move to avoid the check: %s to %s.\n',matrix2chess(from{sI}),matrix2chess(to{sI}));end
            end
            k=k-1;
        end
    end

    %--------------
    % 2. if no best move prohibits the check, then look for alternatives
    if k==0 && check && color(1)==EDIs.color % found no way to avoid check, using the best moves
        if logFlag, fprintf(logFile,'EDI can not avoid check!\n',name);end
        % there is no best move to avoid the check.

        % alternatevly implement ...
        % 1. run away
        EDIs_King_pos = King('getPosition',EDIs.color);
        P = King('possible_moves',EDIs_King_pos); % all possible moves
        if ~isempty(P)
            % perform move
            if logFlag, fprintf(logFile,'EDI will run away with his King.\n'); end
            King('move',EDIs_King_pos{1} , P(1,:)); % to the first possible field

            % update record
            addHistoryMove(EDIs_King_pos{1},P(1,:));
            if EDIs.color %white
                fprintf(1, [num2str(board.move_nb) '. ' history.white{length(history.white)} '\t\t'] );
            else
                fprintf(1, [history.black{length(history.black)} '\n'] );
            end
            if logFlag, fprintf(logFile,'EDI recored his %i. move.\n',board.move_nb); end
        else % no field to go to
            game.status = -1; % Edi surrenders
        end
        % 2. beat attacking figure
        % 3. put something in between

        %---------------------------------------------------------------
        % perform move and register it (if no check problem occured)
    elseif game.status>0 % game is still on

        % perform move
        [name, handle_chess_figure] = getFigureName(fig{I(sI)});
        if logFlag, fprintf(logFile,'EDI will move his %s.\n',name); end
        if ~isempty(handle_chess_figure)
            handle_chess_figure('move',from{I(sI)} , to{I(sI)});
        end
        if logFlag, fprintf(logFile,'EDI moved his %s.\n',name); end

        % update record
        addHistoryMove(from{I(sI)},to{I(sI)});
        if EDIs.color %white
            fprintf(1, [num2str(board.move_nb) '. ' history.white{length(history.white)} '\t\t'] );
        else
            fprintf(1, [history.black{length(history.black)} '\n'] );
        end
        if logFlag, fprintf(logFile,'EDI recored his %i. move.\n',board.move_nb); end
    end
else % no best move found
    game.status = -1; % Edi surrenders
end