tsp_possubtract.m

用粒子群方法解决TSP（旅行商）问题

function result = TSP_posSubtract(a,b)
n = size(a,2);
len = 0;
pa = zeros(1,n);
pb = zeros(1,n);
for i=1:n
    pa(a(i)) = i;
    pb(b(i)) = i;
    if (a(i) ~= b(i))
        len = len + 1;
    end % if...
end % for...

% the two sequence are identical...
if (len == 0)
    result = 0;
    return;
end % if...
j = 1;
result = zeros(1,2);
for i=1:len-1
    while(a(j) == b(j) && j < n)
        j = j + 1;
    end % while...
    if (j == n)
        return;
    end % if...
    % result(i,:) = [j pa(b(j))];
    if (i ~= 1)
        result = [result;j pa(b(j))];
    else
        result = [j pa(b(j))];
    end % if...
    % one bit permutation...
    t = a(j);
    a(j) = a(pa(b(j)));
    a(pa(b(j))) = t;
    % update the position record vector...
    pa(t) = pa(b(j));
    pa(b(j)) = j;
end % for...