变量不递减for循环

Question

如果条件为真，我想减少索引。但是当我执行i = i-1时，它就开始循环。下面有一个例子。

for i = 1:sizex
for j = 2:unix
    if temp == uniorderxy(j,1)
       manDist = abs((uniorderxy(j,2)-xy(i,1)))+abs((uniorderxy(j,3)-xy(i,2)));
       if manDist <= temDist
           temDist = manDist;
           temX = uniorderxy(j,2);
           temY = uniorderxy(j,3);              
       end
       if j == unix
           temX = uniorderxy(j,2);
           temY = uniorderxy(j,3);
           temxy = [temX temY];
           xy = [xy; temxy];
       end
    else
        temp = uniorderxy(j,1);
        temxy = [temX temY];
        xy = [xy; temxy];
        i = i+1;
        j = j-1;
        [sizex, y] = size(xy);
        temDist = 100;
    end
end
end

在其他部分，应减小 j值。例如，当j=5时应将其递减为4，以便在for循环再次启动时应以5继续。但是在我的代码中，它将继续以6继续。