How to adjust dimension in xx

function f =  watch2(b,x,M,n,lb,ub,costfun)
xx=zeros(M,n);
for i=1:M
    for j=1:n
        xx(i,:)= (x(i,j) - b)+ ((x(i,j) + b)-(x(i,j)-b)).*rand; 
    end
end
xx;
if ob(xx)<ob(x)  
    x(i,:)=xx(i,:);
end %fw=xx
f=lb+(ub-lb).*x; 
end

Answer 1

[KSSV]

for i=1:M
    for j=1:n
        xx(i,j)= (x(i,j) - b)+ ((x(i,j) + b)-(x(i,j)-b)).*rand; 
    end
end