sum up Loop of random numbers

The size of X1, X2, Y1,Y2 are 200x200 with different values.

I have the following code (the code is shortened and simplified so please don't ask why I do it this way):

for r = 1:100

% get random numbers for array X1

a_x = (5*rand(size(X1))-2.5);

a_y = (8*rand(size(Y1))-2.5);

l_x = (5*rand(size(X1))-2.5);

l_y = (8*rand(size(Y1))-2.5);

% get random numbers for array X2

a_x2 = (5*rand(size(X1))-2.5);

a_y2 = (8*rand(size(Y1))-2.5);

l_x2 = (5*rand(size(X1))-2.5);

l_y2 = (8*rand(size(Y1))-2.5);

% Add random numbers to the values in X1 and X2

X1_MC = X1+(a_x+l_x);

Y1_MC = Y1+(a_y+l_y);

X2_MC = X2+(a_x2+l_x2);

Y2_MC = Y2+(a_y2+l_y2);

% Subtract cell X1_MC(100,175) from cell X2_MC(100,25)

Q(r) = X1_MC(100,175)

X(r) = X2_MC(100,25)

QX(r) = Q(r) - X(r)

end

I can not get the values in a (a_x a_y a_x2 a_y2) and l (l_x l_y l_x2 l_y2) to recalculate for each iteration. They stay the same at the end, so i get alway the same values in QX.

[Ankit]

I didn't see any a and b. Could you please add those to your problem

X1 = zeros(200,200); 
X2 = zeros(200,200); 
Y1 = zeros(200,200); 
Y2 = zeros(200,200); 
Q = zeros(100,1); 
X = zeros(100,1); 
QX = zeros(100,1); 
for r = 1:100
    % get random numbers for array X1
    a_x = (5*rand(size(X1))-2.5);
    a_y = (8*rand(size(Y1))-2.5);
    l_x = (5*rand(size(X1))-2.5);
    l_y = (8*rand(size(Y1))-2.5);
    % get random numbers for array X2
    a_x2 = (5*rand(size(X1))-2.5);
    a_y2 = (8*rand(size(Y1))-2.5);
    l_x2 = (5*rand(size(X1))-2.5);
    l_y2 = (8*rand(size(Y1))-2.5);
    % Add random numbers to the values in X1 and X2
    X1_MC = X1+(a_x+l_x);
    Y1_MC = Y1+(a_y+l_y);
    X2_MC = X2+(a_x2+l_x2);
    Y2_MC = Y2+(a_y2+l_y2);
    % Subtract cell X1_MC(100,175) from cell X2_MC(100,25)
    Q(r) = X1_MC(100,175);
    X(r) = X2_MC(100,25);
    QX(r) = Q(r) - X(r);
end
plot(QX);xlabel('r');ylabel('QX');hold on

[Lucas Kellermann]

Sorry I mean all a and l

[Benjamin Thompson]

Can you post a full script demonstrating the problem, that includes your definition of X1 and Y1?