Determining criteria from two different arrays

d = an array of 3 columns, u_sign an array of (:,:,1,:) (from a nc file so it seems to retain a 4D structure)

I am trying to find it where for the values of d(:,1) it searches whether the u_sign value at d(:,2) + 2 is greater than the u_sign value at d(:,2). I can't seem to get it to work. It says the index exceeds matrix dimensions but I can't work out why. Thanks for any answers :)

B = zeros(length(data),2);
C = zeros(length(data),2);

 for k = 1:length(d);  
        u_sign = u_sign(:,:,1,d(k,1));
          %(getting the array into the right shape):
        u_sign = rot90(u_sign);
        u_sign = [(u_sign(:,(73:144))) (u_sign(:,(1:72)))];
        u_sign = u_sign((44:67),:);

      %the test: u_sign(r,c) > u_sign(r+2,c)  (below):
    if u_sign(d(k,2),d(k,3)) > u_sign((d(k,2))+2,d(k,3)),...
            B(k,:) = [d(k,2),d(k,3)];
    else C = 0;
    end       
  end 

[ii jj] = find(B > 0);
new_data = [ii jj]
clear B C

[Geoff Hayes]

Oliver - at which line is the error being generated? Please also include the dimensions of your data, d, and u_sign matrices. As well, are the value of d valid so that they can be used as indices within u_sign?

[Star Strider]

What is the maximum value of ‘d(:,2)’ and ‘d(:,3)’?

What is the row size of ‘u_sign’?