Debugging matrix dimensions error

I've a piece of code as follows:

data.r = zeros(Nr,N_experiments,end_sample-start_sample+1);
data.u = zeros(Nu,N_experiments,end_sample-start_sample+1);
data.y = zeros(Ny,N_experiments,end_sample-start_sample+1);

for k_exp = 1:N_experiments
    for k_real = 1:N_realizations
        for nr = 1:Nr
            data.r(nr, k_exp,1:(end_sample-start_sample+1),k_real) = R((((k_exp-1)*N_realizations+(k_real-1))*(end_sample-start_sample+1)+1):(((k_exp-1)*N_realizations+k_real)*(end_sample-start_sample+1)),nr)';
        end
        for nu = 1:Nu
            data.u(nu, k_exp,1:(end_sample-start_sample+1),k_real) = U((((k_exp-1)*N_realizations+(k_real-1))*(end_sample-start_sample+1)+1):(((k_exp-1)*N_realizations+k_real)*(end_sample-start_sample+1)),nu)';
        end
        for ny = 1:Nu
            data.y(ny, k_exp,1:(end_sample-start_sample+1),k_real) = Y((((k_exp-1)*N_realizations+(k_real-1))*(end_sample-start_sample+1)+1):(((k_exp-1)*N_realizations+k_real)*(end_sample-start_sample+1)),ny)';
        end
    end
end

Dimensions as follows: Nr=2,Nu=2,Ny=2,N_experiments=2,N_realizations=1,start_sample=1441,end_sample=159951, R,U,Y=158511x2.

I get a 'Index exceeds matrix dimensions' error. This doesn't happen for k_exp = 1. I'm a little confused as some friends have used this same snippet and it has worked for them. What am I missing out?

Answer 1

[James Tursa]

How to debug:

Type the following at the MATLAB prompt:

dbstop if error

Then run your code. When the error occurs, the code will pause with all variables intact. Examine the variables on the line in question to see what the actual dimensions are. Then backtrack in your code to figure out why the dimensions or indexing are not what you expected.