Array indices must be positive integers or logical values.

I am so confused why would I get this error. One minute the code is running fine and produces plots, the next is no longer running. What is the problem with the function Rho? I cleared my workspace multiple times in case something was stuck there but still I am getting the same error. The code was working fine before.

Error message:

Array indices must be positive integers or logical values.

Error in Rho (line 35)
            rho(1) = rho(1)+ q*(x_p(i) - x(end-1))/(dx^2); % rhoj

Error in WeakBeam (line 157)
    [rho] = Rho(rhoe, xe, x, dx, qe);

I will be posting the code as well for you to run.

Answer 1

[Steven Lord]

If x only has one element, x(end-1) is an attempt to access element 0 of x. Arrays in MATLAB don't have an element 0. Their first element is element 1.

You may also receive this error if x is empty, has zero elements. In that case x(end-1) attempts to access element -1 of x. Arrays in MATLAB also don't have an element -1.

[Jamie Al]

x is an array of 0:1:101 elements so I don't see why would this be a problem cause here x(end-1) would be 99?