Index exceeds the number of array elements (0) error. Help please

Hi,

Below is my very simple code. What is wrong with this. Could you help me please?

function [E]=mainy()
clc
clear all
syms x t eta zeta xsi m tau epsilon k


for j=1:3
    WK=[];
  w(j)=j*2*x  
end

for k=1:3
UXT=[];
UXT(k)=k*x
    
end
for i=1:3
    E=[];
E=UXT(i)-WK(i)
%  E=(UXT(k)-WK(k))/(UXT(k))
end
end

[KALYAN ACHARJYA]

Here

[OZGUR YILDIRIM]

I dont have time for long course. Why dou you answer like this Kalyan? What is wrong with you? If you think my question is simple then just skip.

Answer 1

[Walter Roberson]

It is not advisable to use clc inside most functions. There is not typically a reason to clear the command window.

You should never "clear all" inside a function. If you use "clear all" at all, it should only be inside one script that you use to reset the state of MATLAB when you switch tasks. "clear all" inside a function is like Wyle E. Coyote blowing up the bridge he is standing on.

Setting a variable to [] in every iteration of a loop is not productive in most cases. If the variable is not being set to something else inside the loop before being set to [] then you are just wasting time.

Every iteration of for j you clear all of WK, making it into an array of size 0. Then in for i you try to access WK(1) on the first iteration, but offset (1) is not there because you wrote [] to WK (multiple times)

[OZGUR YILDIRIM]

Thank you very much for your time. Your comments are very helpfull.