Array indices must be positive integers or logical values.

Why do I keep getting this error? Doesn't RRED should take care of indices?

Answer 1

[Walter Roberson]

You have a symbolic variable named rref so rref(X) is a request to index the rref variable.

[Hyeonjin]

I really appreciate your anwer.

But I did not make any symbolic variable named rref. If it is generated, how do I remove it?

[Hyeonjin]

I solved it!

So the file is effected by other files in the folder. So I needed to get rid of rref variable there and clear workspace in home tap.