max(dg) returns "Subscript indices must either be real positive integers or logicals."

Any reasons why? dg is an n x 1 column vector.

Answer 1

[John D'Errico]

Simple. Don't create a variable named max. How should MATLAB know if you do that, that then when you try to use the FUNCTION named max, what you really want to do? MATLAB assumes that you know what you are doing.

So when you created a variable max, then used the form max(dg), MATLAB assumes that you knew what you were doing, that you did this for a good reason. It then tries to index the variable max, using dg as an index.