Can someone explain to me why I'm getting "Not enough input arguments" in line 2

function Fn = Fnorm(A)
[r,c] = size(A);
sum = 0;
for i=1:r
    for j=1:c
sum = sum + (A(i,j) * A(i,j));
    end
end
Fn = sqrt(sum);
end

Answer 1

[John D'Errico]

For the simple reason that you named a function named size. Don't do this. Type this at the command line:

which size -all

If it shows a function that you created, change the name. And in the future, don't name things with names that already exist as useful tools in MATLAB.

Answer 2

[Walter Roberson]

You tried to run your function, Fnorm, without passing any values into it. For example you might have tried to run it by pressing the green Run button. You need to go to the command line and pass it an array, such as

A = rand(5,7);
result = Fnorm(A)