Not enough input arguments.

Hi y'all, I'm trying to create a function that can determine the rank, pivots, and free variables of a matrix without just using rank(A). I thought my code looked good but whenever I try to run it it tells me I need more input arguments. I'm pretty new to Matlab and cannot figure out what I is wrong with it. My code is here:

function csolve(A)
[num_rows, num_cols] = size(A);
free_vars = 1:1:num_cols;
pivots = [];
R = rref(A);
for i = 1:1:num_rows
    for j = 1:1:num_cols
        if R(i,j) == 1
            pivots = [pivots, j];
            break
        end
        rank = length(pivots);
        free_vars = free_vars(pivots);
    end
end
fprintf("The rank of the coefficient matrix is " + rank + ".");
fprintf("Pivot variables: " + pivots);
fprintf("Free variables: " + free_vars);

Like I said, I'm new so it's very possible that this code will not work correctly anyways, if you can find what input I need to add, that would be greatly appreciated!

[Walter Roberson]

How are you invoking this code?

Answer 1

[Sai Sri Pathuri]

I assume you called the function as below or hit the Run button, which results in the error 'Not enough input arguments'.

csolve

The function expects a matrix as an input. Since you are not passing any input, the error is being thrown. Define matrix A for which the rank, pivots, and free variables are to be determined and call the function in command window as

csolve(A)