Error using sparse. Index exceeds matrix dimensions.

I am trying to run this piece of code to do more operations on the graph G. However, I get the error cited in the title.

A = load('file.txt', '-ascii');
i = A(:,1);
j = A(:,2);

num = 11355;  
G = sparse(i,j,1,num,num);

I am not sure if this is because sparse cannot make matrices that are in the order of magnitude of the prescribed matrix or this is a memory issue. I am relatively new to Matlab, so I am not sure what to do with it.

Thanks in advance.

Answer 1

[Star Strider]

I doubt if it’s a memory issue, since

G = sparse(num,num);
whos G

yields

    Name          Size               Bytes  Class     Attributes

    G         11355x11355            90864  double    sparse

I would check to see if any elements of ‘i’ or ‘j’ are greater than ‘num’.

[Lujaina Abuerban]

I traversed both 'i' and 'j' looking for their greatest elements, they yield 11354 and 11355 respectively. So, no, there are no elements greater than 'num'.

[Star Strider]

Oh, well.

You don’t have to scan them. Just use the max function.

A zero or a non-integer would throw a different error, so those aren’t the problem.