N x N identity matrix in MATLAB

Question

I am having difficulty creating a generic N x N identity matrix in Matlab.

I am given a system where

Ai,j =

{1, if i does not equal j

{n, if i = j}

You are asked to compute this when the value of the identity matrix n = 10, n = 20.

What I don't see is how to apply matrix indexing here. That is easy enough to do, but how do I account for the given linear system?

user_4418874 · Answer

There is a builtin function for creating a unit matrix called eye.

Also, ones(n,m) creates a matrix of ones.

For a square matrix use (n-1)*eye(n) + ones(n) and for non-square (n-1)*eye(n, m) + ones(n, m)