Finding the relative error between arrays can be useful, for instance, in determining whether an iterative function is converging to the correct solution.
I use this function to test whether adjustments to my numerical solver is approaching the analytical solutions, but of course there are many applications where an indicative error would be useful.

To use the function is simple. With the arrays/matrices you want to compare at hand:

relError( A,B,C,... )

where size(A)=size(B)=size(C).

The function outputs a 2D array of size nArgs x nArgs comparing each input to each input. Use 'display' parameter to suppress the output text.

Example:

A=[1 2];
B=[1 2];
C=[2 4];
err = relError(A,B,C,'display',false)

err =
A B C
A --> 0 0 100
B --> 0 0 100
C --> 50 50 0

So for the error between the first argument and the third argument, use err(1,3).